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Author SHA1 Message Date
Linus Torvalds
2d28e01dca Merge branch 'akpm' (patches from Andrew) 
Merge misc fixes from Andrew Morton:
 "2 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  hugetlbfs: fix races and page leaks during migration
  kasan: turn off asan-stack for clang-8 and earlier
 2019-03-01 09:04:59 -08:00
Mike Kravetz
cb6acd01e2 hugetlbfs: fix races and page leaks during migration 
hugetlb pages should only be migrated if they are 'active'.  The
routines set/clear_page_huge_active() modify the active state of hugetlb
pages.

When a new hugetlb page is allocated at fault time, set_page_huge_active
is called before the page is locked.  Therefore, another thread could
race and migrate the page while it is being added to page table by the
fault code.  This race is somewhat hard to trigger, but can be seen by
strategically adding udelay to simulate worst case scheduling behavior.
Depending on 'how' the code races, various BUG()s could be triggered.

To address this issue, simply delay the set_page_huge_active call until
after the page is successfully added to the page table.

Hugetlb pages can also be leaked at migration time if the pages are
associated with a file in an explicitly mounted hugetlbfs filesystem.
For example, consider a two node system with 4GB worth of huge pages
available.  A program mmaps a 2G file in a hugetlbfs filesystem.  It
then migrates the pages associated with the file from one node to
another.  When the program exits, huge page counts are as follows:

  node0
  1024    free_hugepages
  1024    nr_hugepages

  node1
  0       free_hugepages
  1024    nr_hugepages

  Filesystem                         Size  Used Avail Use% Mounted on
  nodev                              4.0G  2.0G  2.0G  50% /var/opt/hugepool

That is as expected.  2G of huge pages are taken from the free_hugepages
counts, and 2G is the size of the file in the explicitly mounted
filesystem.  If the file is then removed, the counts become:

  node0
  1024    free_hugepages
  1024    nr_hugepages

  node1
  1024    free_hugepages
  1024    nr_hugepages

  Filesystem                         Size  Used Avail Use% Mounted on
  nodev                              4.0G  2.0G  2.0G  50% /var/opt/hugepool

Note that the filesystem still shows 2G of pages used, while there
actually are no huge pages in use.  The only way to 'fix' the filesystem
accounting is to unmount the filesystem

If a hugetlb page is associated with an explicitly mounted filesystem,
this information in contained in the page_private field.  At migration
time, this information is not preserved.  To fix, simply transfer
page_private from old to new page at migration time if necessary.

There is a related race with removing a huge page from a file and
migration.  When a huge page is removed from the pagecache, the
page_mapping() field is cleared, yet page_private remains set until the
page is actually freed by free_huge_page().  A page could be migrated
while in this state.  However, since page_mapping() is not set the
hugetlbfs specific routine to transfer page_private is not called and we
leak the page count in the filesystem.

To fix that, check for this condition before migrating a huge page.  If
the condition is detected, return EBUSY for the page.

Link: http://lkml.kernel.org/r/74510272-7319-7372-9ea6-ec914734c179@oracle.com
Link: http://lkml.kernel.org/r/20190212221400.3512-1-mike.kravetz@oracle.com
Fixes: bcc5422230 ("mm: hugetlb: introduce page_huge_active")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: <stable@vger.kernel.org>
[mike.kravetz@oracle.com: v2]
  Link: http://lkml.kernel.org/r/7534d322-d782-8ac6-1c8d-a8dc380eb3ab@oracle.com
[mike.kravetz@oracle.com: update comment and changelog]
  Link: http://lkml.kernel.org/r/420bcfd6-158b-38e4-98da-26d0cd85bd01@oracle.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-03-01 09:02:33 -08:00
Jann Horn
0a1d52994d mm: enforce min addr even if capable() in expand_downwards() 
security_mmap_addr() does a capability check with current_cred(), but
we can reach this code from contexts like a VFS write handler where
current_cred() must not be used.

This can be abused on systems without SMAP to make NULL pointer
dereferences exploitable again.

Fixes: 8869477a49 ("security: protect from stack expansion into low vm addresses")
Cc: stable@kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-27 17:27:02 -08:00
Darrick J. Wong
29b00e6099 tmpfs: fix uninitialized return value in shmem_link 
When we made the shmem_reserve_inode call in shmem_link conditional, we
forgot to update the declaration for ret so that it always has a known
value.  Dan Carpenter pointed out this deficiency in the original patch.

Fixes: 1062af920c ("tmpfs: fix link accounting when a tmpfile is linked in")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Matej Kupljen <matej.kupljen@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-25 11:49:22 -08:00
Linus Torvalds
53a41cb7ed Revert "x86/fault: BUG() when uaccess helpers fault on kernel addresses" 
This reverts commit 9da3f2b740.

It was well-intentioned, but wrong.  Overriding the exception tables for
instructions for random reasons is just wrong, and that is what the new
code did.

It caused problems for tracing, and it caused problems for strncpy_from_user(),
because the new checks made perfectly valid use cases break, rather than
catch things that did bad things.

Unchecked user space accesses are a problem, but that's not a reason to
add invalid checks that then people have to work around with silly flags
(in this case, that 'kernel_uaccess_faults_ok' flag, which is just an
odd way to say "this commit was wrong" and was sprinked into random
places to hide the wrongness).

The real fix to unchecked user space accesses is to get rid of the
special "let's not check __get_user() and __put_user() at all" logic.
Make __{get|put}_user() be just aliases to the regular {get|put}_user()
functions, and make it impossible to access user space without having
the proper checks in places.

The raison d'être of the special double-underscore versions used to be
that the range check was expensive, and if you did multiple user
accesses, you'd do the range check up front (like the signal frame
handling code, for example).  But SMAP (on x86) and PAN (on ARM) have
made that optimization pointless, because the _real_ expense is the "set
CPU flag to allow user space access".

Do let's not break the valid cases to catch invalid cases that shouldn't
even exist.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tobin C. Harding <tobin@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-25 09:10:51 -08:00
Michal Hocko
891cb2a72d mm, memory_hotplug: fix off-by-one in is_pageblock_removable 
Rong Chen has reported the following boot crash:

    PGD 0 P4D 0
    Oops: 0000 [#1] PREEMPT SMP PTI
    CPU: 1 PID: 239 Comm: udevd Not tainted 5.0.0-rc4-00149-gefad4e4 #1
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
    RIP: 0010:page_mapping+0x12/0x80
    Code: 5d c3 48 89 df e8 0e ad 02 00 85 c0 75 da 89 e8 5b 5d c3 0f 1f 44 00 00 53 48 89 fb 48 8b 43 08 48 8d 50 ff a8 01 48 0f 45 da <48> 8b 53 08 48 8d 42 ff 83 e2 01 48 0f 44 c3 48 83 38 ff 74 2f 48
    RSP: 0018:ffff88801fa87cd8 EFLAGS: 00010202
    RAX: ffffffffffffffff RBX: fffffffffffffffe RCX: 000000000000000a
    RDX: fffffffffffffffe RSI: ffffffff820b9a20 RDI: ffff88801e5c0000
    RBP: 6db6db6db6db6db7 R08: ffff88801e8bb000 R09: 0000000001b64d13
    R10: ffff88801fa87cf8 R11: 0000000000000001 R12: ffff88801e640000
    R13: ffffffff820b9a20 R14: ffff88801f145258 R15: 0000000000000001
    FS:  00007fb2079817c0(0000) GS:ffff88801dd00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000006 CR3: 000000001fa82000 CR4: 00000000000006a0
    Call Trace:
     __dump_page+0x14/0x2c0
     is_mem_section_removable+0x24c/0x2c0
     removable_show+0x87/0xa0
     dev_attr_show+0x25/0x60
     sysfs_kf_seq_show+0xba/0x110
     seq_read+0x196/0x3f0
     __vfs_read+0x34/0x180
     vfs_read+0xa0/0x150
     ksys_read+0x44/0xb0
     do_syscall_64+0x5e/0x4a0
     entry_SYSCALL_64_after_hwframe+0x49/0xbe

and bisected it down to commit efad4e475c ("mm, memory_hotplug:
is_mem_section_removable do not pass the end of a zone").

The reason for the crash is that the mapping is garbage for poisoned
(uninitialized) page.  This shouldn't happen as all pages in the zone's
boundary should be initialized.

Later debugging revealed that the actual problem is an off-by-one when
evaluating the end_page.  'start_pfn + nr_pages' resp 'zone_end_pfn'
refers to a pfn after the range and as such it might belong to a
differen memory section.

This along with CONFIG_SPARSEMEM then makes the loop condition
completely bogus because a pointer arithmetic doesn't work for pages
from two different sections in that memory model.

Fix the issue by reworking is_pageblock_removable to be pfn based and
only use struct page where necessary.  This makes the code slightly
easier to follow and we will remove the problematic pointer arithmetic
completely.

Link: http://lkml.kernel.org/r/20190218181544.14616-1-mhocko@kernel.org
Fixes: efad4e475c ("mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: <rong.a.chen@intel.com>
Tested-by: <rong.a.chen@intel.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:01 -08:00
Daniel Vetter
6c8fcc096b mm: don't let userspace spam allocations warnings 
memdump_user usually gets fed unchecked userspace input.  Blasting a
full backtrace into dmesg every time is a bit excessive - I'm not sure
on the kernel rule in general, but at least in drm we're trying not to
let unpriviledge userspace spam the logs freely.  Definitely not entire
warning backtraces.

It also means more filtering for our CI, because our testsuite exercises
these corner cases and so hits these a lot.

Link: http://lkml.kernel.org/r/20190220204058.11676-1-daniel.vetter@ffwll.ch
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:01 -08:00
Qian Cai
6373dca16c slub: fix a crash with SLUB_DEBUG + KASAN_SW_TAGS 
In process_slab(), "p = get_freepointer()" could return a tagged
pointer, but "addr = page_address()" always return a native pointer.  As
the result, slab_index() is messed up here,

    return (p - addr) / s->size;

All other callers of slab_index() have the same situation where "addr"
is from page_address(), so just need to untag "p".

    # cat /sys/kernel/slab/hugetlbfs_inode_cache/alloc_calls

    Unable to handle kernel paging request at virtual address 2bff808aa4856d48
    Mem abort info:
      ESR = 0x96000007
      Exception class = DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
    Data abort info:
      ISV = 0, ISS = 0x00000007
      CM = 0, WnR = 0
    swapper pgtable: 64k pages, 48-bit VAs, pgdp = 0000000002498338
    [2bff808aa4856d48] pgd=00000097fcfd0003, pud=00000097fcfd0003, pmd=00000097fca30003, pte=00e8008b24850712
    Internal error: Oops: 96000007 [#1] SMP
    CPU: 3 PID: 79210 Comm: read_all Tainted: G             L    5.0.0-rc7+ #84
    Hardware name: HPE Apollo 70             /C01_APACHE_MB         , BIOS L50_5.13_1.0.6 07/10/2018
    pstate: 00400089 (nzcv daIf +PAN -UAO)
    pc : get_map+0x78/0xec
    lr : get_map+0xa0/0xec
    sp : aeff808989e3f8e0
    x29: aeff808989e3f940 x28: ffff800826200000
    x27: ffff100012d47000 x26: 9700000000002500
    x25: 0000000000000001 x24: 52ff8008200131f8
    x23: 52ff8008200130a0 x22: 52ff800820013098
    x21: ffff800826200000 x20: ffff100013172ba0
    x19: 2bff808a8971bc00 x18: ffff1000148f5538
    x17: 000000000000001b x16: 00000000000000ff
    x15: ffff1000148f5000 x14: 00000000000000d2
    x13: 0000000000000001 x12: 0000000000000000
    x11: 0000000020000002 x10: 2bff808aa4856d48
    x9 : 0000020000000000 x8 : 68ff80082620ebb0
    x7 : 0000000000000000 x6 : ffff1000105da1dc
    x5 : 0000000000000000 x4 : 0000000000000000
    x3 : 0000000000000010 x2 : 2bff808a8971bc00
    x1 : ffff7fe002098800 x0 : ffff80082620ceb0
    Process read_all (pid: 79210, stack limit = 0x00000000f65b9361)
    Call trace:
     get_map+0x78/0xec
     process_slab+0x7c/0x47c
     list_locations+0xb0/0x3c8
     alloc_calls_show+0x34/0x40
     slab_attr_show+0x34/0x48
     sysfs_kf_seq_show+0x2e4/0x570
     kernfs_seq_show+0x12c/0x1a0
     seq_read+0x48c/0xf84
     kernfs_fop_read+0xd4/0x448
     __vfs_read+0x94/0x5d4
     vfs_read+0xcc/0x194
     ksys_read+0x6c/0xe8
     __arm64_sys_read+0x68/0xb0
     el0_svc_handler+0x230/0x3bc
     el0_svc+0x8/0xc
    Code: d3467d2a 9ac92329 8b0a0e6a f9800151 (c85f7d4b)
    ---[ end trace a383a9a44ff13176 ]---
    Kernel panic - not syncing: Fatal exception
    SMP: stopping secondary CPUs
    SMP: failed to stop secondary CPUs 1-7,32,40,127
    Kernel Offset: disabled
    CPU features: 0x002,20000c18
    Memory Limit: none
    ---[ end Kernel panic - not syncing: Fatal exception ]---

Link: http://lkml.kernel.org/r/20190220020251.82039-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
557ea25383 kasan, slab: remove redundant kasan_slab_alloc hooks 
kasan_slab_alloc() calls in kmem_cache_alloc() and kmem_cache_alloc_node()
are redundant as they are already called via slab_alloc/slab_alloc_node()->
slab_post_alloc_hook()->kasan_slab_alloc().  Remove them.

Link: http://lkml.kernel.org/r/4ca1655cdcfc4379c49c50f7bf80f81c4ad01485.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
51dedad06b kasan, slab: make freelist stored without tags 
Similarly to "kasan, slub: move kasan_poison_slab hook before
page_address", move kasan_poison_slab() before alloc_slabmgmt(), which
calls page_address(), to make page_address() return value to be
non-tagged.  This, combined with calling kasan_reset_tag() for off-slab
slab management object, leads to freelist being stored non-tagged.

Link: http://lkml.kernel.org/r/dfb53b44a4d00de3879a05a9f04c1f55e584f7a1.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
219667c23c kasan, slab: fix conflicts with CONFIG_HARDENED_USERCOPY 
Similarly to commit 96fedce27e ("kasan: make tag based mode work with
CONFIG_HARDENED_USERCOPY"), we need to reset pointer tags in
__check_heap_object() in mm/slab.c before doing any pointer math.

Link: http://lkml.kernel.org/r/9a5c0f958db10e69df5ff9f2b997866b56b7effc.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
dc15a8a254 kasan: prevent tracing of tags.c 
Similarly to commit 0d0c8de878 ("kasan: mark file common so ftrace
doesn't trace it") add the -pg flag to mm/kasan/tags.c to prevent
conflicts with tracing.

Link: http://lkml.kernel.org/r/9c4c3ce5ccfb894c7fe66d91de7c1da2787b4da4.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Qian Cai <cai@lca.pw>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
3f41b60938 kasan: fix random seed generation for tag-based mode 
There are two issues with assigning random percpu seeds right now:

1. We use for_each_possible_cpu() to iterate over cpus, but cpumask is
   not set up yet at the moment of kasan_init(), and thus we only set
   the seed for cpu #0.

2. A call to get_random_u32() always returns the same number and produces
   a message in dmesg, since the random subsystem is not yet initialized.

Fix 1 by calling kasan_init_tags() after cpumask is set up.

Fix 2 by using get_cycles() instead of get_random_u32(). This gives us
lower quality random numbers, but it's good enough, as KASAN is meant to
be used as a debugging tool and not a mitigation.

Link: http://lkml.kernel.org/r/1f815cc914b61f3516ed4cc9bfd9eeca9bd5d9de.1550677973.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Darrick J. Wong
1062af920c tmpfs: fix link accounting when a tmpfile is linked in 
tmpfs has a peculiarity of accounting hard links as if they were
separate inodes: so that when the number of inodes is limited, as it is
by default, a user cannot soak up an unlimited amount of unreclaimable
dcache memory just by repeatedly linking a file.

But when v3.11 added O_TMPFILE, and the ability to use linkat() on the
fd, we missed accommodating this new case in tmpfs: "df -i" shows that
an extra "inode" remains accounted after the file is unlinked and the fd
closed and the actual inode evicted.  If a user repeatedly links
tmpfiles into a tmpfs, the limit will be hit (ENOSPC) even after they
are deleted.

Just skip the extra reservation from shmem_link() in this case: there's
a sense in which this first link of a tmpfile is then cheaper than a
hard link of another file, but the accounting works out, and there's
still good limiting, so no need to do anything more complicated.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1902182134370.7035@eggly.anvils
Fixes: f4e0c30c19 ("allow the temp files created by open() to be linked to")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Matej Kupljen <matej.kupljen@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Michal Hocko
6ea183d60c mm: handle lru_add_drain_all for UP properly 
Since for_each_cpu(cpu, mask) added by commit 2d3854a37e
("cpumask: introduce new API, without changing anything") did not
evaluate the mask argument if NR_CPUS == 1 due to CONFIG_SMP=n,
lru_add_drain_all() is hitting WARN_ON() at __flush_work() added by
commit 4d43d395fe ("workqueue: Try to catch flush_work() without
INIT_WORK().") by unconditionally calling flush_work() [1].

Workaround this issue by using CONFIG_SMP=n specific lru_add_drain_all
implementation.  There is no real need to defer the implementation to
the workqueue as the draining is going to happen on the local cpu.  So
alias lru_add_drain_all to lru_add_drain which does all the necessary
work.

[akpm@linux-foundation.org: fix various build warnings]
[1] https://lkml.kernel.org/r/18a30387-6aa5-6123-e67c-57579ecc3f38@roeck-us.net
Link: http://lkml.kernel.org/r/20190213124334.GH4525@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Debugged-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Mel Gorman
94b3334cbe mm, page_alloc: fix a division by zero error when boosting watermarks v2 
Yury Norov reported that an arm64 KVM instance could not boot since
after v5.0-rc1 and could addressed by reverting the patches

  1c30844d2d ("mm: reclaim small amounts of memory when an external
  73444bc4d8 ("mm, page_alloc: do not wake kswapd with zone lock held")

The problem is that a division by zero error is possible if boosting
occurs very early in boot if the system has very little memory.  This
patch avoids the division by zero error.

Link: http://lkml.kernel.org/r/20190213143012.GT9565@techsingularity.net
Fixes: 1c30844d2d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Robin Murphy
311ade0eab mm/debug.c: fix __dump_page() for poisoned pages 
Evaluating page_mapping() on a poisoned page ends up dereferencing junk
and making PF_POISONED_CHECK() considerably crashier than intended:

    Unable to handle kernel NULL pointer dereference at virtual address 0000000000000006
    Mem abort info:
      ESR = 0x96000005
      Exception class = DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
    Data abort info:
      ISV = 0, ISS = 0x00000005
      CM = 0, WnR = 0
    user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000c2f6ac38
    [0000000000000006] pgd=0000000000000000, pud=0000000000000000
    Internal error: Oops: 96000005 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 2 PID: 491 Comm: bash Not tainted 5.0.0-rc1+ #1
    Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Dec 17 2018
    pstate: 00000005 (nzcv daif -PAN -UAO)
    pc : page_mapping+0x18/0x118
    lr : __dump_page+0x1c/0x398
    Process bash (pid: 491, stack limit = 0x000000004ebd4ecd)
    Call trace:
     page_mapping+0x18/0x118
     __dump_page+0x1c/0x398
     dump_page+0xc/0x18
     remove_store+0xbc/0x120
     dev_attr_store+0x18/0x28
     sysfs_kf_write+0x40/0x50
     kernfs_fop_write+0x130/0x1d8
     __vfs_write+0x30/0x180
     vfs_write+0xb4/0x1a0
     ksys_write+0x60/0xd0
     __arm64_sys_write+0x18/0x20
     el0_svc_common+0x94/0xf8
     el0_svc_handler+0x68/0x70
     el0_svc+0x8/0xc
    Code: f9400401 d1000422 f240003f 9a801040 (f9400402)
    ---[ end trace cdb5eb5bf435cecb ]---

Fix that by not inspecting the mapping until we've determined that it's
likely to be valid.  Now the above condition still ends up stopping the
kernel, but in the correct manner:

    page:ffffffbf20000000 is uninitialized and poisoned
    raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
    raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
    page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
    ------------[ cut here ]------------
    kernel BUG at ./include/linux/mm.h:1006!
    Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 1 PID: 483 Comm: bash Not tainted 5.0.0-rc1+ #3
    Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Dec 17 2018
    pstate: 40000005 (nZcv daif -PAN -UAO)
    pc : remove_store+0xbc/0x120
    lr : remove_store+0xbc/0x120
    ...

Link: http://lkml.kernel.org/r/03b53ee9d7e76cda4b9b5e1e31eea080db033396.1550071778.git.robin.murphy@arm.com
Fixes: 1c6fb1d89e ("mm: print more information about mapping in __dump_page")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Qian Cai
338cfaad49 slub: fix SLAB_CONSISTENCY_CHECKS + KASAN_SW_TAGS 
Enabling SLUB_DEBUG's SLAB_CONSISTENCY_CHECKS with KASAN_SW_TAGS
triggers endless false positives during boot below due to
check_valid_pointer() checks tagged pointers which have no addresses
that is valid within slab pages:

  BUG radix_tree_node (Tainted: G    B            ): Freelist Pointer check fails
  -----------------------------------------------------------------------------

  INFO: Slab objects=69 used=69 fp=0x          (null) flags=0x7ffffffc000200
  INFO: Object @offset=15060037153926966016 fp=0x

  Redzone: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 18 6b 06 00 08 80 ff d0  .........k......
  Object : 18 6b 06 00 08 80 ff d0 00 00 00 00 00 00 00 00  .k..............
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  Redzone: bb bb bb bb bb bb bb bb                          ........
  Padding: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  ZZZZZZZZZZZZZZZZ
  CPU: 0 PID: 0 Comm: swapper/0 Tainted: G    B             5.0.0-rc5+ #18
  Call trace:
    dump_backtrace+0x0/0x450
    show_stack+0x20/0x2c
    __dump_stack+0x20/0x28
    dump_stack+0xa0/0xfc
    print_trailer+0x1bc/0x1d0
    object_err+0x40/0x50
    alloc_debug_processing+0xf0/0x19c
    ___slab_alloc+0x554/0x704
    kmem_cache_alloc+0x2f8/0x440
    radix_tree_node_alloc+0x90/0x2fc
    idr_get_free+0x1e8/0x6d0
    idr_alloc_u32+0x11c/0x2a4
    idr_alloc+0x74/0xe0
    worker_pool_assign_id+0x5c/0xbc
    workqueue_init_early+0x49c/0xd50
    start_kernel+0x52c/0xac4
  FIX radix_tree_node: Marking all objects used

Link: http://lkml.kernel.org/r/20190209044128.3290-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
d36a63a943 kasan, slub: fix more conflicts with CONFIG_SLAB_FREELIST_HARDENED 
When CONFIG_KASAN_SW_TAGS is enabled, ptr_addr might be tagged.  Normally,
this doesn't cause any issues, as both set_freepointer() and
get_freepointer() are called with a pointer with the same tag.  However,
there are some issues with CONFIG_SLUB_DEBUG code.  For example, when
__free_slub() iterates over objects in a cache, it passes untagged
pointers to check_object().  check_object() in turns calls
get_freepointer() with an untagged pointer, which causes the freepointer
to be restored incorrectly.

Add kasan_reset_tag to freelist_ptr(). Also add a detailed comment.

Link: http://lkml.kernel.org/r/bf858f26ef32eb7bd24c665755b3aee4bc58d0e4.1550103861.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Qian Cai <cai@lca.pw>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
18e5066102 kasan, slub: fix conflicts with CONFIG_SLAB_FREELIST_HARDENED 
CONFIG_SLAB_FREELIST_HARDENED hashes freelist pointer with the address of
the object where the pointer gets stored.  With tag based KASAN we don't
account for that when building freelist, as we call set_freepointer() with
the first argument untagged.  This patch changes the code to properly
propagate tags throughout the loop.

Link: http://lkml.kernel.org/r/3df171559c52201376f246bf7ce3184fe21c1dc7.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Qian Cai <cai@lca.pw>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
a710122428 kasan, slub: move kasan_poison_slab hook before page_address 
With tag based KASAN page_address() looks at the page flags to see whether
the resulting pointer needs to have a tag set.  Since we don't want to set
a tag when page_address() is called on SLAB pages, we call
page_kasan_tag_reset() in kasan_poison_slab().  However in allocate_slab()
page_address() is called before kasan_poison_slab().  Fix it by changing
the order.

[andreyknvl@google.com: fix compilation error when CONFIG_SLUB_DEBUG=n]
  Link: http://lkml.kernel.org/r/ac27cc0bbaeb414ed77bcd6671a877cf3546d56e.1550066133.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/cd895d627465a3f1c712647072d17f10883be2a1.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
a2f775751d kmemleak: account for tagged pointers when calculating pointer range 
kmemleak keeps two global variables, min_addr and max_addr, which store
the range of valid (encountered by kmemleak) pointer values, which it
later uses to speed up pointer lookup when scanning blocks.

With tagged pointers this range will get bigger than it needs to be.  This
patch makes kmemleak untag pointers before saving them to min_addr and
max_addr and when performing a lookup.

Link: http://lkml.kernel.org/r/16e887d442986ab87fe87a755815ad92fa431a5f.1550066133.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Qian Cai <cai@lca.pw>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
53128245b4 kasan, kmemleak: pass tagged pointers to kmemleak 
Right now we call kmemleak hooks before assigning tags to pointers in
KASAN hooks.  As a result, when an objects gets allocated, kmemleak sees a
differently tagged pointer, compared to the one it sees when the object
gets freed.  Fix it by calling KASAN hooks before kmemleak's ones.

Link: http://lkml.kernel.org/r/cd825aa4897b0fc37d3316838993881daccbe9f5.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Andrey Konovalov
e1db95befb kasan: fix assigning tags twice 
When an object is kmalloc()'ed, two hooks are called: kasan_slab_alloc()
and kasan_kmalloc().  Right now we assign a tag twice, once in each of the
hooks.  Fix it by assigning a tag only in the former hook.

Link: http://lkml.kernel.org/r/ce8c6431da735aa7ec051fd6497153df690eb021.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:01:00 -08:00
Ralph Campbell
050c17f239 numa: change get_mempolicy() to use nr_node_ids instead of MAX_NUMNODES 
The system call, get_mempolicy() [1], passes an unsigned long *nodemask
pointer and an unsigned long maxnode argument which specifies the length
of the user's nodemask array in bits (which is rounded up).  The manual
page says that if the maxnode value is too small, get_mempolicy will
return EINVAL but there is no system call to return this minimum value.
To determine this value, some programs search /proc/<pid>/status for a
line starting with "Mems_allowed:" and use the number of digits in the
mask to determine the minimum value.  A recent change to the way this line
is formatted [2] causes these programs to compute a value less than
MAX_NUMNODES so get_mempolicy() returns EINVAL.

Change get_mempolicy(), the older compat version of get_mempolicy(), and
the copy_nodes_to_user() function to use nr_node_ids instead of
MAX_NUMNODES, thus preserving the defacto method of computing the minimum
size for the nodemask array and the maxnode argument.

[1] http://man7.org/linux/man-pages/man2/get_mempolicy.2.html
[2] https://lore.kernel.org/lkml/1545405631-6808-1-git-send-email-longman@redhat.com

Link: http://lkml.kernel.org/r/20190211180245.22295-1-rcampbell@nvidia.com
Fixes: 4fb8e5b89bcbbbb ("include/linux/nodemask.h: use nr_node_ids (not MAX_NUMNODES) in __nodemask_pr_numnodes()")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Suggested-by: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-21 09:00:59 -08:00
Linus Torvalds
40e196a906 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 
Pull networking fixes from David Miller:

 1) Fix suspend and resume in mt76x0u USB driver, from Stanislaw
    Gruszka.

 2) Missing memory barriers in xsk, from Magnus Karlsson.

 3) rhashtable fixes in mac80211 from Herbert Xu.

 4) 32-bit MIPS eBPF JIT fixes from Paul Burton.

 5) Fix for_each_netdev_feature() on big endian, from Hauke Mehrtens.

 6) GSO validation fixes from Willem de Bruijn.

 7) Endianness fix for dwmac4 timestamp handling, from Alexandre Torgue.

 8) More strict checks in tcp_v4_err(), from Eric Dumazet.

 9) af_alg_release should NULL out the sk after the sock_put(), from Mao
    Wenan.

10) Missing unlock in mac80211 mesh error path, from Wei Yongjun.

11) Missing device put in hns driver, from Salil Mehta.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (44 commits)
  sky2: Increase D3 delay again
  vhost: correctly check the return value of translate_desc() in log_used()
  net: netcp: Fix ethss driver probe issue
  net: hns: Fixes the missing put_device in positive leg for roce reset
  net: stmmac: Fix a race in EEE enable callback
  qed: Fix iWARP syn packet mac address validation.
  qed: Fix iWARP buffer size provided for syn packet processing.
  r8152: Add support for MAC address pass through on RTL8153-BD
  mac80211: mesh: fix missing unlock on error in table_path_del()
  net/mlx4_en: fix spelling mistake: "quiting" -> "quitting"
  net: crypto set sk to NULL when af_alg_release.
  net: Do not allocate page fragments that are not skb aligned
  mm: Use fixed constant in page_frag_alloc instead of size + 1
  tcp: tcp_v4_err() should be more careful
  tcp: clear icsk_backoff in tcp_write_queue_purge()
  net: mv643xx_eth: disable clk on error path in mv643xx_eth_shared_probe()
  qmi_wwan: apply SET_DTR quirk to Sierra WP7607
  net: stmmac: handle endianness in dwmac4_get_timestamp
  doc: Mention MSG_ZEROCOPY implementation for UDP
  mlxsw: __mlxsw_sp_port_headroom_set(): Fix a use of local variable
  ...
 2019-02-19 16:13:19 -08:00
Alexander Duyck
8644772637 mm: Use fixed constant in page_frag_alloc instead of size + 1 
This patch replaces the size + 1 value introduced with the recent fix for 1
byte allocs with a constant value.

The idea here is to reduce code overhead as the previous logic would have
to read size into a register, then increment it, and write it back to
whatever field was being used. By using a constant we can avoid those
memory reads and arithmetic operations in favor of just encoding the
maximum value into the operation itself.

Fixes: 2c2ade8174 ("mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs")
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 2019-02-17 15:48:43 -08:00
Ard Biesheuvel
8a5b403d71 arm64, mm, efi: Account for GICv3 LPI tables in static memblock reserve table 
In the irqchip and EFI code, we have what basically amounts to a quirk
to work around a peculiarity in the GICv3 architecture, which permits
the system memory address of LPI tables to be programmable only once
after a CPU reset. This means kexec kernels must use the same memory
as the first kernel, and thus ensure that this memory has not been
given out for other purposes by the time the ITS init code runs, which
is not very early for secondary CPUs.

On systems with many CPUs, these reservations could overflow the
memblock reservation table, and this was addressed in commit:

  eff8962888 ("efi/arm: Defer persistent reservations until after paging_init()")

However, this turns out to have made things worse, since the allocation
of page tables and heap space for the resized memblock reservation table
itself may overwrite the regions we are attempting to reserve, which may
cause all kinds of corruption, also considering that the ITS will still
be poking bits into that memory in response to incoming MSIs.

So instead, let's grow the static memblock reservation table on such
systems so it can accommodate these reservations at an earlier time.
This will permit us to revert the above commit in a subsequent patch.

[ mingo: Minor cleanups. ]

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190215123333.21209-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2019-02-16 15:02:03 +01:00
Linus Torvalds
6e7bd3b549 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 
Pull networking fixes from David Miller:

 1) Fix MAC address setting in mac80211 pmsr code, from Johannes Berg.

 2) Probe SFP modules after being attached, from Russell King.

 3) Byte ordering bug in SMC rx_curs_confirmed code, from Ursula Braun.

 4) Revert some r8169 changes that are causing regressions, from Heiner
    Kallweit.

 5) Fix spurious connection timeouts in netfilter nat code, from Florian
    Westphal.

 6) SKB leak in tipc, from Hoang Le.

 7) Short packet checkum issue in mlx4, similar to a previous mlx5
    change, from Saeed Mahameed. The issue is that whilst padding bytes
    are usually zero, it is not guarateed and the hardware doesn't take
    the padding bytes into consideration when generating the checksum.

 8) Fix various races in cls_tcindex, from Cong Wang.

 9) Need to set stream ext to NULL before freeing in SCTP code, from Xin
    Long.

10) Fix locking in phy_is_started, from Heiner Kallweit.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (54 commits)
  net: ethernet: freescale: set FEC ethtool regs version
  net: hns: Fix object reference leaks in hns_dsaf_roce_reset()
  mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs
  net: phy: fix potential race in the phylib state machine
  net: phy: don't use locking in phy_is_started
  selftests: fix timestamping Makefile
  net: dsa: bcm_sf2: potential array overflow in bcm_sf2_sw_suspend()
  net: fix possible overflow in __sk_mem_raise_allocated()
  dsa: mv88e6xxx: Ensure all pending interrupts are handled prior to exit
  net: phy: fix interrupt handling in non-started states
  sctp: set stream ext to NULL after freeing it in sctp_stream_outq_migrate
  sctp: call gso_reset_checksum when computing checksum in sctp_gso_segment
  net/mlx5e: XDP, fix redirect resources availability check
  net/mlx5: Fix a compilation warning in events.c
  net/mlx5: No command allowed when command interface is not ready
  net/mlx5e: Fix NULL pointer derefernce in set channels error flow
  netfilter: nft_compat: use-after-free when deleting targets
  team: avoid complex list operations in team_nl_cmd_options_set()
  net_sched: fix two more memory leaks in cls_tcindex
  net_sched: fix a memory leak in cls_tcindex
  ...
 2019-02-15 08:00:11 -08:00
Jann Horn
2c2ade8174 mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs 
The basic idea behind ->pagecnt_bias is: If we pre-allocate the maximum
number of references that we might need to create in the fastpath later,
the bump-allocation fastpath only has to modify the non-atomic bias value
that tracks the number of extra references we hold instead of the atomic
refcount. The maximum number of allocations we can serve (under the
assumption that no allocation is made with size 0) is nc->size, so that's
the bias used.

However, even when all memory in the allocation has been given away, a
reference to the page is still held; and in the `offset < 0` slowpath, the
page may be reused if everyone else has dropped their references.
This means that the necessary number of references is actually
`nc->size+1`.

Luckily, from a quick grep, it looks like the only path that can call
page_frag_alloc(fragsz=1) is TAP with the IFF_NAPI_FRAGS flag, which
requires CAP_NET_ADMIN in the init namespace and is only intended to be
used for kernel testing and fuzzing.

To test for this issue, put a `WARN_ON(page_ref_count(page) == 0)` in the
`offset < 0` path, below the virt_to_page() call, and then repeatedly call
writev() on a TAP device with IFF_TAP|IFF_NO_PI|IFF_NAPI_FRAGS|IFF_NAPI,
with a vector consisting of 15 elements containing 1 byte each.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 2019-02-14 12:12:17 -05:00
Qian Cai
2f1ee0913c Revert "mm: use early_pfn_to_nid in page_ext_init" 
This reverts commit fe53ca5427 ("mm: use early_pfn_to_nid in
page_ext_init").

When booting a system with "page_owner=on",

start_kernel
  page_ext_init
    invoke_init_callbacks
      init_section_page_ext
        init_page_owner
          init_early_allocated_pages
            init_zones_in_node
              init_pages_in_zone
                lookup_page_ext
                  page_to_nid

The issue here is that page_to_nid() will not work since some page flags
have no node information until later in page_alloc_init_late() due to
DEFERRED_STRUCT_PAGE_INIT.  Hence, it could trigger an out-of-bounds
access with an invalid nid.

  UBSAN: Undefined behaviour in ./include/linux/mm.h:1104:50
  index 7 is out of range for type 'zone [5]'

Also, kernel will panic since flags were poisoned earlier with,

CONFIG_DEBUG_VM_PGFLAGS=y
CONFIG_NODE_NOT_IN_PAGE_FLAGS=n

start_kernel
  setup_arch
    pagetable_init
      paging_init
        sparse_init
          sparse_init_nid
            memblock_alloc_try_nid_raw

It did not handle it well in init_pages_in_zone() which ends up calling
page_to_nid().

  page:ffffea0004200000 is uninitialized and poisoned
  raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
  raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
  page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
  page_owner info is not active (free page?)
  kernel BUG at include/linux/mm.h:990!
  RIP: 0010:init_page_owner+0x486/0x520

This means that assumptions behind commit fe53ca5427 ("mm: use
early_pfn_to_nid in page_ext_init") are incomplete.  Therefore, revert
the commit for now.  A proper way to move the page_owner initialization
to sooner is to hook into memmap initialization.

Link: http://lkml.kernel.org/r/20190115202812.75820-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-12 16:33:18 -08:00
Yu Zhao
414fd080d1 mm/gup: fix gup_pmd_range() for dax 
For dax pmd, pmd_trans_huge() returns false but pmd_huge() returns true
on x86.  So the function works as long as hugetlb is configured.
However, dax doesn't depend on hugetlb.

Link: http://lkml.kernel.org/r/20190111034033.601-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-12 16:33:18 -08:00
Dave Chinner
a9a238e83f Revert "mm: slowly shrink slabs with a relatively small number of objects" 
This reverts commit 172b06c32b ("mm: slowly shrink slabs with a
relatively small number of objects").

This change changes the agressiveness of shrinker reclaim, causing small
cache and low priority reclaim to greatly increase scanning pressure on
small caches.  As a result, light memory pressure has a disproportionate
affect on small caches, and causes large caches to be reclaimed much
faster than previously.

As a result, it greatly perturbs the delicate balance of the VFS caches
(dentry/inode vs file page cache) such that the inode/dentry caches are
reclaimed much, much faster than the page cache and this drives us into
several other caching imbalance related problems.

As such, this is a bad change and needs to be reverted.

[ Needs some massaging to retain the later seekless shrinker
  modifications.]

Link: http://lkml.kernel.org/r/20190130041707.27750-3-david@fromorbit.com
Fixes: 172b06c32b ("mm: slowly shrink slabs with a relatively small number of objects")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Cc: Wolfgang Walter <linux@stwm.de>
Cc: Roman Gushchin <guro@fb.com>
Cc: Spock <dairinin@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-12 16:33:18 -08:00
David Hildenbrand
e0a352fabc mm: migrate: don't rely on __PageMovable() of newpage after unlocking it 
We had a race in the old balloon compaction code before b1123ea6d3
("mm: balloon: use general non-lru movable page feature") refactored it
that became visible after backporting 195a8c43e9 ("virtio-balloon:
deflate via a page list") without the refactoring.

The bug existed from commit d6d86c0a7f ("mm/balloon_compaction:
redesign ballooned pages management") till b1123ea6d3 ("mm: balloon:
use general non-lru movable page feature").  d6d86c0a7f
("mm/balloon_compaction: redesign ballooned pages management") was
backported to 3.12, so the broken kernels are stable kernels [3.12 -
4.7].

There was a subtle race between dropping the page lock of the newpage in
__unmap_and_move() and checking for __is_movable_balloon_page(newpage).

Just after dropping this page lock, virtio-balloon could go ahead and
deflate the newpage, effectively dequeueing it and clearing PageBalloon,
in turn making __is_movable_balloon_page(newpage) fail.

This resulted in dropping the reference of the newpage via
putback_lru_page(newpage) instead of put_page(newpage), leading to
page->lru getting modified and a !LRU page ending up in the LRU lists.
With 195a8c43e9 ("virtio-balloon: deflate via a page list")
backported, one would suddenly get corrupted lists in
release_pages_balloon():

- WARNING: CPU: 13 PID: 6586 at lib/list_debug.c:59 __list_del_entry+0xa1/0xd0
- list_del corruption. prev->next should be ffffe253961090a0, but was dead000000000100

Nowadays this race is no longer possible, but it is hidden behind very
ugly handling of __ClearPageMovable() and __PageMovable().

__ClearPageMovable() will not make __PageMovable() fail, only
PageMovable().  So the new check (__PageMovable(newpage)) will still
hold even after newpage was dequeued by virtio-balloon.

If anybody would ever change that special handling, the BUG would be
introduced again.  So instead, make it explicit and use the information
of the original isolated page before migration.

This patch can be backported fairly easy to stable kernels (in contrast
to the refactoring).

Link: http://lkml.kernel.org/r/20190129233217.10747-1-david@redhat.com
Fixes: d6d86c0a7f ("mm/balloon_compaction: redesign ballooned pages management")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Vratislav Bendel <vbendel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vratislav Bendel <vbendel@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>	[3.12 - 4.7]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:24 -08:00
Michal Hocko
e3df4c6e48 mm, memory_hotplug: __offline_pages fix wrong locking 
Jan has noticed that we do double unlock on some failure paths when
offlining a page range.  This is indeed the case when
test_pages_in_a_zone respp.  start_isolate_page_range fail.  This was an
omission when forward porting the debugging patch from an older kernel.

Fix the issue by dropping mem_hotplug_done from the failure condition
and keeping the single unlock in the catch all failure path.

Link: http://lkml.kernel.org/r/20190115120307.22768-1-mhocko@kernel.org
Fixes: 7960509329 ("mm, memory_hotplug: print reason for the offlining failure")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Tested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Naoya Horiguchi
6376360ecb mm: hwpoison: use do_send_sig_info() instead of force_sig() 
Currently memory_failure() is racy against process's exiting, which
results in kernel crash by null pointer dereference.

The root cause is that memory_failure() uses force_sig() to forcibly
kill asynchronous (meaning not in the current context) processes.  As
discussed in thread https://lkml.org/lkml/2010/6/8/236 years ago for OOM
fixes, this is not a right thing to do.  OOM solves this issue by using
do_send_sig_info() as done in commit d2d393099d ("signal:
oom_kill_task: use SEND_SIG_FORCED instead of force_sig()"), so this
patch is suggesting to do the same for hwpoison.  do_send_sig_info()
properly accesses to siglock with lock_task_sighand(), so is free from
the reported race.

I confirmed that the reported bug reproduces with inserting some delay
in kill_procs(), and it never reproduces with this patch.

Note that memory_failure() can send another type of signal using
force_sig_mceerr(), and the reported race shouldn't happen on it because
force_sig_mceerr() is called only for synchronous processes (i.e.
BUS_MCEERR_AR happens only when some process accesses to the corrupted
memory.)

Link: http://lkml.kernel.org/r/20190116093046.GA29835@hori1.linux.bs1.fc.nec.co.jp
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Anders Roxell
0d0c8de878 kasan: mark file common so ftrace doesn't trace it 
When option CONFIG_KASAN is enabled toghether with ftrace, function
ftrace_graph_caller() gets in to a recursion, via functions
kasan_check_read() and kasan_check_write().

 Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
 179             mcount_get_pc             x0    //     function's pc
 (gdb) bt
 #0  ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
 #1  0xffffff90101406c8 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151
 #2  0xffffff90106fd084 in kasan_check_write (p=0xffffffc06c170878, size=4) at ../mm/kasan/common.c:105
 #3  0xffffff90104a2464 in atomic_add_return (v=<optimized out>, i=<optimized out>) at ./include/generated/atomic-instrumented.h:71
 #4  atomic_inc_return (v=<optimized out>) at ./include/generated/atomic-fallback.h:284
 #5  trace_graph_entry (trace=0xffffffc03f5ff380) at ../kernel/trace/trace_functions_graph.c:441
 #6  0xffffff9010481774 in trace_graph_entry_watchdog (trace=<optimized out>) at ../kernel/trace/trace_selftest.c:741
 #7  0xffffff90104a185c in function_graph_enter (ret=<optimized out>, func=<optimized out>, frame_pointer=18446743799894897728, retp=<optimized out>) at ../kernel/trace/trace_functions_graph.c:196
 #8  0xffffff9010140628 in prepare_ftrace_return (self_addr=18446743592948977792, parent=0xffffffc03f5ff418, frame_pointer=18446743799894897728) at ../arch/arm64/kernel/ftrace.c:231
 #9  0xffffff90101406f4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182
 Backtrace stopped: previous frame identical to this frame (corrupt stack?)
 (gdb)

Rework so that the kasan implementation isn't traced.

Link: http://lkml.kernel.org/r/20181212183447.15890-1-anders.roxell@linaro.org
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Shakeel Butt
cefc7ef3c8 mm, oom: fix use-after-free in oom_kill_process 
Syzbot instance running on upstream kernel found a use-after-free bug in
oom_kill_process.  On further inspection it seems like the process
selected to be oom-killed has exited even before reaching
read_lock(&tasklist_lock) in oom_kill_process().  More specifically the
tsk->usage is 1 which is due to get_task_struct() in oom_evaluate_task()
and the put_task_struct within for_each_thread() frees the tsk and
for_each_thread() tries to access the tsk.  The easiest fix is to do
get/put across the for_each_thread() on the selected task.

Now the next question is should we continue with the oom-kill as the
previously selected task has exited? However before adding more
complexity and heuristics, let's answer why we even look at the children
of oom-kill selected task? The select_bad_process() has already selected
the worst process in the system/memcg.  Due to race, the selected
process might not be the worst at the kill time but does that matter?
The userspace can use the oom_score_adj interface to prefer children to
be killed before the parent.  I looked at the history but it seems like
this is there before git history.

Link: http://lkml.kernel.org/r/20190121215850.221745-1-shakeelb@google.com
Reported-by: syzbot+7fbbfa368521945f0e3d@syzkaller.appspotmail.com
Fixes: 6b0c81b3be ("mm, oom: reduce dependency on tasklist_lock")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Oscar Salvador
eeb0efd071 mm,memory_hotplug: fix scan_movable_pages() for gigantic hugepages 
This is the same sort of error we saw in commit 17e2e7d7e1 ("mm,
page_alloc: fix has_unmovable_pages for HugePages").

Gigantic hugepages cross several memblocks, so it can be that the page
we get in scan_movable_pages() is a page-tail belonging to a
1G-hugepage.  If that happens, page_hstate()->size_to_hstate() will
return NULL, and we will blow up in hugepage_migration_supported().

The splat is as follows:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  #PF error: [normal kernel read fault]
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP PTI
  CPU: 1 PID: 1350 Comm: bash Tainted: G            E     5.0.0-rc1-mm1-1-default+ #27
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
  RIP: 0010:__offline_pages+0x6ae/0x900
  Call Trace:
   memory_subsys_offline+0x42/0x60
   device_offline+0x80/0xa0
   state_store+0xab/0xc0
   kernfs_fop_write+0x102/0x180
   __vfs_write+0x26/0x190
   vfs_write+0xad/0x1b0
   ksys_write+0x42/0x90
   do_syscall_64+0x5b/0x180
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  Modules linked in: af_packet(E) xt_tcpudp(E) ipt_REJECT(E) xt_conntrack(E) nf_conntrack(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) bridge(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) iptable_filter(E) ip_tables(E) x_tables(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) bochs_drm(E) ttm(E) aesni_intel(E) drm_kms_helper(E) aes_x86_64(E) crypto_simd(E) cryptd(E) glue_helper(E) drm(E) virtio_net(E) syscopyarea(E) sysfillrect(E) net_failover(E) sysimgblt(E) pcspkr(E) failover(E) i2c_piix4(E) fb_sys_fops(E) parport_pc(E) parport(E) button(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) xxhash(E) raid6_pq(E) sd_mod(E) ata_generic(E) ata_piix(E) ahci(E) libahci(E) libata(E) crc32c_intel(E) serio_raw(E) virtio_pci(E) virtio_ring(E) virtio(E) sg(E) scsi_mod(E) autofs4(E)

[akpm@linux-foundation.org: fix brace layout, per David.  Reduce indentation]
Link: http://lkml.kernel.org/r/20190122154407.18417-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Mikhail Zaslonko
24feb47c5f mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone 
If memory end is not aligned with the sparse memory section boundary,
the mapping of such a section is only partly initialized.  This may lead
to VM_BUG_ON due to uninitialized struct pages access from
test_pages_in_a_zone() function triggered by memory_hotplug sysfs
handlers.

Here are the the panic examples:
 CONFIG_DEBUG_VM_PGFLAGS=y
 kernel parameter mem=2050M
 --------------------------
 page:000003d082008000 is uninitialized and poisoned
 page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
 Call Trace:
   test_pages_in_a_zone+0xde/0x160
   show_valid_zones+0x5c/0x190
   dev_attr_show+0x34/0x70
   sysfs_kf_seq_show+0xc8/0x148
   seq_read+0x204/0x480
   __vfs_read+0x32/0x178
   vfs_read+0x82/0x138
   ksys_read+0x5a/0xb0
   system_call+0xdc/0x2d8
 Last Breaking-Event-Address:
   test_pages_in_a_zone+0xde/0x160
 Kernel panic - not syncing: Fatal exception: panic_on_oops

Fix this by checking whether the pfn to check is within the zone.

[mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com]
Link: http://lkml.kernel.org/r/20190128144506.15603-3-mhocko@kernel.org

[mhocko@suse.com: separated this change from
http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Michal Hocko
efad4e475c mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone 
Patch series "mm, memory_hotplug: fix uninitialized pages fallouts", v2.

Mikhail Zaslonko has posted fixes for the two bugs quite some time ago
[1].  I have pushed back on those fixes because I believed that it is
much better to plug the problem at the initialization time rather than
play whack-a-mole all over the hotplug code and find all the places
which expect the full memory section to be initialized.

We have ended up with commit 2830bf6f05 ("mm, memory_hotplug:
initialize struct pages for the full memory section") merged and cause a
regression [2][3].  The reason is that there might be memory layouts
when two NUMA nodes share the same memory section so the merged fix is
simply incorrect.

In order to plug this hole we really have to be zone range aware in
those handlers.  I have split up the original patch into two.  One is
unchanged (patch 2) and I took a different approach for `removable'
crash.

[1] http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1666948
[3] http://lkml.kernel.org/r/20190125163938.GA20411@dhcp22.suse.cz

This patch (of 2):

Mikhail has reported the following VM_BUG_ON triggered when reading sysfs
removable state of a memory block:

 page:000003d08300c000 is uninitialized and poisoned
 page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
 Call Trace:
   is_mem_section_removable+0xb4/0x190
   show_mem_removable+0x9a/0xd8
   dev_attr_show+0x34/0x70
   sysfs_kf_seq_show+0xc8/0x148
   seq_read+0x204/0x480
   __vfs_read+0x32/0x178
   vfs_read+0x82/0x138
   ksys_read+0x5a/0xb0
   system_call+0xdc/0x2d8
 Last Breaking-Event-Address:
   is_mem_section_removable+0xb4/0x190
 Kernel panic - not syncing: Fatal exception: panic_on_oops

The reason is that the memory block spans the zone boundary and we are
stumbling over an unitialized struct page.  Fix this by enforcing zone
range in is_mem_section_removable so that we never run away from a zone.

Link: http://lkml.kernel.org/r/20190128144506.15603-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Debugged-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Tetsuo Handa
9bcdeb51bd oom, oom_reaper: do not enqueue same task twice 
Arkadiusz reported that enabling memcg's group oom killing causes
strange memcg statistics where there is no task in a memcg despite the
number of tasks in that memcg is not 0.  It turned out that there is a
bug in wake_oom_reaper() which allows enqueuing same task twice which
makes impossible to decrease the number of tasks in that memcg due to a
refcount leak.

This bug existed since the OOM reaper became invokable from
task_will_free_mem(current) path in out_of_memory() in Linux 4.7,

  T1@P1     |T2@P1     |T3@P1     |OOM reaper
  ----------+----------+----------+------------
                                   # Processing an OOM victim in a different memcg domain.
                        try_charge()
                          mem_cgroup_out_of_memory()
                            mutex_lock(&oom_lock)
             try_charge()
               mem_cgroup_out_of_memory()
                 mutex_lock(&oom_lock)
  try_charge()
    mem_cgroup_out_of_memory()
      mutex_lock(&oom_lock)
                            out_of_memory()
                              oom_kill_process(P1)
                                do_send_sig_info(SIGKILL, @P1)
                                mark_oom_victim(T1@P1)
                                wake_oom_reaper(T1@P1) # T1@P1 is enqueued.
                            mutex_unlock(&oom_lock)
                 out_of_memory()
                   mark_oom_victim(T2@P1)
                   wake_oom_reaper(T2@P1) # T2@P1 is enqueued.
                 mutex_unlock(&oom_lock)
      out_of_memory()
        mark_oom_victim(T1@P1)
        wake_oom_reaper(T1@P1) # T1@P1 is enqueued again due to oom_reaper_list == T2@P1 && T1@P1->oom_reaper_list == NULL.
      mutex_unlock(&oom_lock)
                                   # Completed processing an OOM victim in a different memcg domain.
                                   spin_lock(&oom_reaper_lock)
                                   # T1P1 is dequeued.
                                   spin_unlock(&oom_reaper_lock)

but memcg's group oom killing made it easier to trigger this bug by
calling wake_oom_reaper() on the same task from one out_of_memory()
request.

Fix this bug using an approach used by commit 855b018325 ("oom,
oom_reaper: disable oom_reaper for oom_kill_allocating_task").  As a
side effect of this patch, this patch also avoids enqueuing multiple
threads sharing memory via task_will_free_mem(current) path.

Link: http://lkml.kernel.org/r/e865a044-2c10-9858-f4ef-254bc71d6cc2@i-love.sakura.ne.jp
Link: http://lkml.kernel.org/r/5ee34fc6-1485-34f8-8790-903ddabaa809@i-love.sakura.ne.jp
Fixes: af8e15cc85 ("oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Tested-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Aleksa Sarai <asarai@suse.de>
Cc: Jay Kamat <jgkamat@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Jan Kara
80409c65e2 mm: migrate: make buffer_migrate_page_norefs() actually succeed 
Currently, buffer_migrate_page_norefs() was constantly failing because
buffer_migrate_lock_buffers() grabbed reference on each buffer.  In
fact, there's no reason for buffer_migrate_lock_buffers() to grab any
buffer references as the page is locked during all our operation and
thus nobody can reclaim buffers from the page.

So remove grabbing of buffer references which also makes
buffer_migrate_page_norefs() succeed.

Link: http://lkml.kernel.org/r/20190116131217.7226-1-jack@suse.cz
Fixes: 89cb0888ca "mm: migrate: provide buffer_migrate_page_norefs()"
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Andrea Arcangeli
1ac25013fb mm/hugetlb.c: teach follow_hugetlb_page() to handle FOLL_NOWAIT 
hugetlb needs the same fix as faultin_nopage (which was applied in
commit 96312e6128 ("mm/gup.c: teach get_user_pages_unlocked to handle
FOLL_NOWAIT")) or KVM hangs because it thinks the mmap_sem was already
released by hugetlb_fault() if it returned VM_FAULT_RETRY, but it wasn't
in the FOLL_NOWAIT case.

Link: http://lkml.kernel.org/r/20190109020203.26669-2-aarcange@redhat.com
Fixes: ce53053ce3 ("kvm: switch get_user_page_nowait() to get_user_pages_unlocked()")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:23 -08:00
Oscar Salvador
1723058eab mm, memory_hotplug: don't bail out in do_migrate_range() prematurely 
do_migrate_range() takes a memory range and tries to isolate the pages
to put them into a list.  This list will be later on used in
migrate_pages() to know the pages we need to migrate.

Currently, if we fail to isolate a single page, we put all already
isolated pages back to their LRU and we bail out from the function.
This is quite suboptimal, as this will force us to start over again
because scan_movable_pages will give us the same range.  If there is no
chance that we can isolate that page, we will loop here forever.

Issue debugged in [1] has proved that.  During the debugging of that
issue, it was noticed that if do_migrate_ranges() fails to isolate a
single page, we will just discard the work we have done so far and bail
out, which means that scan_movable_pages() will find again the same set
of pages.

Instead, we can just skip the error, keep isolating as much pages as
possible and then proceed with the call to migrate_pages().

This will allow us to do as much work as possible at once.

[1] https://lkml.org/lkml/2018/12/6/324

Michal said:

: I still think that this doesn't give us a whole picture.  Looping for
: ever is a bug.  Failing the isolation is quite possible and it should
: be a ephemeral condition (e.g.  a race with freeing the page or
: somebody else isolating the page for whatever reason).  And here comes
: the disadvantage of the current implementation.  We simply throw
: everything on the floor just because of a ephemeral condition.  The
: racy page_count check is quite dubious to prevent from that.

Link: http://lkml.kernel.org/r/20181211135312.27034-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-02-01 15:46:22 -08:00
Michal Hocko
4aa9fc2a43 Revert "mm, memory_hotplug: initialize struct pages for the full memory section" 
This reverts commit 2830bf6f05.

The underlying assumption that one sparse section belongs into a single
numa node doesn't hold really. Robert Shteynfeld has reported a boot
failure. The boot log was not captured but his memory layout is as
follows:

  Early memory node ranges
    node   1: [mem 0x0000000000001000-0x0000000000090fff]
    node   1: [mem 0x0000000000100000-0x00000000dbdf8fff]
    node   1: [mem 0x0000000100000000-0x0000001423ffffff]
    node   0: [mem 0x0000001424000000-0x0000002023ffffff]

This means that node0 starts in the middle of a memory section which is
also in node1.  memmap_init_zone tries to initialize padding of a
section even when it is outside of the given pfn range because there are
code paths (e.g.  memory hotplug) which assume that the full worth of
memory section is always initialized.

In this particular case, though, such a range is already intialized and
most likely already managed by the page allocator.  Scribbling over
those pages corrupts the internal state and likely blows up when any of
those pages gets used.

Reported-by: Robert Shteynfeld <robert.shteynfeld@gmail.com>
Fixes: 2830bf6f05 ("mm, memory_hotplug: initialize struct pages for the full memory section")
Cc: stable@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-01-28 10:35:22 -08:00
Linus Torvalds
6b8f915916 for-linus-20190125 
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Merge tag 'for-linus-20190125' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "A collection of fixes for this release. This contains:

   - Silence sparse rightfully complaining about non-static wbt
     functions (Bart)

   - Fixes for the zoned comments/ioctl documentation (Damien)

   - direct-io fix that's been lingering for a while (Ernesto)

   - cgroup writeback fix (Tejun)

   - Set of NVMe patches for nvme-rdma/tcp (Sagi, Hannes, Raju)

   - Block recursion tracking fix (Ming)

   - Fix debugfs command flag naming for a few flags (Jianchao)"

* tag 'for-linus-20190125' of git://git.kernel.dk/linux-block:
  block: Fix comment typo
  uapi: fix ioctl documentation
  blk-wbt: Declare local functions static
  blk-mq: fix the cmd_flag_name array
  nvme-multipath: drop optimization for static ANA group IDs
  nvmet-rdma: fix null dereference under heavy load
  nvme-rdma: rework queue maps handling
  nvme-tcp: fix timeout handler
  nvme-rdma: fix timeout handler
  writeback: synchronize sync(2) against cgroup writeback membership switches
  block: cover another queue enter recursion via BIO_QUEUE_ENTERED
  direct-io: allow direct writes to empty inodes
 2019-01-26 12:42:41 -08:00
Linus Torvalds
30bac164ac Revert "Change mincore() to count "mapped" pages rather than "cached" pages" 
This reverts commit 574823bfab.

It turns out that my hope that we could just remove the code that
exposes the cache residency status from mincore() was too optimistic.

There are various random users that want it, and one example would be
the Netflix database cluster maintenance. To quote Josh Snyder:

 "For Netflix, losing accurate information from the mincore syscall
  would lengthen database cluster maintenance operations from days to
  months. We rely on cross-process mincore to migrate the contents of a
  page cache from machine to machine, and across reboots.

  To do this, I wrote and maintain happycache [1], a page cache
  dumper/loader tool. It is quite similar in architecture to pgfincore,
  except that it is agnostic to workload. The gist of happycache's
  operation is "produce a dump of residence status for each page, do
  some operation, then reload exactly the same pages which were present
  before." happycache is entirely dependent on accurate reporting of the
  in-core status of file-backed pages, as accessed by another process.

  We primarily use happycache with Cassandra, which (like Postgres +
  pgfincore) relies heavily on OS page cache to reduce disk accesses.
  Because our workloads never experience a cold page cache, we are able
  to provision hardware for a peak utilization level that is far lower
  than the hypothetical "every query is a cache miss" peak.

  A database warmed by happycache can be ready for service in seconds
  (bounded only by the performance of the drives and the I/O subsystem),
  with no period of in-service degradation. By contrast, putting a
  database in service without a page cache entails a potentially
  unbounded period of degradation (at Netflix, the time to populate a
  single node's cache via natural cache misses varies by workload from
  hours to weeks). If a single node upgrade were to take weeks, then
  upgrading an entire cluster would take months. Since we want to apply
  security upgrades (and other things) on a somewhat tighter schedule,
  we would have to develop more complex solutions to provide the same
  functionality already provided by mincore.

  At the bottom line, happycache is designed to benignly exploit the
  same information leak documented in the paper [2]. I think it makes
  perfect sense to remove cross-process mincore functionality from
  unprivileged users, but not to remove it entirely"

We do have an alternate approach that limits the cache residency
reporting only to processes that have write permissions to the file, so
we can fix the original information leak issue that way.  It involves
_adding_ code rather than removing it, which is sad, but hey, at least
we haven't found any users that would find the restrictions
unacceptable.

So revert the optimistic first approach to make room for that alternate
fix instead.

Reported-by: Josh Snyder <joshs@netflix.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Kevin Easton <kevin@guarana.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Cyril Hrubis <chrubis@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Daniel Gruss <daniel@gruss.cc>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-01-24 09:04:37 +13:00
Tejun Heo
7fc5854f8c writeback: synchronize sync(2) against cgroup writeback membership switches 
sync_inodes_sb() can race against cgwb (cgroup writeback) membership
switches and fail to writeback some inodes.  For example, if an inode
switches to another wb while sync_inodes_sb() is in progress, the new
wb might not be visible to bdi_split_work_to_wbs() at all or the inode
might jump from a wb which hasn't issued writebacks yet to one which
already has.

This patch adds backing_dev_info->wb_switch_rwsem to synchronize cgwb
switch path against sync_inodes_sb() so that sync_inodes_sb() is
guaranteed to see all the target wbs and inodes can't jump wbs to
escape syncing.

v2: Fixed misplaced rwsem init.  Spotted by Jiufei.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jiufei Xue <xuejiufei@gmail.com>
Link: http://lkml.kernel.org/r/dc694ae2-f07f-61e1-7097-7c8411cee12d@gmail.com
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2019-01-22 14:39:38 -07:00
Sean Christopherson
ba42273131 mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one 
The conversion to use a structure for mmu_notifier_invalidate_range_*()
unintentionally changed the usage in try_to_unmap_one() to init the
'struct mmu_notifier_range' with vma->vm_start instead of @address,
i.e. it invalidates the wrong address range.  Revert to the correct
address range.

Manifests as KVM use-after-free WARNINGs and subsequent "BUG: Bad page
state in process X" errors when reclaiming from a KVM guest due to KVM
removing the wrong pages from its own mappings.

Reported-by: leozinho29_eu@hotmail.com
Reported-by: Mike Galbraith <efault@gmx.de>
Reported-and-tested-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Pankaj gupta <pagupta@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: ac46d4f3c4 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-01-10 02:58:21 -08:00