Commit Graph

11950 Commits

Author SHA1 Message Date
Linus Torvalds
9682b3dea2 Merge branch 'for-linus' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina:
 "The usual rocket-science from trivial tree for 4.15"

* 'for-linus' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  MAINTAINERS: relinquish kconfig
  MAINTAINERS: Update my email address
  treewide: Fix typos in Kconfig
  kfifo: Fix comments
  init/Kconfig: Fix module signing document location
  misc: ibmasm: Return error on error path
  HID: logitech-hidpp: fix mistake in printk, "feeback" -> "feedback"
  MAINTAINERS: Correct path to uDraw PS3 driver
  tracing: Fix doc mistakes in trace sample
  tracing: Kconfig text fixes for CONFIG_HWLAT_TRACER
  MIPS: Alchemy: Remove reverted CONFIG_NETLINK_MMAP from db1xxx_defconfig
  mm/huge_memory.c: fixup grammar in comment
  lib/xz: Add fall-through comments to a switch statement
2017-11-15 10:14:11 -08:00
Linus Torvalds
e2c5923c34 Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block
Pull core block layer updates from Jens Axboe:
 "This is the main pull request for block storage for 4.15-rc1.

  Nothing out of the ordinary in here, and no API changes or anything
  like that. Just various new features for drivers, core changes, etc.
  In particular, this pull request contains:

   - A patch series from Bart, closing the whole on blk/scsi-mq queue
     quescing.

   - A series from Christoph, building towards hidden gendisks (for
     multipath) and ability to move bio chains around.

   - NVMe
        - Support for native multipath for NVMe (Christoph).
        - Userspace notifications for AENs (Keith).
        - Command side-effects support (Keith).
        - SGL support (Chaitanya Kulkarni)
        - FC fixes and improvements (James Smart)
        - Lots of fixes and tweaks (Various)

   - bcache
        - New maintainer (Michael Lyle)
        - Writeback control improvements (Michael)
        - Various fixes (Coly, Elena, Eric, Liang, et al)

   - lightnvm updates, mostly centered around the pblk interface
     (Javier, Hans, and Rakesh).

   - Removal of unused bio/bvec kmap atomic interfaces (me, Christoph)

   - Writeback series that fix the much discussed hundreds of millions
     of sync-all units. This goes all the way, as discussed previously
     (me).

   - Fix for missing wakeup on writeback timer adjustments (Yafang
     Shao).

   - Fix laptop mode on blk-mq (me).

   - {mq,name} tupple lookup for IO schedulers, allowing us to have
     alias names. This means you can use 'deadline' on both !mq and on
     mq (where it's called mq-deadline). (me).

   - blktrace race fix, oopsing on sg load (me).

   - blk-mq optimizations (me).

   - Obscure waitqueue race fix for kyber (Omar).

   - NBD fixes (Josef).

   - Disable writeback throttling by default on bfq, like we do on cfq
     (Luca Miccio).

   - Series from Ming that enable us to treat flush requests on blk-mq
     like any other request. This is a really nice cleanup.

   - Series from Ming that improves merging on blk-mq with schedulers,
     getting us closer to flipping the switch on scsi-mq again.

   - BFQ updates (Paolo).

   - blk-mq atomic flags memory ordering fixes (Peter Z).

   - Loop cgroup support (Shaohua).

   - Lots of minor fixes from lots of different folks, both for core and
     driver code"

* 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits)
  nvme: fix visibility of "uuid" ns attribute
  blk-mq: fixup some comment typos and lengths
  ide: ide-atapi: fix compile error with defining macro DEBUG
  blk-mq: improve tag waiting setup for non-shared tags
  brd: remove unused brd_mutex
  blk-mq: only run the hardware queue if IO is pending
  block: avoid null pointer dereference on null disk
  fs: guard_bio_eod() needs to consider partitions
  xtensa/simdisk: fix compile error
  nvme: expose subsys attribute to sysfs
  nvme: create 'slaves' and 'holders' entries for hidden controllers
  block: create 'slaves' and 'holders' entries for hidden gendisks
  nvme: also expose the namespace identification sysfs files for mpath nodes
  nvme: implement multipath access to nvme subsystems
  nvme: track shared namespaces
  nvme: introduce a nvme_ns_ids structure
  nvme: track subsystems
  block, nvme: Introduce blk_mq_req_flags_t
  block, scsi: Make SCSI quiesce and resume work reliably
  block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag
  ...
2017-11-14 15:32:19 -08:00
Linus Torvalds
d6ec9d9a4d Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Ingo Molnar:
 "Note that in this cycle most of the x86 topics interacted at a level
  that caused them to be merged into tip:x86/asm - but this should be a
  temporary phenomenon, hopefully we'll back to the usual patterns in
  the next merge window.

  The main changes in this cycle were:

  Hardware enablement:

   - Add support for the Intel UMIP (User Mode Instruction Prevention)
     CPU feature. This is a security feature that disables certain
     instructions such as SGDT, SLDT, SIDT, SMSW and STR. (Ricardo Neri)

     [ Note that this is disabled by default for now, there are some
       smaller enhancements in the pipeline that I'll follow up with in
       the next 1-2 days, which allows this to be enabled by default.]

   - Add support for the AMD SEV (Secure Encrypted Virtualization) CPU
     feature, on top of SME (Secure Memory Encryption) support that was
     added in v4.14. (Tom Lendacky, Brijesh Singh)

   - Enable new SSE/AVX/AVX512 CPU features: AVX512_VBMI2, GFNI, VAES,
     VPCLMULQDQ, AVX512_VNNI, AVX512_BITALG. (Gayatri Kammela)

  Other changes:

   - A big series of entry code simplifications and enhancements (Andy
     Lutomirski)

   - Make the ORC unwinder default on x86 and various objtool
     enhancements. (Josh Poimboeuf)

   - 5-level paging enhancements (Kirill A. Shutemov)

   - Micro-optimize the entry code a bit (Borislav Petkov)

   - Improve the handling of interdependent CPU features in the early
     FPU init code (Andi Kleen)

   - Build system enhancements (Changbin Du, Masahiro Yamada)

   - ... plus misc enhancements, fixes and cleanups"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (118 commits)
  x86/build: Make the boot image generation less verbose
  selftests/x86: Add tests for the STR and SLDT instructions
  selftests/x86: Add tests for User-Mode Instruction Prevention
  x86/traps: Fix up general protection faults caused by UMIP
  x86/umip: Enable User-Mode Instruction Prevention at runtime
  x86/umip: Force a page fault when unable to copy emulated result to user
  x86/umip: Add emulation code for UMIP instructions
  x86/cpufeature: Add User-Mode Instruction Prevention definitions
  x86/insn-eval: Add support to resolve 16-bit address encodings
  x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode
  x86/insn-eval: Add wrapper function for 32 and 64-bit addresses
  x86/insn-eval: Add support to resolve 32-bit address encodings
  x86/insn-eval: Compute linear address in several utility functions
  resource: Fix resource_size.cocci warnings
  X86/KVM: Clear encryption attribute when SEV is active
  X86/KVM: Decrypt shared per-cpu variables when SEV is active
  percpu: Introduce DEFINE_PER_CPU_DECRYPTED
  x86: Add support for changing memory encryption attribute in early boot
  x86/io: Unroll string I/O when SEV is active
  x86/boot: Add early boot support when running with SEV active
  ...
2017-11-13 14:13:48 -08:00
Ingo Molnar
d04fdafc06 Merge branch 'x86/mm' into x86/asm, to merge branches
Most of x86/mm is already in x86/asm, so merge the rest too.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-10 08:05:30 +01:00
Kirill A. Shutemov
629a359bdb mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y
Since commit:

  83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")

we allocate the mem_section array dynamically in sparse_memory_present_with_active_regions(),
but some architectures, like arm64, don't call the routine to initialize sparsemem.

Let's move the initialization into memory_present() it should cover all
architectures.

Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Will Deacon <will.deacon@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-mm@kvack.org
Fixes: 83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Link: http://lkml.kernel.org/r/20171107083337.89952-1-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07 11:16:08 +01:00
Ingo Molnar
b3d9a13681 Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts
Conflicts:
	arch/x86/kernel/cpu/Makefile

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07 10:53:06 +01:00
Ingo Molnar
8c5db92a70 Merge branch 'linus' into locking/core, to resolve conflicts
Conflicts:
	include/linux/compiler-clang.h
	include/linux/compiler-gcc.h
	include/linux/compiler-intel.h
	include/uapi/linux/stddef.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07 10:32:44 +01:00
Christoph Hellwig
ea435e1b93 block: add a poll_fn callback to struct request_queue
That we we can also poll non blk-mq queues.  Mostly needed for
the NVMe multipath code, but could also be useful elsewhere.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-11-03 10:31:48 -06:00
Huang Ying
2628bd6fc0 mm, swap: fix race between swap count continuation operations
One page may store a set of entries of the sis->swap_map
(swap_info_struct->swap_map) in multiple swap clusters.

If some of the entries has sis->swap_map[offset] > SWAP_MAP_MAX,
multiple pages will be used to store the set of entries of the
sis->swap_map.  And the pages are linked with page->lru.  This is called
swap count continuation.  To access the pages which store the set of
entries of the sis->swap_map simultaneously, previously, sis->lock is
used.  But to improve the scalability of __swap_duplicate(), swap
cluster lock may be used in swap_count_continued() now.  This may race
with add_swap_count_continuation() which operates on a nearby swap
cluster, in which the sis->swap_map entries are stored in the same page.

The race can cause wrong swap count in practice, thus cause unfreeable
swap entries or software lockup, etc.

To fix the race, a new spin lock called cont_lock is added to struct
swap_info_struct to protect the swap count continuation page list.  This
is a lock at the swap device level, so the scalability isn't very well.
But it is still much better than the original sis->lock, because it is
only acquired/released when swap count continuation is used.  Which is
considered rare in practice.  If it turns out that the scalability
becomes an issue for some workloads, we can split the lock into some
more fine grained locks.

Link: http://lkml.kernel.org/r/20171017081320.28133-1-ying.huang@intel.com
Fixes: 235b621767 ("mm/swap: add cluster lock")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>	[4.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-03 07:39:19 -07:00
Zi Yan
dd8a67f9a3 mm/huge_memory.c: deposit page table when copying a PMD migration entry
We need to deposit pre-allocated PTE page table when a PMD migration
entry is copied in copy_huge_pmd().  Otherwise, we will leak the
pre-allocated page and cause a NULL pointer dereference later in
zap_huge_pmd().

The missing counters during PMD migration entry copy process are added
as well.

The bug report is here: https://lkml.org/lkml/2017/10/29/214

Link: http://lkml.kernel.org/r/20171030144636.4836-1-zi.yan@sent.com
Fixes: 84c3fc4e9c ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: 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>
2017-11-03 07:39:19 -07:00
Andrea Arcangeli
1e39214713 userfaultfd: hugetlbfs: prevent UFFDIO_COPY to fill beyond the end of i_size
This oops:

  kernel BUG at fs/hugetlbfs/inode.c:484!
  RIP: remove_inode_hugepages+0x3d0/0x410
  Call Trace:
    hugetlbfs_setattr+0xd9/0x130
    notify_change+0x292/0x410
    do_truncate+0x65/0xa0
    do_sys_ftruncate.constprop.3+0x11a/0x180
    SyS_ftruncate+0xe/0x10
    tracesys+0xd9/0xde

was caused by the lack of i_size check in hugetlb_mcopy_atomic_pte.

mmap() can still succeed beyond the end of the i_size after vmtruncate
zapped vmas in those ranges, but the faults must not succeed, and that
includes UFFDIO_COPY.

We could differentiate the retval to userland to represent a SIGBUS like
a page fault would do (vs SIGSEGV), but it doesn't seem very useful and
we'd need to pick a random retval as there's no meaningful syscall
retval that would differentiate from SIGSEGV and SIGBUS, there's just
-EFAULT.

Link: http://lkml.kernel.org/r/20171016223914.2421-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@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>
2017-11-03 07:39:19 -07:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Ingo Molnar
e17bae3266 Linux 4.14-rc7
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Merge tag 'v4.14-rc7' into x86/mm, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-30 10:30:09 +01:00
Mark Rutland
6aa7de0591 locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 11:01:08 +02:00
Paul E. McKenney
b03a0fe0c5 locking/atomics, mm: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't currently harmful.

However, for some features it is necessary to instrument reads and
writes separately, which is not possible with ACCESS_ONCE(). This
distinction is critical to correct operation.

It's possible to transform the bulk of kernel code using the Coccinelle
script below. However, this doesn't handle comments, leaving references
to ACCESS_ONCE() instances which have been removed. As a preparatory
step, this patch converts the mm code and comments to use
{READ,WRITE}_ONCE() consistently.

----
virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Link: http://lkml.kernel.org/r/1508792849-3115-15-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 11:01:06 +02:00
Will Deacon
506458efaf locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 13:17:33 +02:00
Linus Torvalds
b5ac3beb5a Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:
 "A little more than usual this time around. Been travelling, so that is
  part of it.

  Anyways, here are the highlights:

   1) Deal with memcontrol races wrt. listener dismantle, from Eric
      Dumazet.

   2) Handle page allocation failures properly in nfp driver, from Jaku
      Kicinski.

   3) Fix memory leaks in macsec, from Sabrina Dubroca.

   4) Fix crashes in pppol2tp_session_ioctl(), from Guillaume Nault.

   5) Several fixes in bnxt_en driver, including preventing potential
      NVRAM parameter corruption from Michael Chan.

   6) Fix for KRACK attacks in wireless, from Johannes Berg.

   7) rtnetlink event generation fixes from Xin Long.

   8) Deadlock in mlxsw driver, from Ido Schimmel.

   9) Disallow arithmetic operations on context pointers in bpf, from
      Jakub Kicinski.

  10) Missing sock_owned_by_user() check in sctp_icmp_redirect(), from
      Xin Long.

  11) Only TCP is supported for sockmap, make that explicit with a
      check, from John Fastabend.

  12) Fix IP options state races in DCCP and TCP, from Eric Dumazet.

  13) Fix panic in packet_getsockopt(), also from Eric Dumazet.

  14) Add missing locked in hv_sock layer, from Dexuan Cui.

  15) Various aquantia bug fixes, including several statistics handling
      cures. From Igor Russkikh et al.

  16) Fix arithmetic overflow in devmap code, from John Fastabend.

  17) Fix busted socket memory accounting when we get a fault in the tcp
      zero copy paths. From Willem de Bruijn.

  18) Don't leave opt->tot_len uninitialized in ipv6, from Eric Dumazet"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (106 commits)
  stmmac: Don't access tx_q->dirty_tx before netif_tx_lock
  ipv6: flowlabel: do not leave opt->tot_len with garbage
  of_mdio: Fix broken PHY IRQ in case of probe deferral
  textsearch: fix typos in library helpers
  rxrpc: Don't release call mutex on error pointer
  net: stmmac: Prevent infinite loop in get_rx_timestamp_status()
  net: stmmac: Fix stmmac_get_rx_hwtstamp()
  net: stmmac: Add missing call to dev_kfree_skb()
  mlxsw: spectrum_router: Configure TIGCR on init
  mlxsw: reg: Add Tunneling IPinIP General Configuration Register
  net: ethtool: remove error check for legacy setting transceiver type
  soreuseport: fix initialization race
  net: bridge: fix returning of vlan range op errors
  sock: correct sk_wmem_queued accounting on efault in tcp zerocopy
  bpf: add test cases to bpf selftests to cover all access tests
  bpf: fix pattern matches for direct packet access
  bpf: fix off by one for range markings with L{T, E} patterns
  bpf: devmap fix arithmetic overflow in bitmap_size calculation
  net: aquantia: Bad udp rate on default interrupt coalescing
  net: aquantia: Enable coalescing management via ethtool interface
  ...
2017-10-21 22:44:48 -04:00
Kirill A. Shutemov
83e3c48729 mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y
Size of the mem_section[] array depends on the size of the physical address space.

In preparation for boot-time switching between paging modes on x86-64
we need to make the allocation of mem_section[] dynamic, because otherwise
we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB
for 4-level paging and 2MB for 5-level paging mode.

The patch allocates the array on the first call to sparse_memory_present_with_active_regions().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-20 13:07:09 +02:00
Ingo Molnar
967535223f Merge branch 'x86/urgent' into x86/mm, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-20 13:06:52 +02:00
Daniel Borkmann
0ea7eeec24 mm, percpu: add support for __GFP_NOWARN flag
Add an option for pcpu_alloc() to support __GFP_NOWARN flag.
Currently, we always throw a warning when size or alignment
is unsupported (and also dump stack on failed allocation
requests). The warning itself is harmless since we return
NULL anyway for any failed request, which callers are
required to handle anyway. However, it becomes harmful when
panic_on_warn is set.

The rationale for the WARN() in pcpu_alloc() is that it can
be tracked when larger than supported allocation requests are
made such that allocations limits can be tweaked if warranted.
This makes sense for in-kernel users, however, there are users
of pcpu allocator where allocation size is derived from user
space requests, e.g. when creating BPF maps. In these cases,
the requests should fail gracefully without throwing a splat.

The current work-around was to check allocation size against
the upper limit of PCPU_MIN_UNIT_SIZE from call-sites for
bailing out prior to a call to pcpu_alloc() in order to
avoid throwing the WARN(). This is bad in multiple ways since
PCPU_MIN_UNIT_SIZE is an implementation detail, and having
the checks on call-sites only complicates the code for no
good reason. Thus, lets fix it generically by supporting the
__GFP_NOWARN flag that users can then use with calling the
__alloc_percpu_gfp() helper instead.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-19 13:13:49 +01:00
Yafang Shao
515c24c13c mm/page-writeback.c: make changes of dirty_writeback_centisecs take effect immediately
This patch is the followup of the prvious patch:
[writeback: schedule periodic writeback with sysctl].

There's another issue to fix.
For example,
- When the tunable was set to one hour and is reset to one second, the
  new setting will not take effect for up to one hour.

Kicking the flusher threads immediately fixes it.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-14 09:14:35 -06:00
Huang Ying
61b639723b mm, swap: use page-cluster as max window of VMA based swap readahead
When the VMA based swap readahead was introduced, a new knob

  /sys/kernel/mm/swap/vma_ra_max_order

was added as the max window of VMA swap readahead.  This is to make it
possible to use different max window for VMA based readahead and
original physical readahead.  But Minchan Kim pointed out that this will
cause a regression because setting page-cluster sysctl to zero cannot
disable swap readahead with the change.

To fix the regression, the page-cluster sysctl is used as the max window
of both the VMA based swap readahead and original physical swap
readahead.  If more fine grained control is needed in the future, more
knobs can be added as the subordinate knobs of the page-cluster sysctl.

The vma_ra_max_order knob is deleted.  Because the knob was introduced
in v4.14-rc1, and this patch is targeting being merged before v4.14
releasing, there should be no existing users of this newly added ABI.

Link: http://lkml.kernel.org/r/20171011070847.16003-1-ying.huang@intel.com
Fixes: ec560175c0 ("mm, swap: VMA based swap readahead")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reported-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:33 -07:00
Will Deacon
a7b100953a mm: page_vma_mapped: ensure pmd is loaded with READ_ONCE outside of lock
Loading the pmd without holding the pmd_lock exposes us to races with
concurrent updaters of the page tables but, worse still, it also allows
the compiler to cache the pmd value in a register and reuse it later on,
even if we've performed a READ_ONCE in between and seen a more recent
value.

In the case of page_vma_mapped_walk, this leads to the following crash
when the pmd loaded for the initial pmd_trans_huge check is all zeroes
and a subsequent valid table entry is loaded by check_pmd.  We then
proceed into map_pte, but the compiler re-uses the zero entry inside
pte_offset_map, resulting in a junk pointer being installed in
pvmw->pte:

  PC is at check_pte+0x20/0x170
  LR is at page_vma_mapped_walk+0x2e0/0x540
  [...]
  Process doio (pid: 2463, stack limit = 0xffff00000f2e8000)
  Call trace:
    check_pte+0x20/0x170
    page_vma_mapped_walk+0x2e0/0x540
    page_mkclean_one+0xac/0x278
    rmap_walk_file+0xf0/0x238
    rmap_walk+0x64/0xa0
    page_mkclean+0x90/0xa8
    clear_page_dirty_for_io+0x84/0x2a8
    mpage_submit_page+0x34/0x98
    mpage_process_page_bufs+0x164/0x170
    mpage_prepare_extent_to_map+0x134/0x2b8
    ext4_writepages+0x484/0xe30
    do_writepages+0x44/0xe8
    __filemap_fdatawrite_range+0xbc/0x110
    file_write_and_wait_range+0x48/0xd8
    ext4_sync_file+0x80/0x4b8
    vfs_fsync_range+0x64/0xc0
    SyS_msync+0x194/0x1e8

This patch fixes the problem by ensuring that READ_ONCE is used before
the initial checks on the pmd, and this value is subsequently used when
checking whether or not the pmd is present.  pmd_check is removed and
the pmd_present check is inlined directly.

Link: http://lkml.kernel.org/r/1507222630-5839-1-git-send-email-will.deacon@arm.com
Fixes: f27176cfc3 ("mm: convert page_mkclean_one() to use page_vma_mapped_walk()")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:33 -07:00
Johannes Weiner
b8c8a338f7 Revert "vmalloc: back off when the current task is killed"
This reverts commits 5d17a73a2e ("vmalloc: back off when the current
task is killed") and 171012f561 ("mm: don't warn when vmalloc() fails
due to a fatal signal").

Commit 5d17a73a2e ("vmalloc: back off when the current task is
killed") made all vmalloc allocations from a signal-killed task fail.
We have seen crashes in the tty driver from this, where a killed task
exiting tries to switch back to N_TTY, fails n_tty_open because of the
vmalloc failing, and later crashes when dereferencing tty->disc_data.

Arguably, relying on a vmalloc() call to succeed in order to properly
exit a task is not the most robust way of doing things.  There will be a
follow-up patch to the tty code to fall back to the N_NULL ldisc.

But the justification to make that vmalloc() call fail like this isn't
convincing, either.  The patch mentions an OOM victim exhausting the
memory reserves and thus deadlocking the machine.  But the OOM killer is
only one, improbable source of fatal signals.  It doesn't make sense to
fail allocations preemptively with plenty of memory in most cases.

The patch doesn't mention real-life instances where vmalloc sites would
exhaust memory, which makes it sound more like a theoretical issue to
begin with.  But just in case, the OOM access to memory reserves has
been restricted on the allocator side in cd04ae1e2d ("mm, oom: do not
rely on TIF_MEMDIE for memory reserves access"), which should take care
of any theoretical concerns on that front.

Revert this patch, and the follow-up that suppresses the allocation
warnings when we fail the allocations due to a signal.

Link: http://lkml.kernel.org/r/20171004185906.GB2136@cmpxchg.org
Fixes:  171012f561 ("mm: don't warn when vmalloc() fails due to a fatal signal")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Boris Brezillon
ef4650144e mm/cma.c: take __GFP_NOWARN into account in cma_alloc()
cma_alloc() unconditionally prints an INFO message when the CMA
allocation fails.  Make this message conditional on the non-presence of
__GFP_NOWARN in gfp_mask.

This patch aims at removing INFO messages that are displayed when the
VC4 driver tries to allocate buffer objects.  From the driver
perspective an allocation failure is acceptable, and the driver can
possibly do something to make following allocation succeed (like
flushing the VC4 internal cache).

Link: http://lkml.kernel.org/r/20171004125447.15195-1-boris.brezillon@free-electrons.com
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Eric Anholt <eric@anholt.net>
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>
2017-10-13 16:18:32 -07:00
Zi Yan
af0db981f3 mm: remove unnecessary WARN_ONCE in page_vma_mapped_walk().
A non present pmd entry can appear after pmd_lock is taken in
page_vma_mapped_walk(), even if THP migration is not enabled.  The
WARN_ONCE is unnecessary.

Link: http://lkml.kernel.org/r/20171003142606.12324-1-zi.yan@sent.com
Fixes: 616b837153 ("mm: thp: enable thp migration in generic path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Tested-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Andrey Ryabinin
de55c8b251 mm/mempolicy: fix NUMA_INTERLEAVE_HIT counter
Commit 3a321d2a3d ("mm: change the call sites of numa statistics
items") separated NUMA counters from zone counters, but the
NUMA_INTERLEAVE_HIT call site wasn't updated to use the new interface.
So alloc_page_interleave() actually increments NR_ZONE_INACTIVE_FILE
instead of NUMA_INTERLEAVE_HIT.

Fix this by using __inc_numa_state() interface to increment
NUMA_INTERLEAVE_HIT.

Link: http://lkml.kernel.org/r/20171003191003.8573-1-aryabinin@virtuozzo.com
Fixes: 3a321d2a3d ("mm: change the call sites of numa statistics items")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Kemi Wang <kemi.wang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Yang Shi
c02c300932 mm/madvise.c: add description for MADV_WIPEONFORK and MADV_KEEPONFORK
mm/madvise.c has a brief description about all MADV_ flags.  Add a
description for the newly added MADV_WIPEONFORK and MADV_KEEPONFORK.

Although man page has the similar information, but it'd better to keep
the consistent with other flags.

Link: http://lkml.kernel.org/r/1506117328-88228-1-git-send-email-yang.s@alibaba-inc.com
Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Mark Hairgrove
e20d103b6c mm/migrate: fix indexing bug (off by one) and avoid out of bound access
Index was incremented before last use and thus the second array could
dereference to an invalid address (not mentioning the fact that it did
not properly clear the entry we intended to clear).

Link: http://lkml.kernel.org/r/1506973525-16491-1-git-send-email-jglisse@redhat.com
Fixes: 8315ada7f0 ("mm/migrate: allow migrate_vma() to alloc new page on empty entry")
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Michael DeGuzis
b14d595aa2 mm/huge_memory.c: fixup grammar in comment
This patch fixes up some grammar and spelling in the information block for
huge_memory.c.

Signed-off-by: Michael DeGuzis <mdeguzis@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2017-10-12 15:11:56 +02:00
Eric Dumazet
9f1c2674b3 net: memcontrol: defer call to mem_cgroup_sk_alloc()
Instead of calling mem_cgroup_sk_alloc() from BH context,
it is better to call it from inet_csk_accept() in process context.

Not only this removes code in mem_cgroup_sk_alloc(), but it also
fixes a bug since listener might have been dismantled and css_get()
might cause a use-after-free.

Fixes: e994b2f0fb ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-09 20:55:01 -07:00
Yafang Shao
94af584692 writeback: schedule periodic writeback with sysctl
After disable periodic writeback by writing 0 to
dirty_writeback_centisecs, the handler wb_workfn() will not be
entered again until the dirty background limit reaches or
sync syscall is executed or no enough free memory available or
vmscan is triggered.

So the periodic writeback can't be enabled by writing a non-zero
value to dirty_writeback_centisecs.
As it can be disabled by sysctl, it should be able to enable by
sysctl as well.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-09 08:27:40 -06:00
Jens Axboe
775d3a35dc backing-dev: kill unused pdflush_proc_obsolete()
After commit b35bd0d9f8, pdflush_proc_obsolete() is no longer
used. Kill the function and declaration.

Reported-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-06 08:15:15 -06:00
YASUAKI ISHIMATSU
d09b0137d2 mm/memory_hotplug: define find_{smallest|biggest}_section_pfn as unsigned long
find_{smallest|biggest}_section_pfn()s find the smallest/biggest section
and return the pfn of the section.  But the functions are defined as int.
So the functions always return 0x00000000 - 0xffffffff.  It means if
memory address is over 16TB, the functions does not work correctly.

To handle 64 bit value, the patch defines
find_{smallest|biggest}_section_pfn() as unsigned long.

Fixes: 815121d2b5 ("memory_hotplug: clear zone when removing the memory")
Link: http://lkml.kernel.org/r/d9d5593a-d0a4-c4be-ab08-493df59a85c6@gmail.com
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:26 -07:00
YASUAKI ISHIMATSU
1dd2bfc868 mm/memory_hotplug: change pfn_to_section_nr/section_nr_to_pfn macro to inline function
pfn_to_section_nr() and section_nr_to_pfn() are defined as macro.
pfn_to_section_nr() has no issue even if it is defined as macro.  But
section_nr_to_pfn() has overflow issue if sec is defined as int.

section_nr_to_pfn() just shifts sec by PFN_SECTION_SHIFT.  If sec is
defined as unsigned long, section_nr_to_pfn() returns pfn as 64 bit value.
But if sec is defined as int, section_nr_to_pfn() returns pfn as 32 bit
value.

__remove_section() calculates start_pfn using section_nr_to_pfn() and
scn_nr defined as int.  So if hot-removed memory address is over 16TB,
overflow issue occurs and section_nr_to_pfn() does not calculate correct
pfn.

To make callers use proper arg, the patch changes the macros to inline
functions.

Fixes: 815121d2b5 ("memory_hotplug: clear zone when removing the memory")
Link: http://lkml.kernel.org/r/e643a387-e573-6bbf-d418-c60c8ee3d15e@gmail.com
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Michal Hocko
9b6e63cbf8 mm, page_alloc: add scheduling point to memmap_init_zone
memmap_init_zone gets a pfn range to initialize and it can be really
large resulting in a soft lockup on non-preemptible kernels

  NMI watchdog: BUG: soft lockup - CPU#31 stuck for 23s! [kworker/u642:5:1720]
  [...]
  task: ffff88ecd7e902c0 ti: ffff88eca4e50000 task.ti: ffff88eca4e50000
  RIP: move_pfn_range_to_zone+0x185/0x1d0
  [...]
  Call Trace:
    devm_memremap_pages+0x2c7/0x430
    pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
    nvdimm_bus_probe+0x64/0x110 [libnvdimm]
    driver_probe_device+0x1f7/0x420
    bus_for_each_drv+0x52/0x80
    __device_attach+0xb0/0x130
    bus_probe_device+0x87/0xa0
    device_add+0x3fc/0x5f0
    nd_async_device_register+0xe/0x40 [libnvdimm]
    async_run_entry_fn+0x43/0x150
    process_one_work+0x14e/0x410
    worker_thread+0x116/0x490
    kthread+0xc7/0xe0
    ret_from_fork+0x3f/0x70

Fix this by adding a scheduling point once per page block.

Link: http://lkml.kernel.org/r/20170918121410.24466-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Michal Hocko
f64ac5e6e3 mm, memory_hotplug: add scheduling point to __add_pages
Patch series "mm, memory_hotplug: fix few soft lockups in memory
hotadd".

Johannes has noticed few soft lockups when adding a large nvdimm device.
All of them were caused by a long loop without any explicit cond_resched
which is a problem for !PREEMPT kernels.

The fix is quite straightforward.  Just make sure that cond_resched gets
called from time to time.

This patch (of 3):

__add_pages gets a pfn range to add and there is no upper bound for a
single call.  This is usually a memory block aligned size for the
regular memory hotplug - smaller sizes are usual for memory balloning
drivers, or the whole NUMA node for physical memory online.  There is no
explicit scheduling point in that code path though.

This can lead to long latencies while __add_pages is executed and we
have even seen a soft lockup report during nvdimm initialization with
!PREEMPT kernel

  NMI watchdog: BUG: soft lockup - CPU#11 stuck for 23s! [kworker/u641:3:832]
  [...]
  Workqueue: events_unbound async_run_entry_fn
  task: ffff881809270f40 ti: ffff881809274000 task.ti: ffff881809274000
  RIP: _raw_spin_unlock_irqrestore+0x11/0x20
  RSP: 0018:ffff881809277b10  EFLAGS: 00000286
  [...]
  Call Trace:
    sparse_add_one_section+0x13d/0x18e
    __add_pages+0x10a/0x1d0
    arch_add_memory+0x4a/0xc0
    devm_memremap_pages+0x29d/0x430
    pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
    nvdimm_bus_probe+0x64/0x110 [libnvdimm]
    driver_probe_device+0x1f7/0x420
    bus_for_each_drv+0x52/0x80
    __device_attach+0xb0/0x130
    bus_probe_device+0x87/0xa0
    device_add+0x3fc/0x5f0
    nd_async_device_register+0xe/0x40 [libnvdimm]
    async_run_entry_fn+0x43/0x150
    process_one_work+0x14e/0x410
    worker_thread+0x116/0x490
    kthread+0xc7/0xe0
    ret_from_fork+0x3f/0x70
  DWARF2 unwinder stuck at ret_from_fork+0x3f/0x70

Fix this by adding cond_resched once per each memory section in the
given pfn range.  Each section is constant amount of work which itself
is not too expensive but many of them will just add up.

Link: http://lkml.kernel.org/r/20170918121410.24466-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Johannes Weiner
f80c7dab95 mm: memcontrol: use vmalloc fallback for large kmem memcg arrays
For quick per-memcg indexing, slab caches and list_lru structures
maintain linear arrays of descriptors.  As the number of concurrent
memory cgroups in the system goes up, this requires large contiguous
allocations (8k cgroups = order-5, 16k cgroups = order-6 etc.) for every
existing slab cache and list_lru, which can easily fail on loaded
systems.  E.g.:

  mkdir: page allocation failure: order:5, mode:0x14040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
  CPU: 1 PID: 6399 Comm: mkdir Not tainted 4.13.0-mm1-00065-g720bbe532b7c-dirty #481
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
  Call Trace:
   ? __alloc_pages_direct_compact+0x4c/0x110
   __alloc_pages_nodemask+0xf50/0x1430
   alloc_pages_current+0x60/0xc0
   kmalloc_order_trace+0x29/0x1b0
   __kmalloc+0x1f4/0x320
   memcg_update_all_list_lrus+0xca/0x2e0
   mem_cgroup_css_alloc+0x612/0x670
   cgroup_apply_control_enable+0x19e/0x360
   cgroup_mkdir+0x322/0x490
   kernfs_iop_mkdir+0x55/0x80
   vfs_mkdir+0xd0/0x120
   SyS_mkdirat+0x6c/0xe0
   SyS_mkdir+0x14/0x20
   entry_SYSCALL_64_fastpath+0x18/0xad
  Mem-Info:
  active_anon:2965 inactive_anon:19 isolated_anon:0
   active_file:100270 inactive_file:98846 isolated_file:0
   unevictable:0 dirty:0 writeback:0 unstable:0
   slab_reclaimable:7328 slab_unreclaimable:16402
   mapped:771 shmem:52 pagetables:278 bounce:0
   free:13718 free_pcp:0 free_cma:0

This output is from an artificial reproducer, but we have repeatedly
observed order-7 failures in production in the Facebook fleet.  These
systems become useless as they cannot run more jobs, even though there
is plenty of memory to allocate 128 individual pages.

Use kvmalloc and kvzalloc to fall back to vmalloc space if these arrays
prove too large for allocating them physically contiguous.

Link: http://lkml.kernel.org/r/20170918184919.20644-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Reza Arbab
7d790d2da3 mm/device-public-memory: fix edge case in _vm_normal_page()
With device public pages at the end of my memory space, I'm getting
output from _vm_normal_page():

  BUG: Bad page map in process migrate_pages  pte:c0800001ffff0d06 pmd:f95d3000
  addr:00007fff89330000 vm_flags:00100073 anon_vma:c0000000fa899320 mapping:          (null) index:7fff8933
  file:          (null) fault:          (null) mmap:          (null) readpage:          (null)
  CPU: 0 PID: 13963 Comm: migrate_pages Tainted: P    B      OE 4.14.0-rc1-wip #155
  Call Trace:
     dump_stack+0xb0/0xf4 (unreliable)
     print_bad_pte+0x28c/0x340
     _vm_normal_page+0xc0/0x140
     zap_pte_range+0x664/0xc10
     unmap_page_range+0x318/0x670
     unmap_vmas+0x74/0xe0
     exit_mmap+0xe8/0x1f0
     mmput+0xac/0x1f0
     do_exit+0x348/0xcd0
     do_group_exit+0x5c/0xf0
     SyS_exit_group+0x1c/0x20
     system_call+0x58/0x6c

The pfn causing this is the very last one.  Correct the bounds check
accordingly.

Fixes: df6ad69838 ("mm/device-public-memory: device memory cache coherent with CPU")
Link: http://lkml.kernel.org/r/1506092178-20351-1-git-send-email-arbab@linux.vnet.ibm.com
Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Shaohua Li
9625456cc7 mm: fix data corruption caused by lazyfree page
MADV_FREE clears pte dirty bit and then marks the page lazyfree (clear
SwapBacked).  There is no lock to prevent the page is added to swap
cache between these two steps by page reclaim.  If page reclaim finds
such page, it will simply add the page to swap cache without pageout the
page to swap because the page is marked as clean.  Next time, page fault
will read data from the swap slot which doesn't have the original data,
so we have a data corruption.  To fix issue, we mark the page dirty and
pageout the page.

However, we shouldn't dirty all pages which is clean and in swap cache.
swapin page is swap cache and clean too.  So we only dirty page which is
added into swap cache in page reclaim, which shouldn't be swapin page.
As Minchan suggested, simply dirty the page in add_to_swap can do the
job.

Fixes: 802a3a92ad ("mm: reclaim MADV_FREE pages")
Link: http://lkml.kernel.org/r/08c84256b007bf3f63c91d94383bd9eb6fee2daa.1506446061.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Shaohua Li
24c92eb7dc mm: avoid marking swap cached page as lazyfree
MADV_FREE clears pte dirty bit and then marks the page lazyfree (clear
SwapBacked).  There is no lock to prevent the page is added to swap
cache between these two steps by page reclaim.  Page reclaim could add
the page to swap cache and unmap the page.  After page reclaim, the page
is added back to lru.  At that time, we probably start draining per-cpu
pagevec and mark the page lazyfree.  So the page could be in a state
with SwapBacked cleared and PG_swapcache set.  Next time there is a
refault in the virtual address, do_swap_page can find the page from swap
cache but the page has PageSwapCache false because SwapBacked isn't set,
so do_swap_page will bail out and do nothing.  The task will keep
running into fault handler.

Fixes: 802a3a92ad ("mm: reclaim MADV_FREE pages")
Link: http://lkml.kernel.org/r/6537ef3814398c0073630b03f176263bc81f0902.1506446061.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Tested-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Jeff Layton
f4e222c56c mm: have filemap_check_and_advance_wb_err clear AS_EIO/AS_ENOSPC
Eryu noticed that he could sometimes get a leftover error reported when
it shouldn't be on fsync with ext2 and non-journalled ext4.

The problem is that writeback_single_inode still uses filemap_fdatawait.
That picks up a previously set AS_EIO flag, which would ordinarily have
been cleared before.

Since we're mostly using this function as a replacement for
filemap_check_errors, have filemap_check_and_advance_wb_err clear AS_EIO
and AS_ENOSPC when reporting an error.  That should allow the new
function to better emulate the behavior of the old with respect to these
flags.

Link: http://lkml.kernel.org/r/20170922133331.28812-1-jlayton@kernel.org
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Christophe Leroy
a872eb2131 mm: fix RODATA_TEST failure "rodata_test: test data was not read only"
On powerpc, RODATA_TEST fails with message the following messages:

  Freeing unused kernel memory: 528K
  rodata_test: test data was not read only

This is because GCC allocates it to .data section:

  c0695034 g     O .data	00000004 rodata_test_data

Since commit 056b9d8a76 ("mm: remove rodata_test_data export, add
pr_fmt"), rodata_test_data is used only inside rodata_test.c By
declaring it static, it gets properly allocated into .rodata section
instead of .data:

  c04df710 l     O .rodata	00000004 rodata_test_data

Fixes: 056b9d8a76 ("mm: remove rodata_test_data export, add pr_fmt")
Link: http://lkml.kernel.org/r/20170921093729.1080368AC1@po15668-vm-win7.idsi0.si.c-s.fr
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Arnd Bergmann
57148a64e8 mm: meminit: mark init_reserved_page as __meminit
The function is called from __meminit context and calls other __meminit
functions but isn't it self mark as such today:

  WARNING: vmlinux.o(.text.unlikely+0x4516): Section mismatch in reference from the function init_reserved_page() to the function .meminit.text:early_pfn_to_nid()
  The function init_reserved_page() references the function __meminit early_pfn_to_nid().
  This is often because init_reserved_page lacks a __meminit annotation or the annotation of early_pfn_to_nid is wrong.

On most compilers, we don't notice this because the function gets
inlined all the time.  Adding __meminit here fixes the harmless warning
for the old versions and is generally the correct annotation.

Link: http://lkml.kernel.org/r/20170915193149.901180-1-arnd@arndb.de
Fixes: 7e18adb4f8 ("mm: meminit: initialise remaining struct pages in parallel with kswapd")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Vitaly Wool
3552935742 z3fold: fix stale list handling
Fix the situation when clear_bit() is called for page->private before
the page pointer is actually assigned.  While at it, remove work_busy()
check because it is costly and does not give 100% guarantee anyway.

Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Davidlohr Bueso
6818600ff0 mm,compaction: serialize waitqueue_active() checks (for real)
Andrea brought to my attention that the L->{L,S} guarantees are
completely bogus for this case.  I was looking at the diagram, from the
offending commit, when that _is_ the race, we had the load reordered
already.

What we need is at least S->L semantics, thus simply use
wq_has_sleeper() to serialize the call for good.

Link: http://lkml.kernel.org/r/20170914175313.GB811@linux-80c1.suse
Fixes: 46acef048a (mm,compaction: serialize waitqueue_active() checks)
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Andrea Parri <parri.andrea@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Jérôme Glisse
3f2eb0287e mm/memcg: avoid page count check for zone device
Fix for 4.14, zone device page always have an elevated refcount of one
and thus page count sanity check in uncharge_page() is inappropriate for
them.

[mhocko@suse.com: nano-optimize VM_BUG_ON in uncharge_page]
Link: http://lkml.kernel.org/r/20170914190011.5217-1-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Evgeny Baskakov <ebaskakov@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Michal Hocko
72f0184c8a mm, memcg: remove hotplug locking from try_charge
The following lockdep splat has been noticed during LTP testing

  ======================================================
  WARNING: possible circular locking dependency detected
  4.13.0-rc3-next-20170807 #12 Not tainted
  ------------------------------------------------------
  a.out/4771 is trying to acquire lock:
   (cpu_hotplug_lock.rw_sem){++++++}, at: [<ffffffff812b4668>] drain_all_stock.part.35+0x18/0x140

  but task is already holding lock:
   (&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&mm->mmap_sem){++++++}:
         lock_acquire+0xc9/0x230
         __might_fault+0x70/0xa0
         _copy_to_user+0x23/0x70
         filldir+0xa7/0x110
         xfs_dir2_sf_getdents.isra.10+0x20c/0x2c0 [xfs]
         xfs_readdir+0x1fa/0x2c0 [xfs]
         xfs_file_readdir+0x30/0x40 [xfs]
         iterate_dir+0x17a/0x1a0
         SyS_getdents+0xb0/0x160
         entry_SYSCALL_64_fastpath+0x1f/0xbe

  -> #2 (&type->i_mutex_dir_key#3){++++++}:
         lock_acquire+0xc9/0x230
         down_read+0x51/0xb0
         lookup_slow+0xde/0x210
         walk_component+0x160/0x250
         link_path_walk+0x1a6/0x610
         path_openat+0xe4/0xd50
         do_filp_open+0x91/0x100
         file_open_name+0xf5/0x130
         filp_open+0x33/0x50
         kernel_read_file_from_path+0x39/0x80
         _request_firmware+0x39f/0x880
         request_firmware_direct+0x37/0x50
         request_microcode_fw+0x64/0xe0
         reload_store+0xf7/0x180
         dev_attr_store+0x18/0x30
         sysfs_kf_write+0x44/0x60
         kernfs_fop_write+0x113/0x1a0
         __vfs_write+0x37/0x170
         vfs_write+0xc7/0x1c0
         SyS_write+0x58/0xc0
         do_syscall_64+0x6c/0x1f0
         return_from_SYSCALL_64+0x0/0x7a

  -> #1 (microcode_mutex){+.+.+.}:
         lock_acquire+0xc9/0x230
         __mutex_lock+0x88/0x960
         mutex_lock_nested+0x1b/0x20
         microcode_init+0xbb/0x208
         do_one_initcall+0x51/0x1a9
         kernel_init_freeable+0x208/0x2a7
         kernel_init+0xe/0x104
         ret_from_fork+0x2a/0x40

  -> #0 (cpu_hotplug_lock.rw_sem){++++++}:
         __lock_acquire+0x153c/0x1550
         lock_acquire+0xc9/0x230
         cpus_read_lock+0x4b/0x90
         drain_all_stock.part.35+0x18/0x140
         try_charge+0x3ab/0x6e0
         mem_cgroup_try_charge+0x7f/0x2c0
         shmem_getpage_gfp+0x25f/0x1050
         shmem_fault+0x96/0x200
         __do_fault+0x1e/0xa0
         __handle_mm_fault+0x9c3/0xe00
         handle_mm_fault+0x16e/0x380
         __do_page_fault+0x24a/0x530
         do_page_fault+0x30/0x80
         page_fault+0x28/0x30

  other info that might help us debug this:

  Chain exists of:
    cpu_hotplug_lock.rw_sem --> &type->i_mutex_dir_key#3 --> &mm->mmap_sem

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(&mm->mmap_sem);
                                 lock(&type->i_mutex_dir_key#3);
                                 lock(&mm->mmap_sem);
    lock(cpu_hotplug_lock.rw_sem);

   *** DEADLOCK ***

  2 locks held by a.out/4771:
   #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530
   #1:  (percpu_charge_mutex){+.+...}, at: [<ffffffff812b4c97>] try_charge+0x397/0x6e0

The problem is very similar to the one fixed by commit a459eeb7b8
("mm, page_alloc: do not depend on cpu hotplug locks inside the
allocator").  We are taking hotplug locks while we can be sitting on top
of basically arbitrary locks.  This just calls for problems.

We can get rid of {get,put}_online_cpus, fortunately.  We do not have to
be worried about races with memory hotplug because drain_local_stock,
which is called from both the WQ draining and the memory hotplug
contexts, is always operating on the local cpu stock with IRQs disabled.

The only thing to be careful about is that the target memcg doesn't
vanish while we are still in drain_all_stock so take a reference on it.

Link: http://lkml.kernel.org/r/20170913090023.28322-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Tested-by: Artem Savkov <asavkov@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Michal Hocko
4d4bbd8526 mm, oom_reaper: skip mm structs with mmu notifiers
Andrea has noticed that the oom_reaper doesn't invalidate the range via
mmu notifiers (mmu_notifier_invalidate_range_start/end) and that can
corrupt the memory of the kvm guest for example.

tlb_flush_mmu_tlbonly already invokes mmu notifiers but that is not
sufficient as per Andrea:

 "mmu_notifier_invalidate_range cannot be used in replacement of
  mmu_notifier_invalidate_range_start/end. For KVM
  mmu_notifier_invalidate_range is a noop and rightfully so. A MMU
  notifier implementation has to implement either ->invalidate_range
  method or the invalidate_range_start/end methods, not both. And if you
  implement invalidate_range_start/end like KVM is forced to do, calling
  mmu_notifier_invalidate_range in common code is a noop for KVM.

  For those MMU notifiers that can get away only implementing
  ->invalidate_range, the ->invalidate_range is implicitly called by
  mmu_notifier_invalidate_range_end(). And only those secondary MMUs
  that share the same pagetable with the primary MMU (like AMD iommuv2)
  can get away only implementing ->invalidate_range"

As the callback is allowed to sleep and the implementation is out of
hand of the MM it is safer to simply bail out if there is an mmu
notifier registered.  In order to not fail too early make the
mm_has_notifiers check under the oom_lock and have a little nap before
failing to give the current oom victim some more time to exit.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170913113427.2291-1-mhocko@kernel.org
Fixes: aac4536355 ("mm, oom: introduce oom reaper")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@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>
2017-10-03 17:54:24 -07:00
Vitaly Wool
d5567c9df1 z3fold: fix potential race in z3fold_reclaim_page
It is possible that on a (partially) unsuccessful page reclaim,
kref_put() called in z3fold_reclaim_page() does not yield page release,
but the page is released shortly afterwards by another thread.  Then
z3fold_reclaim_page() would try to list_add() that (released) page again
which is obviously a bug.

To avoid that, spin_lock() has to be taken earlier, before the
kref_put() call mentioned earlier.

Link: http://lkml.kernel.org/r/20170913162937.bfff21c7d12b12a5f47639fd@gmail.com
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00