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bf60fc2314
15647 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Hugh Dickins
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bf60fc2314 |
mm: page_vma_mapped_walk(): use goto instead of while (1)
commit 474466301dfd8b39a10c01db740645f3f7ae9a28 upstream. page_vma_mapped_walk() cleanup: add a label this_pte, matching next_pte, and use "goto this_pte", in place of the "while (1)" loop at the end. Link: https://lkml.kernel.org/r/a52b234a-851-3616-2525-f42736e8934@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
|
9f85dcaf15 |
mm: page_vma_mapped_walk(): add a level of indentation
commit b3807a91aca7d21c05d5790612e49969117a72b9 upstream. page_vma_mapped_walk() cleanup: add a level of indentation to much of the body, making no functional change in this commit, but reducing the later diff when this is all converted to a loop. [hughd@google.com: : page_vma_mapped_walk(): add a level of indentation fix] Link: https://lkml.kernel.org/r/7f817555-3ce1-c785-e438-87d8efdcaf26@google.com Link: https://lkml.kernel.org/r/efde211-f3e2-fe54-977-ef481419e7f3@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
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e56bdb3976 |
mm: page_vma_mapped_walk(): crossing page table boundary
commit 448282487483d6fa5b2eeeafaa0acc681e544a9c upstream. page_vma_mapped_walk() cleanup: adjust the test for crossing page table boundary - I believe pvmw->address is always page-aligned, but nothing else here assumed that; and remember to reset pvmw->pte to NULL after unmapping the page table, though I never saw any bug from that. Link: https://lkml.kernel.org/r/799b3f9c-2a9e-dfef-5d89-26e9f76fd97@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
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8dc191ed9c |
mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block
commit e2e1d4076c77b3671cf8ce702535ae7dee3acf89 upstream. page_vma_mapped_walk() cleanup: rearrange the !pmd_present() block to follow the same "return not_found, return not_found, return true" pattern as the block above it (note: returning not_found there is never premature, since existence or prior existence of huge pmd guarantees good alignment). Link: https://lkml.kernel.org/r/378c8650-1488-2edf-9647-32a53cf2e21@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
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7b55a4bcfc |
mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd
commit 3306d3119ceacc43ea8b141a73e21fea68eec30c upstream. page_vma_mapped_walk() cleanup: re-evaluate pmde after taking lock, then use it in subsequent tests, instead of repeatedly dereferencing pointer. Link: https://lkml.kernel.org/r/53fbc9d-891e-46b2-cb4b-468c3b19238e@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
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1cb0b9059f |
mm: page_vma_mapped_walk(): settle PageHuge on entry
commit 6d0fd5987657cb0c9756ce684e3a74c0f6351728 upstream. page_vma_mapped_walk() cleanup: get the hugetlbfs PageHuge case out of the way at the start, so no need to worry about it later. Link: https://lkml.kernel.org/r/e31a483c-6d73-a6bb-26c5-43c3b880a2@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
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65febb41b4 |
mm: page_vma_mapped_walk(): use page for pvmw->page
commit f003c03bd29e6f46fef1b9a8e8d636ac732286d5 upstream. Patch series "mm: page_vma_mapped_walk() cleanup and THP fixes". I've marked all of these for stable: many are merely cleanups, but I think they are much better before the main fix than after. This patch (of 11): page_vma_mapped_walk() cleanup: sometimes the local copy of pvwm->page was used, sometimes pvmw->page itself: use the local copy "page" throughout. Link: https://lkml.kernel.org/r/589b358c-febc-c88e-d4c2-7834b37fa7bf@google.com Link: https://lkml.kernel.org/r/88e67645-f467-c279-bf5e-af4b5c6b13eb@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Will Deacon <will@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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Yang Shi
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825c28052b |
mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split
[ Upstream commit 504e070dc08f757bccaed6d05c0f53ecbfac8a23 ] When debugging the bug reported by Wang Yugui [1], try_to_unmap() may fail, but the first VM_BUG_ON_PAGE() just checks page_mapcount() however it may miss the failure when head page is unmapped but other subpage is mapped. Then the second DEBUG_VM BUG() that check total mapcount would catch it. This may incur some confusion. As this is not a fatal issue, so consolidate the two DEBUG_VM checks into one VM_WARN_ON_ONCE_PAGE(). [1] https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/ Link: https://lkml.kernel.org/r/d0f0db68-98b8-ebfb-16dc-f29df24cf012@google.com Signed-off-by: Yang Shi <shy828301@gmail.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Jan Kara <jack@suse.cz> Cc: Jue Wang <juew@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Note on stable backport: fixed up variables in split_huge_page_to_list(). Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
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0010275ca2 |
mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page()
[ Upstream commit 22061a1ffabdb9c3385de159c5db7aac3a4df1cc ]
There is a race between THP unmapping and truncation, when truncate sees
pmd_none() and skips the entry, after munmap's zap_huge_pmd() cleared
it, but before its page_remove_rmap() gets to decrement
compound_mapcount: generating false "BUG: Bad page cache" reports that
the page is still mapped when deleted. This commit fixes that, but not
in the way I hoped.
The first attempt used try_to_unmap(page, TTU_SYNC|TTU_IGNORE_MLOCK)
instead of unmap_mapping_range() in truncate_cleanup_page(): it has
often been an annoyance that we usually call unmap_mapping_range() with
no pages locked, but there apply it to a single locked page.
try_to_unmap() looks more suitable for a single locked page.
However, try_to_unmap_one() contains a VM_BUG_ON_PAGE(!pvmw.pte,page):
it is used to insert THP migration entries, but not used to unmap THPs.
Copy zap_huge_pmd() and add THP handling now? Perhaps, but their TLB
needs are different, I'm too ignorant of the DAX cases, and couldn't
decide how far to go for anon+swap. Set that aside.
The second attempt took a different tack: make no change in truncate.c,
but modify zap_huge_pmd() to insert an invalidated huge pmd instead of
clearing it initially, then pmd_clear() between page_remove_rmap() and
unlocking at the end. Nice. But powerpc blows that approach out of the
water, with its serialize_against_pte_lookup(), and interesting pgtable
usage. It would need serious help to get working on powerpc (with a
minor optimization issue on s390 too). Set that aside.
Just add an "if (page_mapped(page)) synchronize_rcu();" or other such
delay, after unmapping in truncate_cleanup_page()? Perhaps, but though
that's likely to reduce or eliminate the number of incidents, it would
give less assurance of whether we had identified the problem correctly.
This successful iteration introduces "unmap_mapping_page(page)" instead
of try_to_unmap(), and goes the usual unmap_mapping_range_tree() route,
with an addition to details. Then zap_pmd_range() watches for this
case, and does spin_unlock(pmd_lock) if so - just like
page_vma_mapped_walk() now does in the PVMW_SYNC case. Not pretty, but
safe.
Note that unmap_mapping_page() is doing a VM_BUG_ON(!PageLocked) to
assert its interface; but currently that's only used to make sure that
page->mapping is stable, and zap_pmd_range() doesn't care if the page is
locked or not. Along these lines, in invalidate_inode_pages2_range()
move the initial unmap_mapping_range() out from under page lock, before
then calling unmap_mapping_page() under page lock if still mapped.
Link: https://lkml.kernel.org/r/a2a4a148-cdd8-942c-4ef8-51b77f643dbe@google.com
Fixes:
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Jue Wang
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38cda6b5ab |
mm/thp: fix page_address_in_vma() on file THP tails
commit 31657170deaf1d8d2f6a1955fbc6fa9d228be036 upstream.
Anon THP tails were already supported, but memory-failure may need to
use page_address_in_vma() on file THP tails, which its page->mapping
check did not permit: fix it.
hughd adds: no current usage is known to hit the issue, but this does
fix a subtle trap in a general helper: best fixed in stable sooner than
later.
Link: https://lkml.kernel.org/r/a0d9b53-bf5d-8bab-ac5-759dc61819c1@google.com
Fixes:
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Hugh Dickins
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37ffe9f4d7 |
mm/thp: fix vma_address() if virtual address below file offset
commit 494334e43c16d63b878536a26505397fce6ff3a2 upstream. Running certain tests with a DEBUG_VM kernel would crash within hours, on the total_mapcount BUG() in split_huge_page_to_list(), while trying to free up some memory by punching a hole in a shmem huge page: split's try_to_unmap() was unable to find all the mappings of the page (which, on a !DEBUG_VM kernel, would then keep the huge page pinned in memory). When that BUG() was changed to a WARN(), it would later crash on the VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma) in mm/internal.h:vma_address(), used by rmap_walk_file() for try_to_unmap(). vma_address() is usually correct, but there's a wraparound case when the vm_start address is unusually low, but vm_pgoff not so low: vma_address() chooses max(start, vma->vm_start), but that decides on the wrong address, because start has become almost ULONG_MAX. Rewrite vma_address() to be more careful about vm_pgoff; move the VM_BUG_ON_VMA() out of it, returning -EFAULT for errors, so that it can be safely used from page_mapped_in_vma() and page_address_in_vma() too. Add vma_address_end() to apply similar care to end address calculation, in page_vma_mapped_walk() and page_mkclean_one() and try_to_unmap_one(); though it raises a question of whether callers would do better to supply pvmw->end to page_vma_mapped_walk() - I chose not, for a smaller patch. An irritation is that their apparent generality breaks down on KSM pages, which cannot be located by the page->index that page_to_pgoff() uses: as commit |
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Hugh Dickins
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66be14a926 |
mm/thp: try_to_unmap() use TTU_SYNC for safe splitting
commit 732ed55823fc3ad998d43b86bf771887bcc5ec67 upstream.
Stressing huge tmpfs often crashed on unmap_page()'s VM_BUG_ON_PAGE
(!unmap_success): with dump_page() showing mapcount:1, but then its raw
struct page output showing _mapcount ffffffff i.e. mapcount 0.
And even if that particular VM_BUG_ON_PAGE(!unmap_success) is removed,
it is immediately followed by a VM_BUG_ON_PAGE(compound_mapcount(head)),
and further down an IS_ENABLED(CONFIG_DEBUG_VM) total_mapcount BUG():
all indicative of some mapcount difficulty in development here perhaps.
But the !CONFIG_DEBUG_VM path handles the failures correctly and
silently.
I believe the problem is that once a racing unmap has cleared pte or
pmd, try_to_unmap_one() may skip taking the page table lock, and emerge
from try_to_unmap() before the racing task has reached decrementing
mapcount.
Instead of abandoning the unsafe VM_BUG_ON_PAGE(), and the ones that
follow, use PVMW_SYNC in try_to_unmap_one() in this case: adding
TTU_SYNC to the options, and passing that from unmap_page().
When CONFIG_DEBUG_VM, or for non-debug too? Consensus is to do the same
for both: the slight overhead added should rarely matter, except perhaps
if splitting sparsely-populated multiply-mapped shmem. Once confident
that bugs are fixed, TTU_SYNC here can be removed, and the race
tolerated.
Link: https://lkml.kernel.org/r/c1e95853-8bcd-d8fd-55fa-e7f2488e78f@google.com
Fixes:
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Hugh Dickins
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6527d8ef68 |
mm/thp: make is_huge_zero_pmd() safe and quicker
commit 3b77e8c8cde581dadab9a0f1543a347e24315f11 upstream.
Most callers of is_huge_zero_pmd() supply a pmd already verified
present; but a few (notably zap_huge_pmd()) do not - it might be a pmd
migration entry, in which the pfn is encoded differently from a present
pmd: which might pass the is_huge_zero_pmd() test (though not on x86,
since L1TF forced us to protect against that); or perhaps even crash in
pmd_page() applied to a swap-like entry.
Make it safe by adding pmd_present() check into is_huge_zero_pmd()
itself; and make it quicker by saving huge_zero_pfn, so that
is_huge_zero_pmd() will not need to do that pmd_page() lookup each time.
__split_huge_pmd_locked() checked pmd_trans_huge() before: that worked,
but is unnecessary now that is_huge_zero_pmd() checks present.
Link: https://lkml.kernel.org/r/21ea9ca-a1f5-8b90-5e88-95fb1c49bbfa@google.com
Fixes:
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Hugh Dickins
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a8f4ea1d38 |
mm/thp: fix __split_huge_pmd_locked() on shmem migration entry
[ Upstream commit 99fa8a48203d62b3743d866fc48ef6abaee682be ]
Patch series "mm/thp: fix THP splitting unmap BUGs and related", v10.
Here is v2 batch of long-standing THP bug fixes that I had not got
around to sending before, but prompted now by Wang Yugui's report
https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/
Wang Yugui has tested a rollup of these fixes applied to 5.10.39, and
they have done no harm, but have *not* fixed that issue: something more
is needed and I have no idea of what.
This patch (of 7):
Stressing huge tmpfs page migration racing hole punch often crashed on
the VM_BUG_ON(!pmd_present) in pmdp_huge_clear_flush(), with DEBUG_VM=y
kernel; or shortly afterwards, on a bad dereference in
__split_huge_pmd_locked() when DEBUG_VM=n. They forgot to allow for pmd
migration entries in the non-anonymous case.
Full disclosure: those particular experiments were on a kernel with more
relaxed mmap_lock and i_mmap_rwsem locking, and were not repeated on the
vanilla kernel: it is conceivable that stricter locking happens to avoid
those cases, or makes them less likely; but __split_huge_pmd_locked()
already allowed for pmd migration entries when handling anonymous THPs,
so this commit brings the shmem and file THP handling into line.
And while there: use old_pmd rather than _pmd, as in the following
blocks; and make it clearer to the eye that the !vma_is_anonymous()
block is self-contained, making an early return after accounting for
unmapping.
Link: https://lkml.kernel.org/r/af88612-1473-2eaa-903-8d1a448b26@google.com
Link: https://lkml.kernel.org/r/dd221a99-efb3-cd1d-6256-7e646af29314@google.com
Fixes:
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Xu Yu
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32f954e961 |
mm, thp: use head page in __migration_entry_wait()
commit ffc90cbb2970ab88b66ea51dd580469eede57b67 upstream.
We notice that hung task happens in a corner but practical scenario when
CONFIG_PREEMPT_NONE is enabled, as follows.
Process 0 Process 1 Process 2..Inf
split_huge_page_to_list
unmap_page
split_huge_pmd_address
__migration_entry_wait(head)
__migration_entry_wait(tail)
remap_page (roll back)
remove_migration_ptes
rmap_walk_anon
cond_resched
Where __migration_entry_wait(tail) is occurred in kernel space, e.g.,
copy_to_user in fstat, which will immediately fault again without
rescheduling, and thus occupy the cpu fully.
When there are too many processes performing __migration_entry_wait on
tail page, remap_page will never be done after cond_resched.
This makes __migration_entry_wait operate on the compound head page,
thus waits for remap_page to complete, whether the THP is split
successfully or roll back.
Note that put_and_wait_on_page_locked helps to drop the page reference
acquired with get_page_unless_zero, as soon as the page is on the wait
queue, before actually waiting. So splitting the THP is only prevented
for a brief interval.
Link: https://lkml.kernel.org/r/b9836c1dd522e903891760af9f0c86a2cce987eb.1623144009.git.xuyu@linux.alibaba.com
Fixes:
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Miaohe Lin
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bfd90b56d7 |
mm/rmap: use page_not_mapped in try_to_unmap()
[ Upstream commit b7e188ec98b1644ff70a6d3624ea16aadc39f5e0 ] page_mapcount_is_zero() calculates accurately how many mappings a hugepage has in order to check against 0 only. This is a waste of cpu time. We can do this via page_not_mapped() to save some possible atomic_read cycles. Remove the function page_mapcount_is_zero() as it's not used anymore and move page_not_mapped() above try_to_unmap() to avoid identifier undeclared compilation error. Link: https://lkml.kernel.org/r/20210130084904.35307-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Miaohe Lin
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ff81af8259 |
mm/rmap: remove unneeded semicolon in page_not_mapped()
[ Upstream commit e0af87ff7afcde2660be44302836d2d5618185af ] Remove extra semicolon without any functional change intended. Link: https://lkml.kernel.org/r/20210127093425.39640-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Andrew Morton
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f71ca814c2 |
mm/slub.c: include swab.h
commit 1b3865d016815cbd69a1879ca1c8a8901fda1072 upstream.
Fixes build with CONFIG_SLAB_FREELIST_HARDENED=y.
Hopefully. But it's the right thing to do anwyay.
Fixes:
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Kees Cook
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f6ed235754 |
mm/slub: actually fix freelist pointer vs redzoning
commit e41a49fadbc80b60b48d3c095d9e2ee7ef7c9a8e upstream.
It turns out that SLUB redzoning ("slub_debug=Z") checks from
s->object_size rather than from s->inuse (which is normally bumped to
make room for the freelist pointer), so a cache created with an object
size less than 24 would have the freelist pointer written beyond
s->object_size, causing the redzone to be corrupted by the freelist
pointer. This was very visible with "slub_debug=ZF":
BUG test (Tainted: G B ): Right Redzone overwritten
-----------------------------------------------------------------------------
INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb
INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200
INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620
Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........
Object (____ptrval____): 00 00 00 00 00 f6 f4 a5 ........
Redzone (____ptrval____): 40 1d e8 1a aa @....
Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........
Adjust the offset to stay within s->object_size.
(Note that no caches of in this size range are known to exist in the
kernel currently.)
Link: https://lkml.kernel.org/r/20210608183955.280836-4-keescook@chromium.org
Link: https://lore.kernel.org/linux-mm/20200807160627.GA1420741@elver.google.com/
Link: https://lore.kernel.org/lkml/0f7dd7b2-7496-5e2d-9488-2ec9f8e90441@suse.cz/Fixes:
|
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Kees Cook
|
4314c8c63b |
mm/slub: fix redzoning for small allocations
commit 74c1d3e081533825f2611e46edea1fcdc0701985 upstream.
The redzone area for SLUB exists between s->object_size and s->inuse
(which is at least the word-aligned object_size). If a cache were
created with an object_size smaller than sizeof(void *), the in-object
stored freelist pointer would overwrite the redzone (e.g. with boot
param "slub_debug=ZF"):
BUG test (Tainted: G B ): Right Redzone overwritten
-----------------------------------------------------------------------------
INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb
INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200
INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620
Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........
Object (____ptrval____): f6 f4 a5 40 1d e8 ...@..
Redzone (____ptrval____): 1a aa ..
Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........
Store the freelist pointer out of line when object_size is smaller than
sizeof(void *) and redzoning is enabled.
Additionally remove the "smaller than sizeof(void *)" check under
CONFIG_DEBUG_VM in kmem_cache_sanity_check() as it is now redundant:
SLAB and SLOB both handle small sizes.
(Note that no caches within this size range are known to exist in the
kernel currently.)
Link: https://lkml.kernel.org/r/20210608183955.280836-3-keescook@chromium.org
Fixes:
|
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Kees Cook
|
4a36fda16b |
mm/slub: clarify verification reporting
commit 8669dbab2ae56085c128894b181c2aa50f97e368 upstream. Patch series "Actually fix freelist pointer vs redzoning", v4. This fixes redzoning vs the freelist pointer (both for middle-position and very small caches). Both are "theoretical" fixes, in that I see no evidence of such small-sized caches actually be used in the kernel, but that's no reason to let the bugs continue to exist, especially since people doing local development keep tripping over it. :) This patch (of 3): Instead of repeating "Redzone" and "Poison", clarify which sides of those zones got tripped. Additionally fix column alignment in the trailer. Before: BUG test (Tainted: G B ): Redzone overwritten ... Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): f6 f4 a5 40 1d e8 ...@.. Redzone (____ptrval____): 1a aa .. Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ After: BUG test (Tainted: G B ): Right Redzone overwritten ... Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): f6 f4 a5 40 1d e8 ...@.. Redzone (____ptrval____): 1a aa .. Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ The earlier commits that slowly resulted in the "Before" reporting were: |
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Peter Xu
|
12eb3c2c1a |
mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare
commit 099dd6878b9b12d6bbfa6bf29ce0c8ddd38f6901 upstream.
I found it by pure code review, that pte_same_as_swp() of unuse_vma()
didn't take uffd-wp bit into account when comparing ptes.
pte_same_as_swp() returning false negative could cause failure to
swapoff swap ptes that was wr-protected by userfaultfd.
Link: https://lkml.kernel.org/r/20210603180546.9083-1-peterx@redhat.com
Fixes:
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yangerkun
|
9e379da727 |
mm/memory-failure: make sure wait for page writeback in memory_failure
[ Upstream commit e8675d291ac007e1c636870db880f837a9ea112a ]
Our syzkaller trigger the "BUG_ON(!list_empty(&inode->i_wb_list))" in
clear_inode:
kernel BUG at fs/inode.c:519!
Internal error: Oops - BUG: 0 [#1] SMP
Modules linked in:
Process syz-executor.0 (pid: 249, stack limit = 0x00000000a12409d7)
CPU: 1 PID: 249 Comm: syz-executor.0 Not tainted 4.19.95
Hardware name: linux,dummy-virt (DT)
pstate: 80000005 (Nzcv daif -PAN -UAO)
pc : clear_inode+0x280/0x2a8
lr : clear_inode+0x280/0x2a8
Call trace:
clear_inode+0x280/0x2a8
ext4_clear_inode+0x38/0xe8
ext4_free_inode+0x130/0xc68
ext4_evict_inode+0xb20/0xcb8
evict+0x1a8/0x3c0
iput+0x344/0x460
do_unlinkat+0x260/0x410
__arm64_sys_unlinkat+0x6c/0xc0
el0_svc_common+0xdc/0x3b0
el0_svc_handler+0xf8/0x160
el0_svc+0x10/0x218
Kernel panic - not syncing: Fatal exception
A crash dump of this problem show that someone called __munlock_pagevec
to clear page LRU without lock_page: do_mmap -> mmap_region -> do_munmap
-> munlock_vma_pages_range -> __munlock_pagevec.
As a result memory_failure will call identify_page_state without
wait_on_page_writeback. And after truncate_error_page clear the mapping
of this page. end_page_writeback won't call sb_clear_inode_writeback to
clear inode->i_wb_list. That will trigger BUG_ON in clear_inode!
Fix it by checking PageWriteback too to help determine should we skip
wait_on_page_writeback.
Link: https://lkml.kernel.org/r/20210604084705.3729204-1-yangerkun@huawei.com
Fixes:
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Mina Almasry
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2eb4ec9c2c |
mm, hugetlb: fix simple resv_huge_pages underflow on UFFDIO_COPY
[ Upstream commit d84cf06e3dd8c5c5b547b5d8931015fc536678e5 ]
The userfaultfd hugetlb tests cause a resv_huge_pages underflow. This
happens when hugetlb_mcopy_atomic_pte() is called with !is_continue on
an index for which we already have a page in the cache. When this
happens, we allocate a second page, double consuming the reservation,
and then fail to insert the page into the cache and return -EEXIST.
To fix this, we first check if there is a page in the cache which
already consumed the reservation, and return -EEXIST immediately if so.
There is still a rare condition where we fail to copy the page contents
AND race with a call for hugetlb_no_page() for this index and again we
will underflow resv_huge_pages. That is fixed in a more complicated
patch not targeted for -stable.
Test:
Hacked the code locally such that resv_huge_pages underflows produce a
warning, then:
./tools/testing/selftests/vm/userfaultfd hugetlb_shared 10
2 /tmp/kokonut_test/huge/userfaultfd_test && echo test success
./tools/testing/selftests/vm/userfaultfd hugetlb 10
2 /tmp/kokonut_test/huge/userfaultfd_test && echo test success
Both tests succeed and produce no warnings. After the test runs number
of free/resv hugepages is correct.
[mike.kravetz@oracle.com: changelog fixes]
Link: https://lkml.kernel.org/r/20210528004649.85298-1-almasrymina@google.com
Fixes:
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Ding Hui
|
68dcd32b32 |
mm/page_alloc: fix counting of free pages after take off from buddy
commit bac9c6fa1f929213bbd0ac9cdf21e8e2f0916828 upstream. Recently we found that there is a lot MemFree left in /proc/meminfo after do a lot of pages soft offline, it's not quite correct. Before Oscar's rework of soft offline for free pages [1], if we soft offline free pages, these pages are left in buddy with HWPoison flag, and NR_FREE_PAGES is not updated immediately. So the difference between NR_FREE_PAGES and real number of available free pages is also even big at the beginning. However, with the workload running, when we catch HWPoison page in any alloc functions subsequently, we will remove it from buddy, meanwhile update the NR_FREE_PAGES and try again, so the NR_FREE_PAGES will get more and more closer to the real number of available free pages. (regardless of unpoison_memory()) Now, for offline free pages, after a successful call take_page_off_buddy(), the page is no longer belong to buddy allocator, and will not be used any more, but we missed accounting NR_FREE_PAGES in this situation, and there is no chance to be updated later. Do update in take_page_off_buddy() like rmqueue() does, but avoid double counting if some one already set_migratetype_isolate() on the page. [1]: commit |
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Gerald Schaefer
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5f2e1e818e |
mm/debug_vm_pgtable: fix alignment for pmd/pud_advanced_tests()
commit 04f7ce3f07ce39b1a3ca03a56b238a53acc52cfd upstream.
In pmd/pud_advanced_tests(), the vaddr is aligned up to the next pmd/pud
entry, and so it does not match the given pmdp/pudp and (aligned down)
pfn any more.
For s390, this results in memory corruption, because the IDTE
instruction used e.g. in xxx_get_and_clear() will take the vaddr for
some calculations, in combination with the given pmdp. It will then end
up with a wrong table origin, ending on ...ff8, and some of those
wrongly set low-order bits will also select a wrong pagetable level for
the index addition. IDTE could therefore invalidate (or 0x20) something
outside of the page tables, depending on the wrongly picked index, which
in turn depends on the random vaddr.
As result, we sometimes see "BUG task_struct (Not tainted): Padding
overwritten" on s390, where one 0x5a padding value got overwritten with
0x7a.
Fix this by aligning down, similar to how the pmd/pud_aligned pfns are
calculated.
Link: https://lkml.kernel.org/r/20210525130043.186290-2-gerald.schaefer@linux.ibm.com
Fixes:
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Peter Xu
|
014868616d |
mm/hugetlb: fix F_SEAL_FUTURE_WRITE
commit 22247efd822e6d263f3c8bd327f3f769aea9b1d9 upstream.
Patch series "mm/hugetlb: Fix issues on file sealing and fork", v2.
Hugh reported issue with F_SEAL_FUTURE_WRITE not applied correctly to
hugetlbfs, which I can easily verify using the memfd_test program, which
seems that the program is hardly run with hugetlbfs pages (as by default
shmem).
Meanwhile I found another probably even more severe issue on that hugetlb
fork won't wr-protect child cow pages, so child can potentially write to
parent private pages. Patch 2 addresses that.
After this series applied, "memfd_test hugetlbfs" should start to pass.
This patch (of 2):
F_SEAL_FUTURE_WRITE is missing for hugetlb starting from the first day.
There is a test program for that and it fails constantly.
$ ./memfd_test hugetlbfs
memfd-hugetlb: CREATE
memfd-hugetlb: BASIC
memfd-hugetlb: SEAL-WRITE
memfd-hugetlb: SEAL-FUTURE-WRITE
mmap() didn't fail as expected
Aborted (core dumped)
I think it's probably because no one is really running the hugetlbfs test.
Fix it by checking FUTURE_WRITE also in hugetlbfs_file_mmap() as what we
do in shmem_mmap(). Generalize a helper for that.
Link: https://lkml.kernel.org/r/20210503234356.9097-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20210503234356.9097-2-peterx@redhat.com
Fixes:
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Axel Rasmussen
|
140cfd9980 |
userfaultfd: release page in error path to avoid BUG_ON
commit 7ed9d238c7dbb1fdb63ad96a6184985151b0171c upstream.
Consider the following sequence of events:
1. Userspace issues a UFFD ioctl, which ends up calling into
shmem_mfill_atomic_pte(). We successfully account the blocks, we
shmem_alloc_page(), but then the copy_from_user() fails. We return
-ENOENT. We don't release the page we allocated.
2. Our caller detects this error code, tries the copy_from_user() after
dropping the mmap_lock, and retries, calling back into
shmem_mfill_atomic_pte().
3. Meanwhile, let's say another process filled up the tmpfs being used.
4. So shmem_mfill_atomic_pte() fails to account blocks this time, and
immediately returns - without releasing the page.
This triggers a BUG_ON in our caller, which asserts that the page
should always be consumed, unless -ENOENT is returned.
To fix this, detect if we have such a "dangling" page when accounting
fails, and if so, release it before returning.
Link: https://lkml.kernel.org/r/20210428230858.348400-1-axelrasmussen@google.com
Fixes:
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Pavel Tatashin
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673422b97e |
mm/gup: check for isolation errors
[ Upstream commit 6e7f34ebb8d25d71ce7f4580ba3cbfc10b895580 ]
It is still possible that we pin movable CMA pages if there are
isolation errors and cma_page_list stays empty when we check again.
Check for isolation errors, and return success only when there are no
isolation errors, and cma_page_list is empty after checking.
Because isolation errors are transient, we retry indefinitely.
Link: https://lkml.kernel.org/r/20210215161349.246722-5-pasha.tatashin@soleen.com
Fixes:
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Pavel Tatashin
|
096c9482ce |
mm/gup: return an error on migration failure
[ Upstream commit f0f4463837da17a89d965dcbe4e411629dbcf308 ] When migration failure occurs, we still pin pages, which means that we may pin CMA movable pages which should never be the case. Instead return an error without pinning pages when migration failure happens. No need to retry migrating, because migrate_pages() already retries 10 times. Link: https://lkml.kernel.org/r/20210215161349.246722-4-pasha.tatashin@soleen.com Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Tyler Hicks <tyhicks@linux.microsoft.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> Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Pavel Tatashin
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7df511ef37 |
mm/gup: check every subpage of a compound page during isolation
[ Upstream commit 83c02c23d0747a7bdcd71f99a538aacec94b146c ]
When pages are isolated in check_and_migrate_movable_pages() we skip
compound number of pages at a time. However, as Jason noted, it is not
necessary correct that pages[i] corresponds to the pages that we
skipped. This is because it is possible that the addresses in this
range had split_huge_pmd()/split_huge_pud(), and these functions do not
update the compound page metadata.
The problem can be reproduced if something like this occurs:
1. User faulted huge pages.
2. split_huge_pmd() was called for some reason
3. User has unmapped some sub-pages in the range
4. User tries to longterm pin the addresses.
The resulting pages[i] might end-up having pages which are not compound
size page aligned.
Link: https://lkml.kernel.org/r/20210215161349.246722-3-pasha.tatashin@soleen.com
Fixes:
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Miaohe Lin
|
87c4e386b6 |
ksm: fix potential missing rmap_item for stable_node
[ Upstream commit c89a384e2551c692a9fe60d093fd7080f50afc51 ]
When removing rmap_item from stable tree, STABLE_FLAG of rmap_item is
cleared with head reserved. So the following scenario might happen: For
ksm page with rmap_item1:
cmp_and_merge_page
stable_node->head = &migrate_nodes;
remove_rmap_item_from_tree, but head still equal to stable_node;
try_to_merge_with_ksm_page failed;
return;
For the same ksm page with rmap_item2, stable node migration succeed this
time. The stable_node->head does not equal to migrate_nodes now. For ksm
page with rmap_item1 again:
cmp_and_merge_page
stable_node->head != &migrate_nodes && rmap_item->head == stable_node
return;
We would miss the rmap_item for stable_node and might result in failed
rmap_walk_ksm(). Fix this by set rmap_item->head to NULL when rmap_item
is removed from stable tree.
Link: https://lkml.kernel.org/r/20210330140228.45635-5-linmiaohe@huawei.com
Fixes:
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Miaohe Lin
|
aa0d6d1d3e |
mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page()
[ Upstream commit 34f5e9b9d1990d286199084efa752530ee3d8297 ]
If the zone device page does not belong to un-addressable device memory,
the variable entry will be uninitialized and lead to indeterminate pte
entry ultimately. Fix this unexpected case and warn about it.
Link: https://lkml.kernel.org/r/20210325131524.48181-4-linmiaohe@huawei.com
Fixes:
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Miaohe Lin
|
9639a754cc |
mm/hugeltb: handle the error case in hugetlb_fix_reserve_counts()
[ Upstream commit da56388c4397878a65b74f7fe97760f5aa7d316b ]
A rare out of memory error would prevent removal of the reserve map region
for a page. hugetlb_fix_reserve_counts() handles this rare case to avoid
dangling with incorrect counts. Unfortunately, hugepage_subpool_get_pages
and hugetlb_acct_memory could possibly fail too. We should correctly
handle these cases.
Link: https://lkml.kernel.org/r/20210410072348.20437-5-linmiaohe@huawei.com
Fixes:
|
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Miaohe Lin
|
14d45fb5a3 |
khugepaged: fix wrong result value for trace_mm_collapse_huge_page_isolate()
[ Upstream commit 74e579bf231a337ab3786d59e64bc94f45ca7b3f ]
In writable and !referenced case, the result value should be
SCAN_LACK_REFERENCED_PAGE for trace_mm_collapse_huge_page_isolate()
instead of default 0 (SCAN_FAIL) here.
Link: https://lkml.kernel.org/r/20210306032947.35921-5-linmiaohe@huawei.com
Fixes:
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Jane Chu
|
949e7c5f49 |
mm/memory-failure: unnecessary amount of unmapping
[ Upstream commit 4d75136be8bf3ae01b0bc3e725b2cdc921e103bd ]
It appears that unmap_mapping_range() actually takes a 'size' as its third
argument rather than a location, the current calling fashion causes
unnecessary amount of unmapping to occur.
Link: https://lkml.kernel.org/r/20210420002821.2749748-1-jane.chu@oracle.com
Fixes:
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Wang Wensheng
|
62d96faa74 |
mm/sparse: add the missing sparse_buffer_fini() in error branch
[ Upstream commit 2284f47fe9fe2ed2ef619e5474e155cfeeebd569 ]
sparse_buffer_init() and sparse_buffer_fini() should appear in pair, or a
WARN issue would be through the next time sparse_buffer_init() runs.
Add the missing sparse_buffer_fini() in error branch.
Link: https://lkml.kernel.org/r/20210325113155.118574-1-wangwensheng4@huawei.com
Fixes:
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Muchun Song
|
31df8bc4d3 |
mm: memcontrol: slab: fix obtain a reference to a freeing memcg
[ Upstream commit 9f38f03ae8d5f57371b71aa6b4275765b65454fd ]
Patch series "Use obj_cgroup APIs to charge kmem pages", v5.
Since Roman's series "The new cgroup slab memory controller" applied.
All slab objects are charged with the new APIs of obj_cgroup. The new
APIs introduce a struct obj_cgroup to charge slab objects. It prevents
long-living objects from pinning the original memory cgroup in the
memory. But there are still some corner objects (e.g. allocations
larger than order-1 page on SLUB) which are not charged with the new
APIs. Those objects (include the pages which are allocated from buddy
allocator directly) are charged as kmem pages which still hold a
reference to the memory cgroup.
E.g. We know that the kernel stack is charged as kmem pages because the
size of the kernel stack can be greater than 2 pages (e.g. 16KB on
x86_64 or arm64). If we create a thread (suppose the thread stack is
charged to memory cgroup A) and then move it from memory cgroup A to
memory cgroup B. Because the kernel stack of the thread hold a
reference to the memory cgroup A. The thread can pin the memory cgroup
A in the memory even if we remove the cgroup A. If we want to see this
scenario by using the following script. We can see that the system has
added 500 dying cgroups (This is not a real world issue, just a script
to show that the large kmallocs are charged as kmem pages which can pin
the memory cgroup in the memory).
#!/bin/bash
cat /proc/cgroups | grep memory
cd /sys/fs/cgroup/memory
echo 1 > memory.move_charge_at_immigrate
for i in range{1..500}
do
mkdir kmem_test
echo $$ > kmem_test/cgroup.procs
sleep 3600 &
echo $$ > cgroup.procs
echo `cat kmem_test/cgroup.procs` > cgroup.procs
rmdir kmem_test
done
cat /proc/cgroups | grep memory
This patchset aims to make those kmem pages to drop the reference to
memory cgroup by using the APIs of obj_cgroup. Finally, we can see that
the number of the dying cgroups will not increase if we run the above test
script.
This patch (of 7):
The rcu_read_lock/unlock only can guarantee that the memcg will not be
freed, but it cannot guarantee the success of css_get (which is in the
refill_stock when cached memcg changed) to memcg.
rcu_read_lock()
memcg = obj_cgroup_memcg(old)
__memcg_kmem_uncharge(memcg)
refill_stock(memcg)
if (stock->cached != memcg)
// css_get can change the ref counter from 0 back to 1.
css_get(&memcg->css)
rcu_read_unlock()
This fix is very like the commit:
eefbfa7fd678 ("mm: memcg/slab: fix use after free in obj_cgroup_charge")
Fix this by holding a reference to the memcg which is passed to the
__memcg_kmem_uncharge() before calling __memcg_kmem_uncharge().
Link: https://lkml.kernel.org/r/20210319163821.20704-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210319163821.20704-2-songmuchun@bytedance.com
Fixes: 3de7d4f25a74 ("mm: memcg/slab: optimize objcg stock draining")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Nikolay Borisov
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2e95bc6cfe |
mm/sl?b.c: remove ctor argument from kmem_cache_flags
[ Upstream commit 3754000872188e3e4713d9d847fe3c615a47c220 ]
This argument hasn't been used since
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Christophe Leroy
|
76af8126a6 |
mm: ptdump: fix build failure
commit 458376913d86bed2fb781b4952eb6861675ef3be upstream.
READ_ONCE() cannot be used for reading PTEs. Use ptep_get() instead, to
avoid the following errors:
CC mm/ptdump.o
In file included from <command-line>:
mm/ptdump.c: In function 'ptdump_pte_entry':
include/linux/compiler_types.h:320:38: error: call to '__compiletime_assert_207' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE().
320 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:301:4: note: in definition of macro '__compiletime_assert'
301 | prefix ## suffix(); \
| ^~~~~~
include/linux/compiler_types.h:320:2: note: in expansion of macro '_compiletime_assert'
320 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:2: note: in expansion of macro 'compiletime_assert'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:49:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
49 | compiletime_assert_rwonce_type(x); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/ptdump.c:114:14: note: in expansion of macro 'READ_ONCE'
114 | pte_t val = READ_ONCE(*pte);
| ^~~~~~~~~
make[2]: *** [mm/ptdump.o] Error 1
See commit
|
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|
Roman Gushchin
|
efa869b68b |
percpu: make pcpu_nr_empty_pop_pages per chunk type
commit 0760fa3d8f7fceeea508b98899f1c826e10ffe78 upstream.
nr_empty_pop_pages is used to guarantee that there are some free
populated pages to satisfy atomic allocations. Accounted and
non-accounted allocations are using separate sets of chunks,
so both need to have a surplus of empty pages.
This commit makes pcpu_nr_empty_pop_pages and the corresponding logic
per chunk type.
[Dennis]
This issue came up as I was reviewing [1] and realized I missed this.
Simultaneously, it was reported btrfs was seeing failed atomic
allocations in fsstress tests [2] and [3].
[1] https://lore.kernel.org/linux-mm/20210324190626.564297-1-guro@fb.com/
[2] https://lore.kernel.org/linux-mm/20210401185158.3275.409509F4@e16-tech.com/
[3] https://lore.kernel.org/linux-mm/CAL3q7H5RNBjCi708GH7jnczAOe0BLnacT9C+OBgA-Dx9jhB6SQ@mail.gmail.com/
Fixes:
|
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|
Ilya Lipnitskiy
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ec3e06e06f |
mm: fix race by making init_zero_pfn() early_initcall
commit e720e7d0e983bf05de80b231bccc39f1487f0f16 upstream.
There are code paths that rely on zero_pfn to be fully initialized
before core_initcall. For example, wq_sysfs_init() is a core_initcall
function that eventually results in a call to kernel_execve, which
causes a page fault with a subsequent mmput. If zero_pfn is not
initialized by then it may not get cleaned up properly and result in an
error:
BUG: Bad rss-counter state mm:(ptrval) type:MM_ANONPAGES val:1
Here is an analysis of the race as seen on a MIPS device. On this
particular MT7621 device (Ubiquiti ER-X), zero_pfn is PFN 0 until
initialized, at which point it becomes PFN 5120:
1. wq_sysfs_init calls into kobject_uevent_env at core_initcall:
kobject_uevent_env+0x7e4/0x7ec
kset_register+0x68/0x88
bus_register+0xdc/0x34c
subsys_virtual_register+0x34/0x78
wq_sysfs_init+0x1c/0x4c
do_one_initcall+0x50/0x1a8
kernel_init_freeable+0x230/0x2c8
kernel_init+0x10/0x100
ret_from_kernel_thread+0x14/0x1c
2. kobject_uevent_env() calls call_usermodehelper_exec() which executes
kernel_execve asynchronously.
3. Memory allocations in kernel_execve cause a page fault, bumping the
MM reference counter:
add_mm_counter_fast+0xb4/0xc0
handle_mm_fault+0x6e4/0xea0
__get_user_pages.part.78+0x190/0x37c
__get_user_pages_remote+0x128/0x360
get_arg_page+0x34/0xa0
copy_string_kernel+0x194/0x2a4
kernel_execve+0x11c/0x298
call_usermodehelper_exec_async+0x114/0x194
4. In case zero_pfn has not been initialized yet, zap_pte_range does
not decrement the MM_ANONPAGES RSS counter and the BUG message is
triggered shortly afterwards when __mmdrop checks the ref counters:
__mmdrop+0x98/0x1d0
free_bprm+0x44/0x118
kernel_execve+0x160/0x1d8
call_usermodehelper_exec_async+0x114/0x194
ret_from_kernel_thread+0x14/0x1c
To avoid races such as described above, initialize init_zero_pfn at
early_initcall level. Depending on the architecture, ZERO_PAGE is
either constant or gets initialized even earlier, at paging_init, so
there is no issue with initializing zero_pfn earlier.
Link: https://lkml.kernel.org/r/CALCv0x2YqOXEAy2Q=hafjhHCtTHVodChv1qpM=niAXOpqEbt7w@mail.gmail.com
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: stable@vger.kernel.org
Tested-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Hugh Dickins
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002ea848d7 |
mm/memcg: fix 5.10 backport of splitting page memcg
The straight backport of 5.12's e1baddf8475b ("mm/memcg: set memcg when
splitting page") works fine in 5.11, but turned out to be wrong for 5.10:
because that relies on a separate flag, which must also be set for the
memcg to be recognized and uncharged and cleared when freeing. Fix that.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Sean Christopherson
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de2e6b4e32 |
mm/mmu_notifiers: ensure range_end() is paired with range_start()
[ Upstream commit c2655835fd8cabdfe7dab737253de3ffb88da126 ]
If one or more notifiers fails .invalidate_range_start(), invoke
.invalidate_range_end() for "all" notifiers. If there are multiple
notifiers, those that did not fail are expecting _start() and _end() to
be paired, e.g. KVM's mmu_notifier_count would become imbalanced.
Disallow notifiers that can fail _start() from implementing _end() so
that it's unnecessary to either track which notifiers rejected _start(),
or had already succeeded prior to a failed _start().
Note, the existing behavior of calling _start() on all notifiers even
after a previous notifier failed _start() was an unintented "feature".
Make it canon now that the behavior is depended on for correctness.
As of today, the bug is likely benign:
1. The only caller of the non-blocking notifier is OOM kill.
2. The only notifiers that can fail _start() are the i915 and Nouveau
drivers.
3. The only notifiers that utilize _end() are the SGI UV GRU driver
and KVM.
4. The GRU driver will never coincide with the i195/Nouveau drivers.
5. An imbalanced kvm->mmu_notifier_count only causes soft lockup in the
_guest_, and the guest is already doomed due to being an OOM victim.
Fix the bug now to play nice with future usage, e.g. KVM has a
potential use case for blocking memslot updates in KVM while an
invalidation is in-progress, and failure to unblock would result in said
updates being blocked indefinitely and hanging.
Found by inspection. Verified by adding a second notifier in KVM that
periodically returns -EAGAIN on non-blockable ranges, triggering OOM,
and observing that KVM exits with an elevated notifier count.
Link: https://lkml.kernel.org/r/20210311180057.1582638-1-seanjc@google.com
Fixes:
|
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Miaohe Lin
|
fe03ccc3ce |
hugetlb_cgroup: fix imbalanced css_get and css_put pair for shared mappings
commit d85aecf2844ff02a0e5f077252b2461d4f10c9f0 upstream.
The current implementation of hugetlb_cgroup for shared mappings could
have different behavior. Consider the following two scenarios:
1.Assume initial css reference count of hugetlb_cgroup is 1:
1.1 Call hugetlb_reserve_pages with from = 1, to = 2. So css reference
count is 2 associated with 1 file_region.
1.2 Call hugetlb_reserve_pages with from = 2, to = 3. So css reference
count is 3 associated with 2 file_region.
1.3 coalesce_file_region will coalesce these two file_regions into
one. So css reference count is 3 associated with 1 file_region
now.
2.Assume initial css reference count of hugetlb_cgroup is 1 again:
2.1 Call hugetlb_reserve_pages with from = 1, to = 3. So css reference
count is 2 associated with 1 file_region.
Therefore, we might have one file_region while holding one or more css
reference counts. This inconsistency could lead to imbalanced css_get()
and css_put() pair. If we do css_put one by one (i.g. hole punch case),
scenario 2 would put one more css reference. If we do css_put all
together (i.g. truncate case), scenario 1 will leak one css reference.
The imbalanced css_get() and css_put() pair would result in a non-zero
reference when we try to destroy the hugetlb cgroup. The hugetlb cgroup
directory is removed __but__ associated resource is not freed. This
might result in OOM or can not create a new hugetlb cgroup in a busy
workload ultimately.
In order to fix this, we have to make sure that one file_region must
hold exactly one css reference. So in coalesce_file_region case, we
should release one css reference before coalescence. Also only put css
reference when the entire file_region is removed.
The last thing to note is that the caller of region_add() will only hold
one reference to h_cg->css for the whole contiguous reservation region.
But this area might be scattered when there are already some
file_regions reside in it. As a result, many file_regions may share only
one h_cg->css reference. In order to ensure that one file_region must
hold exactly one css reference, we should do css_get() for each
file_region and release the reference held by caller when they are done.
[linmiaohe@huawei.com: fix imbalanced css_get and css_put pair for shared mappings]
Link: https://lkml.kernel.org/r/20210316023002.53921-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210301120540.37076-1-linmiaohe@huawei.com
Fixes:
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Thomas Hebb
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1d215fcbc4 |
z3fold: prevent reclaim/free race for headless pages
commit 6d679578fe9c762c8fbc3d796a067cbba84a7884 upstream.
Commit
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Zhou Guanghui
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efb12c03fc |
mm/memcg: set memcg when splitting page
commit e1baddf8475b06cc56f4bafecf9a32a124343d9f upstream.
As described in the split_page() comment, for the non-compound high order
page, the sub-pages must be freed individually. If the memcg of the first
page is valid, the tail pages cannot be uncharged when be freed.
For example, when alloc_pages_exact is used to allocate 1MB continuous
physical memory, 2MB is charged(kmemcg is enabled and __GFP_ACCOUNT is
set). When make_alloc_exact free the unused 1MB and free_pages_exact free
the applied 1MB, actually, only 4KB(one page) is uncharged.
Therefore, the memcg of the tail page needs to be set when splitting a
page.
Michel:
There are at least two explicit users of __GFP_ACCOUNT with
alloc_exact_pages added recently. See
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Zhou Guanghui
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6143a1d193 |
mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument
commit be6c8982e4ab9a41907555f601b711a7e2a17d4c upstream. Rename mem_cgroup_split_huge_fixup to split_page_memcg and explicitly pass in page number argument. In this way, the interface name is more common and can be used by potential users. In addition, the complete info(memcg and flag) of the memcg needs to be set to the tail pages. Link: https://lkml.kernel.org/r/20210304074053.65527-2-zhouguanghui1@huawei.com Signed-off-by: Zhou Guanghui <zhouguanghui1@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Tianhong Ding <dingtianhong@huawei.com> Cc: Weilong Chen <chenweilong@huawei.com> Cc: Rui Xiang <rui.xiang@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Mike Rapoport
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4c84191cbc |
mm/page_alloc.c: refactor initialization of struct page for holes in memory layout
commit 0740a50b9baa4472cfb12442df4b39e2712a64a4 upstream. There could be struct pages that are not backed by actual physical memory. This can happen when the actual memory bank is not a multiple of SECTION_SIZE or when an architecture does not register memory holes reserved by the firmware as memblock.memory. Such pages are currently initialized using init_unavailable_mem() function that iterates through PFNs in holes in memblock.memory and if there is a struct page corresponding to a PFN, the fields of this page are set to default values and it is marked as Reserved. init_unavailable_mem() does not take into account zone and node the page belongs to and sets both zone and node links in struct page to zero. Before commit |
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Suren Baghdasaryan
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518f98e390 |
mm/madvise: replace ptrace attach requirement for process_madvise
commit 96cfe2c0fd23ea7c2368d14f769d287e7ae1082e upstream. process_madvise currently requires ptrace attach capability. PTRACE_MODE_ATTACH gives one process complete control over another process. It effectively removes the security boundary between the two processes (in one direction). Granting ptrace attach capability even to a system process is considered dangerous since it creates an attack surface. This severely limits the usage of this API. The operations process_madvise can perform do not affect the correctness of the operation of the target process; they only affect where the data is physically located (and therefore, how fast it can be accessed). What we want is the ability for one process to influence another process in order to optimize performance across the entire system while leaving the security boundary intact. Replace PTRACE_MODE_ATTACH with a combination of PTRACE_MODE_READ and CAP_SYS_NICE. PTRACE_MODE_READ to prevent leaking ASLR metadata and CAP_SYS_NICE for influencing process performance. Link: https://lkml.kernel.org/r/20210303185807.2160264-1-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Jann Horn <jannh@google.com> Cc: Jeff Vander Stoep <jeffv@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tim Murray <timmurray@google.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: <stable@vger.kernel.org> [5.10+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |