linux.git/mm/memory-failure.c, branch v6.1

hugetlbfs: don't delete error page from pagecache

2022-11-08T23:57:22+00:00

This change is very similar to the change that was made for shmem [1], and
it solves the same problem but for HugeTLBFS instead.

Currently, when poison is found in a HugeTLB page, the page is removed
from the page cache.  That means that attempting to map or read that
hugepage in the future will result in a new hugepage being allocated
instead of notifying the user that the page was poisoned.  As [1] states,
this is effectively memory corruption.

The fix is to leave the page in the page cache.  If the user attempts to
use a poisoned HugeTLB page with a syscall, the syscall will fail with
EIO, the same error code that shmem uses.  For attempts to map the page,
the thread will get a BUS_MCEERR_AR SIGBUS.

[1]: commit a76054266661 ("mm: shmem: don't truncate page if memory failure happens")

Link: https://lkml.kernel.org/r/20221018200125.848471-1-jthoughton@google.com
Signed-off-by: James Houghton 
Reviewed-by: Mike Kravetz 
Reviewed-by: Naoya Horiguchi 
Tested-by: Naoya Horiguchi 
Reviewed-by: Yang Shi 
Cc: Axel Rasmussen 
Cc: James Houghton 
Cc: Miaohe Lin 
Cc: Muchun Song 
Cc: 
Signed-off-by: Andrew Morton

rmap: remove page_unlock_anon_vma_read()

2022-10-03T21:02:54+00:00

This was simply an alias for anon_vma_unlock_read() since 2011.

Link: https://lkml.kernel.org/r/20220902194653.1739778-56-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton

mm/swap: add swp_offset_pfn() to fetch PFN from swap entry

2022-09-27T02:46:05+00:00

We've got a bunch of special swap entries that stores PFN inside the swap
offset fields.  To fetch the PFN, normally the user just calls
swp_offset() assuming that'll be the PFN.

Add a helper swp_offset_pfn() to fetch the PFN instead, fetching only the
max possible length of a PFN on the host, meanwhile doing proper check
with MAX_PHYSMEM_BITS to make sure the swap offsets can actually store the
PFNs properly always using the BUILD_BUG_ON() in is_pfn_swap_entry().

One reason to do so is we never tried to sanitize whether swap offset can
really fit for storing PFN.  At the meantime, this patch also prepares us
with the future possibility to store more information inside the swp
offset field, so assuming "swp_offset(entry)" to be the PFN will not stand
any more very soon.

Replace many of the swp_offset() callers to use swp_offset_pfn() where
proper.  Note that many of the existing users are not candidates for the
replacement, e.g.:

  (1) When the swap entry is not a pfn swap entry at all, or,
  (2) when we wanna keep the whole swp_offset but only change the swp type.

For the latter, it can happen when fork() triggered on a write-migration
swap entry pte, we may want to only change the migration type from
write->read but keep the rest, so it's not "fetching PFN" but "changing
swap type only".  They're left aside so that when there're more
information within the swp offset they'll be carried over naturally in
those cases.

Since at it, dropping hwpoison_entry_to_pfn() because that's exactly what
the new swp_offset_pfn() is about.

Link: https://lkml.kernel.org/r/20220811161331.37055-4-peterx@redhat.com
Signed-off-by: Peter Xu 
Reviewed-by: "Huang, Ying" 
Cc: Alistair Popple 
Cc: Andi Kleen 
Cc: Andrea Arcangeli 
Cc: David Hildenbrand 
Cc: Hugh Dickins 
Cc: "Kirill A . Shutemov" 
Cc: Minchan Kim 
Cc: Nadav Amit 
Cc: Vlastimil Babka 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton

mm, hwpoison: cleanup some obsolete comments

2022-09-27T02:46:04+00:00

1.Remove meaningless comment in kill_proc(). That doesn't tell anything.
2.Fix the wrong function name get_hwpoison_unless_zero(). It should be
get_page_unless_zero().
3.The gate keeper for free hwpoison page has moved to check_new_page().
Update the corresponding comment.

Link: https://lkml.kernel.org/r/20220830123604.25763-7-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Acked-by: Naoya Horiguchi 
Signed-off-by: Andrew Morton

mm, hwpoison: check PageTable() explicitly in hwpoison_user_mappings()

2022-09-27T02:46:04+00:00

PageTable can't be handled by memory_failure(). Filter it out explicitly in
hwpoison_user_mappings(). This will also make code more consistent with the
relevant check in unpoison_memory().

Link: https://lkml.kernel.org/r/20220830123604.25763-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Acked-by: Naoya Horiguchi 
Signed-off-by: Andrew Morton

mm, hwpoison: avoid unneeded page_mapped_in_vma() overhead in collect_procs_anon()

2022-09-27T02:46:04+00:00

If vma->vm_mm != t->mm, there's no need to call page_mapped_in_vma() as
add_to_kill() won't be called in this case. Move up the mm check to avoid
possible unneeded calling to page_mapped_in_vma().

Link: https://lkml.kernel.org/r/20220830123604.25763-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Acked-by: Naoya Horiguchi 
Signed-off-by: Andrew Morton

mm, hwpoison: use num_poisoned_pages_sub() to decrease num_poisoned_pages

2022-09-27T02:46:04+00:00

Use num_poisoned_pages_sub() to combine multiple atomic ops into one. Also
num_poisoned_pages_dec() can be killed as there's no caller now.

Link: https://lkml.kernel.org/r/20220830123604.25763-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Acked-by: Naoya Horiguchi 
Signed-off-by: Andrew Morton

mm, hwpoison: use __PageMovable() to detect non-lru movable pages

2022-09-27T02:46:03+00:00

It's more recommended to use __PageMovable() to detect non-lru movable
pages. We can avoid bumping page refcnt via isolate_movable_page() for
the isolated lru pages. Also if pages become PageLRU just after they're
checked but before trying to isolate them, isolate_lru_page() will be
called to do the right work.

[linmiaohe@huawei.com: fixes per Naoya Horiguchi]
  Link: https://lkml.kernel.org/r/1f7ee86e-7d28-0d8c-e0de-b7a5a94519e8@huawei.com
Link: https://lkml.kernel.org/r/20220830123604.25763-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Naoya Horiguchi 
Signed-off-by: Andrew Morton

mm, hwpoison: use ClearPageHWPoison() in memory_failure()

2022-09-27T02:46:03+00:00

Patch series "A few cleanup patches for memory-failure".

his series contains a few cleanup patches to use __PageMovable() to detect
non-lru movable pages, use num_poisoned_pages_sub() to reduce multiple
atomic ops overheads and so on.  More details can be found in the
respective changelogs.


This patch (of 6):

Use ClearPageHWPoison() instead of TestClearPageHWPoison() to clear page
hwpoison flags to avoid unneeded full memory barrier overhead.

Link: https://lkml.kernel.org/r/20220830123604.25763-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220830123604.25763-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Acked-by: Naoya Horiguchi 
Signed-off-by: Andrew Morton

Merge branch 'mm-hotfixes-stable' into mm-stable

2022-09-26T20:13:15+00:00