linux-toradex.git/mm, branch v5.12

mm/filemap: fix mapping_seek_hole_data on THP & 32-bit

2021-04-23T21:42:39+00:00

No problem on 64-bit, or without huge pages, but xfstests generic/285
and other SEEK_HOLE/SEEK_DATA tests have regressed on huge tmpfs, and on
32-bit architectures, with the new mapping_seek_hole_data().  Several
different bugs turned out to need fixing.

u64 cast to stop losing bits when converting unsigned long to loff_t
(and let's use shifts throughout, rather than mixed with * and /).

Use round_up() when advancing pos, to stop assuming that pos was already
THP-aligned when advancing it by THP-size.  (This use of round_up()
assumes that any THP has THP-aligned index: true at present and true
going forward, but could be recoded to avoid the assumption.)

Use xas_set() when iterating away from a THP, so that xa_index stays in
synch with start, instead of drifting away to return bogus offset.

Check start against end to avoid wrapping 32-bit xa_index to 0 (and to
handle these additional cases, seek_data or not, it's easier to break
the loop than goto: so rearrange exit from the function).

[hughd@google.com: remove unneeded u64 casts, per Matthew]
  Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104221347240.1170@eggly.anvils

Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104211737410.3299@eggly.anvils
Fixes: 41139aa4c3a3 ("mm/filemap: add mapping_seek_hole_data")
Signed-off-by: Hugh Dickins 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Jan Kara 
Cc: Johannes Weiner 
Cc: "Kirill A. Shutemov" 
Cc: Matthew Wilcox 
Cc: William Kucharski 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/filemap: fix find_lock_entries hang on 32-bit THP

2021-04-23T21:42:39+00:00

No problem on 64-bit, or without huge pages, but xfstests generic/308
hung uninterruptibly on 32-bit huge tmpfs.

Since commit 0cc3b0ec23ce ("Clarify (and fix) in 4.13 MAX_LFS_FILESIZE
macros"), MAX_LFS_FILESIZE is only a PAGE_SIZE away from wrapping 32-bit
xa_index to 0, so the new find_lock_entries() has to be extra careful
when handling a THP.

Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104211735430.3299@eggly.anvils
Fixes: 5c211ba29deb ("mm: add and use find_lock_entries")
Signed-off-by: Hugh Dickins 
Cc: Matthew Wilcox 
Cc: William Kucharski 
Cc: Christoph Hellwig 
Cc: Jan Kara 
Cc: Dave Chinner 
Cc: Johannes Weiner 
Cc: "Kirill A. Shutemov" 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: ptdump: fix build failure

2021-04-16T23:10:37+00:00

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 :
  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 481e980a7c19 ("mm: Allow arches to provide ptep_get()") and
commit c0e1c8c22beb ("powerpc/8xx: Provide ptep_get() with 16k pages")
for details.

Link: https://lkml.kernel.org/r/912b349e2bcaa88939904815ca0af945740c6bd4.1618478922.git.christophe.leroy@csgroup.eu
Fixes: 30d621f6723b ("mm: add generic ptdump")
Signed-off-by: Christophe Leroy 
Cc: Steven Price 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/mapping_dirty_helpers: guard hugepage pud's usage

2021-04-16T23:10:37+00:00

Mapping dirty helpers have, so far, been only used on X86, but a port of
vmwgfx to ARM64 exposed a problem which results in a compilation error
on ARM64 systems:

  mm/mapping_dirty_helpers.c: In function `wp_clean_pud_entry':
  mm/mapping_dirty_helpers.c:172:32: error: implicit declaration of function `pud_dirty'; did you mean `pmd_dirty'? [-Werror=implicit-function-declaration]

This is due to the fact that mapping_dirty_helpers code assumes that
pud_dirty is always defined, which is not the case for architectures
that don't define CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD.

ARM64 arch is a little inconsistent when it comes to PUD hugepage
helpers, e.g. it defines pud_young but not pud_dirty but regardless of
that the core kernel code shouldn't assume that any of the PUD hugepage
helpers are available unless CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
is defined.  This prevents compilation errors whenever one of the
drivers is ported to new architectures.

Link: https://lkml.kernel.org/r/20210409165151.694574-1-zackr@vmware.com
Signed-off-by: Zack Rusin 
Reviewed-by: Thomas Hellstrm (Intel) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan: remove redundant config option

2021-04-16T23:10:36+00:00

CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN stack
instrumentation, but we should only need one config, so that we remove
CONFIG_KASAN_STACK_ENABLE and make CONFIG_KASAN_STACK workable.  see [1].

When enable KASAN stack instrumentation, then for gcc we could do no
prompt and default value y, and for clang prompt and default value n.

This patch fixes the following compilation warning:

  include/linux/kasan.h:333:30: warning: 'CONFIG_KASAN_STACK' is not defined, evaluates to 0 [-Wundef]

[akpm@linux-foundation.org: fix merge snafu]

Link: https://bugzilla.kernel.org/show_bug.cgi?id=210221 [1]
Link: https://lkml.kernel.org/r/20210226012531.29231-1-walter-zh.wu@mediatek.com
Fixes: d9b571c885a8 ("kasan: fix KASAN_STACK dependency for HW_TAGS")
Signed-off-by: Walter Wu 
Suggested-by: Dmitry Vyukov 
Reviewed-by: Nathan Chancellor 
Acked-by: Arnd Bergmann 
Reviewed-by: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Alexander Potapenko 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: eliminate "expecting prototype" kernel-doc warnings

2021-04-16T23:10:36+00:00

Fix stray kernel-doc warnings in mm/ due to mis-typed or missing function
names.

Quietens these kernel-doc warnings:

  mm/mmu_gather.c:264: warning: expecting prototype for tlb_gather_mmu(). Prototype was for __tlb_gather_mmu() instead
  mm/oom_kill.c:180: warning: expecting prototype for Check whether unreclaimable slab amount is greater than(). Prototype was for should_dump_unreclaim_slab() instead
  mm/shuffle.c:155: warning: expecting prototype for shuffle_free_memory(). Prototype was for __shuffle_free_memory() instead

Link: https://lkml.kernel.org/r/20210411210642.11362-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap 
Reviewed-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-5.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu

2021-04-10T19:51:12+00:00

Pull percpu fix from Dennis Zhou:
 "This contains a fix for sporadically failing atomic percpu
  allocations.

  I only caught it recently while I was reviewing a new series [1] and
  simultaneously saw reports by btrfs in xfstests [2] and [3].

  In v5.9, memcg accounting was extended to percpu done by adding a
  second type of chunk. I missed an interaction with the free page float
  count used to ensure we can support atomic allocations. If one type of
  chunk has no free pages, but the other has enough to satisfy the free
  page float requirement, we will not repopulate the free pages for the
  former type of chunk. This led to the sporadically failing atomic
  allocations"

Link: https://lore.kernel.org/linux-mm/20210324190626.564297-1-guro@fb.com/ [1]
Link: https://lore.kernel.org/linux-mm/20210401185158.3275.409509F4@e16-tech.com/ [2]
Link: https://lore.kernel.org/linux-mm/CAL3q7H5RNBjCi708GH7jnczAOe0BLnacT9C+OBgA-Dx9jhB6SQ@mail.gmail.com/ [3]

* 'for-5.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
  percpu: make pcpu_nr_empty_pop_pages per chunk type

kasan: fix conflict with page poisoning

2021-04-09T21:54:23+00:00

When page poisoning is enabled, it accesses memory that is marked as
poisoned by KASAN, which leas to false-positive KASAN reports.

Suppress the reports by adding KASAN annotations to unpoison_page()
(poison_page() already has them).

Link: https://lkml.kernel.org/r/2dc799014d31ac13fd97bd906bad33e16376fc67.1617118501.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Cc: Alexander Potapenko 
Cc: Marco Elver 
Cc: Dmitry Vyukov 
Cc: Andrey Ryabinin 
Cc: Andrey Konovalov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/gup: check page posion status for coredump.

2021-04-09T21:54:23+00:00

When we do coredump for user process signal, this may be an SIGBUS signal
with BUS_MCEERR_AR or BUS_MCEERR_AO code, which means this signal is
resulted from ECC memory fail like SRAR or SRAO, we expect the memory
recovery work is finished correctly, then the get_dump_page() will not
return the error page as its process pte is set invalid by
memory_failure().

But memory_failure() may fail, and the process's related pte may not be
correctly set invalid, for current code, we will return the poison page,
get it dumped, and then lead to system panic as its in kernel code.

So check the poison status in get_dump_page(), and if TRUE, return NULL.

There maybe other scenario that is also better to check the posion status
and not to panic, so make a wrapper for this check, Thanks to David's
suggestion().

[akpm@linux-foundation.org: s/0/false/]
[yaoaili@kingsoft.com: is_page_poisoned() arg cannot be null, per Matthew]

Link: https://lkml.kernel.org/r/20210322115233.05e4e82a@alex-virtual-machine
Link: https://lkml.kernel.org/r/20210319104437.6f30e80d@alex-virtual-machine
Signed-off-by: Aili Yao 
Cc: David Hildenbrand 
Cc: Matthew Wilcox 
Cc: Naoya Horiguchi 
Cc: Oscar Salvador 
Cc: Mike Kravetz 
Cc: Aili Yao 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

percpu: make pcpu_nr_empty_pop_pages per chunk type

2021-04-09T13:58:38+00:00

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: 3c7be18ac9a0 ("mm: memcg/percpu: account percpu memory to memory cgroups")
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Roman Gushchin 
Tested-by: Filipe Manana 
Signed-off-by: Dennis Zhou