linux-stable.git/lib, branch v6.5.3

iov_iter: Fix iov_iter_extract_pages() with zero-sized entries

2023-09-13T07:53:55+00:00

commit f741bd7178c95abd7aeac5a9d933ee542f9a5509 upstream.

iov_iter_extract_pages() doesn't correctly handle skipping over initial
zero-length entries in ITER_KVEC and ITER_BVEC-type iterators.

The problem is that it accidentally reduces maxsize to 0 when it
skipping and thus runs to the end of the array and returns 0.

Fix this by sticking the calculated size-to-copy in a new variable
rather than back in maxsize.

Fixes: 7d58fe731028 ("iov_iter: Add a function to extract a page list from an iterator")
Signed-off-by: David Howells 
Reviewed-by: Christoph Hellwig 
Cc: Christian Brauner 
Cc: Jens Axboe 
Cc: Al Viro 
Cc: David Hildenbrand 
Cc: John Hubbard 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

XArray: Do not return sibling entries from xa_load()

2023-09-13T07:53:51+00:00

commit cbc02854331edc6dc22d8b77b6e22e38ebc7dd51 upstream.

It is possible for xa_load() to observe a sibling entry pointing to
another sibling entry.  An example:

Thread A:		Thread B:
			xa_store_range(xa, entry, 188, 191, gfp);
xa_load(xa, 191);
entry = xa_entry(xa, node, 63);
[entry is a sibling of 188]
			xa_store_range(xa, entry, 184, 191, gfp);
if (xa_is_sibling(entry))
offset = xa_to_sibling(entry);
entry = xa_entry(xas->xa, node, offset);
[entry is now a sibling of 184]

It is sufficient to go around this loop until we hit a non-sibling entry.
Sibling entries always point earlier in the node, so we are guaranteed
to terminate this search.

Signed-off-by: Matthew Wilcox (Oracle) 
Fixes: 6b24ca4a1a8d ("mm: Use multi-index entries in the page cache")
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

kunit: Fix checksum tests on big endian CPUs

2023-09-13T07:53:11+00:00

[ Upstream commit b38460bc463c54e0c15ff3b37e81f7e2059bb9bb ]

On powerpc64le checksum kunit tests work:

[    2.011457][    T1]     KTAP version 1
[    2.011662][    T1]     # Subtest: checksum
[    2.011848][    T1]     1..3
[    2.034710][    T1]     ok 1 test_csum_fixed_random_inputs
[    2.079325][    T1]     ok 2 test_csum_all_carry_inputs
[    2.127102][    T1]     ok 3 test_csum_no_carry_inputs
[    2.127202][    T1] # checksum: pass:3 fail:0 skip:0 total:3
[    2.127533][    T1] # Totals: pass:3 fail:0 skip:0 total:3
[    2.127956][    T1] ok 1 checksum

But on powerpc64 and powerpc32 they fail:

[    1.859890][    T1]     KTAP version 1
[    1.860041][    T1]     # Subtest: checksum
[    1.860201][    T1]     1..3
[    1.861927][   T58]     # test_csum_fixed_random_inputs: ASSERTION FAILED at lib/checksum_kunit.c:243
[    1.861927][   T58]     Expected result == expec, but
[    1.861927][   T58]         result == 54991 (0xd6cf)
[    1.861927][   T58]         expec == 33316 (0x8224)
[    1.863742][    T1]     not ok 1 test_csum_fixed_random_inputs
[    1.864520][   T60]     # test_csum_all_carry_inputs: ASSERTION FAILED at lib/checksum_kunit.c:267
[    1.864520][   T60]     Expected result == expec, but
[    1.864520][   T60]         result == 255 (0xff)
[    1.864520][   T60]         expec == 65280 (0xff00)
[    1.868820][    T1]     not ok 2 test_csum_all_carry_inputs
[    1.869977][   T62]     # test_csum_no_carry_inputs: ASSERTION FAILED at lib/checksum_kunit.c:306
[    1.869977][   T62]     Expected result == expec, but
[    1.869977][   T62]         result == 64515 (0xfc03)
[    1.869977][   T62]         expec == 0 (0x0)
[    1.872060][    T1]     not ok 3 test_csum_no_carry_inputs
[    1.872102][    T1] # checksum: pass:0 fail:3 skip:0 total:3
[    1.872458][    T1] # Totals: pass:0 fail:3 skip:0 total:3
[    1.872791][    T1] not ok 3 checksum

This is because all expected values were calculated for X86 which
is little endian. On big endian systems all precalculated 16 bits
halves must be byte swapped.

And this is confirmed by a huge amount of sparse errors when building
with C=2

So fix all sparse errors and it will naturally work on all endianness.

Fixes: 688eb8191b47 ("x86/csum: Improve performance of `csum_partial`")
Signed-off-by: Christophe Leroy 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

nmi_backtrace: allow excluding an arbitrary CPU

2023-09-13T07:53:08+00:00

[ Upstream commit 8d539b84f1e3478436f978ceaf55a0b6cab497b5 ]

The APIs that allow backtracing across CPUs have always had a way to
exclude the current CPU.  This convenience means callers didn't need to
find a place to allocate a CPU mask just to handle the common case.

Let's extend the API to take a CPU ID to exclude instead of just a
boolean.  This isn't any more complex for the API to handle and allows the
hardlockup detector to exclude a different CPU (the one it already did a
trace for) without needing to find space for a CPU mask.

Arguably, this new API also encourages safer behavior.  Specifically if
the caller wants to avoid tracing the current CPU (maybe because they
already traced the current CPU) this makes it more obvious to the caller
that they need to make sure that the current CPU ID can't change.

[akpm@linux-foundation.org: fix trigger_allbutcpu_cpu_backtrace() stub]
Link: https://lkml.kernel.org/r/20230804065935.v4.1.Ia35521b91fc781368945161d7b28538f9996c182@changeid
Signed-off-by: Douglas Anderson 
Acked-by: Michal Hocko 
Cc: kernel test robot 
Cc: Lecopzer Chen 
Cc: Petr Mladek 
Cc: Pingfan Liu 
Signed-off-by: Andrew Morton 
Stable-dep-of: 1f38c86bb29f ("watchdog/hardlockup: avoid large stack frames in watchdog_hardlockup_check()")
Signed-off-by: Sasha Levin

lib/clz_ctz.c: Fix clzdi2() and ctzdi2() for 32-bit kernels

2023-08-25T20:22:10+00:00

The gcc compiler translates on some architectures the 64-bit
__builtin_clzll() function to a call to the libgcc function __clzdi2(),
which should take a 64-bit parameter on 32- and 64-bit platforms.

But in the current kernel code, the built-in __clzdi2() function is
defined to operate (wrongly) on 32-bit parameters if BITS_PER_LONG ==
32, thus the return values on 32-bit kernels are in the range from
[0..31] instead of the expected [0..63] range.

This patch fixes the in-kernel functions __clzdi2() and __ctzdi2() to
take a 64-bit parameter on 32-bit kernels as well, thus it makes the
functions identical for 32- and 64-bit kernels.

This bug went unnoticed since kernel 3.11 for over 10 years, and here
are some possible reasons for that:

 a) Some architectures have assembly instructions to count the bits and
    which are used instead of calling __clzdi2(), e.g. on x86 the bsr
    instruction and on ppc cntlz is used. On such architectures the
    wrong __clzdi2() implementation isn't used and as such the bug has
    no effect and won't be noticed.

 b) Some architectures link to libgcc.a, and the in-kernel weak
    functions get replaced by the correct 64-bit variants from libgcc.a.

 c) __builtin_clzll() and __clzdi2() doesn't seem to be used in many
    places in the kernel, and most likely only in uncritical functions,
    e.g. when printing hex values via seq_put_hex_ll(). The wrong return
    value will still print the correct number, but just in a wrong
    formatting (e.g. with too many leading zeroes).

 d) 32-bit kernels aren't used that much any longer, so they are less
    tested.

A trivial testcase to verify if the currently running 32-bit kernel is
affected by the bug is to look at the output of /proc/self/maps:

Here the kernel uses a correct implementation of __clzdi2():

  root@debian:~# cat /proc/self/maps
  00010000-00019000 r-xp 00000000 08:05 787324     /usr/bin/cat
  00019000-0001a000 rwxp 00009000 08:05 787324     /usr/bin/cat
  0001a000-0003b000 rwxp 00000000 00:00 0          [heap]
  f7551000-f770d000 r-xp 00000000 08:05 794765     /usr/lib/hppa-linux-gnu/libc.so.6
  ...

and this kernel uses the broken implementation of __clzdi2():

  root@debian:~# cat /proc/self/maps
  0000000010000-0000000019000 r-xp 00000000 000000008:000000005 787324  /usr/bin/cat
  0000000019000-000000001a000 rwxp 000000009000 000000008:000000005 787324  /usr/bin/cat
  000000001a000-000000003b000 rwxp 00000000 00:00 0  [heap]
  00000000f73d1000-00000000f758d000 r-xp 00000000 000000008:000000005 794765  /usr/lib/hppa-linux-gnu/libc.so.6
  ...

Signed-off-by: Helge Deller 
Fixes: 4df87bb7b6a22 ("lib: add weak clz/ctz functions")
Cc: Chanho Min 
Cc: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # v3.11+
Signed-off-by: Linus Torvalds

Merge tag 'mm-hotfixes-stable-2023-08-25-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-25T18:44:43+00:00

Pull misc fixes from Andrew Morton:
 "18 hotfixes. 13 are cc:stable and the remainder pertain to post-6.4
  issues or aren't considered suitable for a -stable backport"

* tag 'mm-hotfixes-stable-2023-08-25-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  shmem: fix smaps BUG sleeping while atomic
  selftests: cachestat: catch failing fsync test on tmpfs
  selftests: cachestat: test for cachestat availability
  maple_tree: disable mas_wr_append() when other readers are possible
  madvise:madvise_free_pte_range(): don't use mapcount() against large folio for sharing check
  madvise:madvise_free_huge_pmd(): don't use mapcount() against large folio for sharing check
  madvise:madvise_cold_or_pageout_pte_range(): don't use mapcount() against large folio for sharing check
  mm: multi-gen LRU: don't spin during memcg release
  mm: memory-failure: fix unexpected return value in soft_offline_page()
  radix tree: remove unused variable
  mm: add a call to flush_cache_vmap() in vmap_pfn()
  selftests/mm: FOLL_LONGTERM need to be updated to 0x100
  nilfs2: fix general protection fault in nilfs_lookup_dirty_data_buffers()
  mm/gup: handle cont-PTE hugetlb pages correctly in gup_must_unshare() via GUP-fast
  selftests: cgroup: fix test_kmem_basic less than error
  mm: enable page walking API to lock vmas during the walk
  smaps: use vm_normal_page_pmd() instead of follow_trans_huge_pmd()
  mm/gup: reintroduce FOLL_NUMA as FOLL_HONOR_NUMA_FAULT

maple_tree: disable mas_wr_append() when other readers are possible

2023-08-24T21:59:47+00:00

The current implementation of append may cause duplicate data and/or
incorrect ranges to be returned to a reader during an update.  Although
this has not been reported or seen, disable the append write operation
while the tree is in rcu mode out of an abundance of caution.

During the analysis of the mas_next_slot() the following was
artificially created by separating the writer and reader code:

Writer:                                 reader:
mas_wr_append
    set end pivot
    updates end metata
    Detects write to last slot
    last slot write is to start of slot
    store current contents in slot
    overwrite old end pivot
                                        mas_next_slot():
                                                read end metadata
                                                read old end pivot
                                                return with incorrect range
    store new value

Alternatively:

Writer:                                 reader:
mas_wr_append
    set end pivot
    updates end metata
    Detects write to last slot
    last lost write to end of slot
    store value
                                        mas_next_slot():
                                                read end metadata
                                                read old end pivot
                                                read new end pivot
                                                return with incorrect range
    set old end pivot

There may be other accesses that are not safe since we are now updating
both metadata and pointers, so disabling append if there could be rcu
readers is the safest action.

Link: https://lkml.kernel.org/r/20230819004356.1454718-2-Liam.Howlett@oracle.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett 
Cc: 
Signed-off-by: Andrew Morton

radix tree: remove unused variable

2023-08-21T20:07:22+00:00

Recent versions of clang warn about an unused variable, though older
versions saw the 'slot++' as a use and did not warn:

radix-tree.c:1136:50: error: parameter 'slot' set but not used [-Werror,-Wunused-but-set-parameter]

It's clearly not needed any more, so just remove it.

Link: https://lkml.kernel.org/r/20230811131023.2226509-1-arnd@kernel.org
Fixes: 3a08cd52c37c7 ("radix tree: Remove multiorder support")
Signed-off-by: Arnd Bergmann 
Cc: Matthew Wilcox 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Peng Zhang 
Cc: Rong Tao 
Cc: Tom Rix 
Cc: 
Signed-off-by: Andrew Morton

Merge tag 'mm-hotfixes-stable-2023-08-11-13-44' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-11T21:19:20+00:00

Pull misc fixes from Andrew Morton:
 "14 hotfixes. 11 of these are cc:stable and the remainder address
  post-6.4 issues, or are not considered suitable for -stable
  backporting"

* tag 'mm-hotfixes-stable-2023-08-11-13-44' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/damon/core: initialize damo_filter->list from damos_new_filter()
  nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput
  selftests: cgroup: fix test_kmem_basic false positives
  fs/proc/kcore: reinstate bounce buffer for KCORE_TEXT regions
  MAINTAINERS: add maple tree mailing list
  mm: compaction: fix endless looping over same migrate block
  selftests: mm: ksm: fix incorrect evaluation of parameter
  hugetlb: do not clear hugetlb dtor until allocating vmemmap
  mm: memory-failure: avoid false hwpoison page mapped error info
  mm: memory-failure: fix potential unexpected return value from unpoison_memory()
  mm/swapfile: fix wrong swap entry type for hwpoisoned swapcache page
  radix tree test suite: fix incorrect allocation size for pthreads
  crypto, cifs: fix error handling in extract_iter_to_sg()
  zsmalloc: fix races between modifications of fullness and isolated

Merge tag 'wq-for-6.5-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2023-08-07T20:07:12+00:00

Pull workqueue fixes from Tejun Heo:

 - The recently added cpu_intensive auto detection and warning mechanism
   was spuriously triggered on slow CPUs.

   While not causing serious issues, it's still a nuisance and can cause
   unintended concurrency management behaviors.

   Relax the threshold on machines with lower BogoMIPS. While BogoMIPS
   is not an accurate measure of performance by most measures, we don't
   have to be accurate and it has rough but strong enough correlation.

 - A correction in Kconfig help text

* tag 'wq-for-6.5-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Scale up wq_cpu_intensive_thresh_us if BogoMIPS is below 4000
  workqueue: Fix cpu_intensive_thresh_us name in help text