[moderation] [mm?] upstream test error: KCSAN: data-race in __percpu_counter_limited_add / __percpu_counter_limited_add (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 834a4a689699 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14c8ea3f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=f723126dfc2a8a53
dashboard link: https://syzkaller.appspot.com/bug?extid=274ae93c409f71024b04
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org baoli...@linux.alibaba.com hu...@google.com linux-...@vger.kernel.org linu...@kvack.org]

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/62e06a0992ce/disk-834a4a68.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/391c18eea319/vmlinux-834a4a68.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc315a4e9596/bzImage-834a4a68.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+274ae9...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __percpu_counter_limited_add / __percpu_counter_limited_add

write to 0xffff888108baca90 of 8 bytes by task 3790 on cpu 1:
__percpu_counter_limited_add+0x3e4/0x460 lib/percpu_counter.c:386
percpu_counter_limited_add include/linux/percpu_counter.h:77 [inline]
shmem_inode_acct_blocks+0xf5/0x230 mm/shmem.c:233
shmem_alloc_and_add_folio mm/shmem.c:1923 [inline]
shmem_get_folio_gfp+0x5a2/0xd30 mm/shmem.c:2533
shmem_get_folio mm/shmem.c:2639 [inline]
shmem_write_begin+0xa7/0x190 mm/shmem.c:3289
generic_perform_write+0x189/0x4b0 mm/filemap.c:4102
shmem_file_write_iter+0xc2/0xe0 mm/shmem.c:3464
__kernel_write_iter+0x243/0x4c0 fs/read_write.c:617
dump_emit_page fs/coredump.c:885 [inline]
dump_user_range+0x5ed/0x8b0 fs/coredump.c:959
elf_core_dump+0x1d61/0x1ef0 fs/binfmt_elf.c:2128
do_coredump+0x1814/0x1f50 fs/coredump.c:759
get_signal+0xdb7/0x1080 kernel/signal.c:3019
arch_do_signal_or_restart+0x9a/0x4b0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
irqentry_exit_to_user_mode+0xa7/0x120 kernel/entry/common.c:231
irqentry_exit+0x12/0x50 kernel/entry/common.c:334
asm_exc_alignment_check+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffff888108baca90 of 8 bytes by task 3684 on cpu 0:
__percpu_counter_limited_add+0xfc/0x460 lib/percpu_counter.c:-1
percpu_counter_limited_add include/linux/percpu_counter.h:77 [inline]
shmem_inode_acct_blocks+0xf5/0x230 mm/shmem.c:233
shmem_alloc_and_add_folio mm/shmem.c:1923 [inline]
shmem_get_folio_gfp+0x5a2/0xd30 mm/shmem.c:2533
shmem_get_folio mm/shmem.c:2639 [inline]
shmem_write_begin+0xa7/0x190 mm/shmem.c:3289
generic_perform_write+0x189/0x4b0 mm/filemap.c:4102
shmem_file_write_iter+0xc2/0xe0 mm/shmem.c:3464
__kernel_write_iter+0x243/0x4c0 fs/read_write.c:617
dump_emit_page fs/coredump.c:885 [inline]
dump_user_range+0x5ed/0x8b0 fs/coredump.c:959
elf_core_dump+0x1d61/0x1ef0 fs/binfmt_elf.c:2128
do_coredump+0x1814/0x1f50 fs/coredump.c:759
get_signal+0xdb7/0x1080 kernel/signal.c:3019
arch_do_signal_or_restart+0x9a/0x4b0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
irqentry_exit_to_user_mode+0xa7/0x120 kernel/entry/common.c:231
irqentry_exit+0x12/0x50 kernel/entry/common.c:334
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x00000000000043ef -> 0x0000000000004410

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3684 Comm: syz.3.364 Not tainted 6.15.0-rc2-syzkaller-00037-g834a4a689699 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
syz.3.364 (3684) used greatest stack depth: 10440 bytes left


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.