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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 47ac09b91bef Linux 6.11-rc4
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13a369f5980000
kernel config: https://syzkaller.appspot.com/x/.config?x=3aa0f597417bf8c7
dashboard link: https://syzkaller.appspot.com/bug?extid=be1275ceca3c8cba5965
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org hu...@google.com linux-...@vger.kernel.org linu...@kvack.org]

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/df4c88184d31/disk-47ac09b9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7866414be00a/vmlinux-47ac09b9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/423eb5ba2509/bzImage-47ac09b9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+be1275...@syzkaller.appspotmail.com

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

write to 0xffff8881085e5910 of 8 bytes by task 3713 on cpu 1:
__percpu_counter_limited_add+0x3df/0x450 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:228
shmem_alloc_and_add_folio mm/shmem.c:1814 [inline]
shmem_get_folio_gfp+0x5e2/0xd80 mm/shmem.c:2188
shmem_get_folio mm/shmem.c:2293 [inline]
shmem_write_begin+0xa0/0x1c0 mm/shmem.c:2898
generic_perform_write+0x1b4/0x580 mm/filemap.c:4019
shmem_file_write_iter+0xc8/0xf0 mm/shmem.c:3074
__kernel_write_iter+0x24f/0x4e0 fs/read_write.c:523
dump_emit_page fs/coredump.c:893 [inline]
dump_user_range+0x3a7/0x550 fs/coredump.c:954
elf_core_dump+0x1aeb/0x1c30 fs/binfmt_elf.c:2116
do_coredump+0xfa7/0x1810 fs/coredump.c:767
get_signal+0xdc1/0x1080 kernel/signal.c:2902
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
irqentry_exit_to_user_mode+0x9a/0x130 kernel/entry/common.c:231
irqentry_exit+0x12/0x50 kernel/entry/common.c:334
exc_general_protection+0x33d/0x4d0 arch/x86/kernel/traps.c:644
asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:617

read to 0xffff8881085e5910 of 8 bytes by task 3649 on cpu 0:
__percpu_counter_limited_add+0xfa/0x450
percpu_counter_limited_add include/linux/percpu_counter.h:77 [inline]
shmem_inode_acct_blocks+0xf5/0x230 mm/shmem.c:228
shmem_alloc_and_add_folio mm/shmem.c:1814 [inline]
shmem_get_folio_gfp+0x5e2/0xd80 mm/shmem.c:2188
shmem_get_folio mm/shmem.c:2293 [inline]
shmem_write_begin+0xa0/0x1c0 mm/shmem.c:2898
generic_perform_write+0x1b4/0x580 mm/filemap.c:4019
shmem_file_write_iter+0xc8/0xf0 mm/shmem.c:3074
__kernel_write_iter+0x24f/0x4e0 fs/read_write.c:523
dump_emit_page fs/coredump.c:893 [inline]
dump_user_range+0x3a7/0x550 fs/coredump.c:954
elf_core_dump+0x1aeb/0x1c30 fs/binfmt_elf.c:2116
do_coredump+0xfa7/0x1810 fs/coredump.c:767
get_signal+0xdc1/0x1080 kernel/signal.c:2902
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
irqentry_exit_to_user_mode+0x9a/0x130 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: 0x00000000000034da -> 0x00000000000034fb

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3649 Comm: syz.4.378 Not tainted 6.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================
syz.4.378 (3649) used greatest stack depth: 10520 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.