[moderation] [mm?] upstream test error: KCSAN: data-race in __percpu_counter_limited_add / __percpu_counter_limited_add (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c2ee9f594da8 KVM: selftests: Fix build on on non-x86 archi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12654640580000
kernel config: https://syzkaller.appspot.com/x/.config?x=91af2aaf073838b1
dashboard link: https://syzkaller.appspot.com/bug?extid=6740516279ee299c212a
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/c3513e5f30ec/disk-c2ee9f59.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9b7571304859/vmlinux-c2ee9f59.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b4ab71481c42/bzImage-c2ee9f59.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+674051...@syzkaller.appspotmail.com

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

write to 0xffff888104536490 of 8 bytes by task 3576 on cpu 0:
__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:1838 [inline]
shmem_get_folio_gfp+0x5be/0xd90 mm/shmem.c:2330
shmem_get_folio mm/shmem.c:2436 [inline]
shmem_write_begin+0xa2/0x180 mm/shmem.c:3041
generic_perform_write+0x1a8/0x4a0 mm/filemap.c:4054
shmem_file_write_iter+0xc2/0xe0 mm/shmem.c:3216
__kernel_write_iter+0x24b/0x4e0 fs/read_write.c:616
dump_emit_page fs/coredump.c:884 [inline]
dump_user_range+0x3a7/0x550 fs/coredump.c:945
elf_core_dump+0x1b66/0x1c60 fs/binfmt_elf.c:2121
do_coredump+0x1736/0x1ce0 fs/coredump.c:758
get_signal+0xdc0/0x1070 kernel/signal.c:2902
arch_do_signal_or_restart+0x95/0x4b0 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: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:693
asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:617

read to 0xffff888104536490 of 8 bytes by task 3529 on cpu 1:
__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:1838 [inline]
shmem_get_folio_gfp+0x5be/0xd90 mm/shmem.c:2330
shmem_get_folio mm/shmem.c:2436 [inline]
shmem_write_begin+0xa2/0x180 mm/shmem.c:3041
generic_perform_write+0x1a8/0x4a0 mm/filemap.c:4054
shmem_file_write_iter+0xc2/0xe0 mm/shmem.c:3216
__kernel_write_iter+0x24b/0x4e0 fs/read_write.c:616
dump_emit_page fs/coredump.c:884 [inline]
dump_user_range+0x3a7/0x550 fs/coredump.c:945
elf_core_dump+0x1b66/0x1c60 fs/binfmt_elf.c:2121
do_coredump+0x1736/0x1ce0 fs/coredump.c:758
get_signal+0xdc0/0x1070 kernel/signal.c:2902
arch_do_signal_or_restart+0x95/0x4b0 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: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: 0x0000000000003c54 -> 0x0000000000003c75

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3529 Comm: syz.2.248 Not tainted 6.12.0-rc4-syzkaller-00047-gc2ee9f594da8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
syz.2.248 (3529) used greatest stack depth: 10488 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.