[syzbot] [perf?] KCSAN: data-race in _free_event / perf_pending_task

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    94ede2a3e913 profiling: remove stale percpu flip buffer va..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1277094b980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bc4a9b665a33d32c
dashboard link: https://syzkaller.appspot.com/bug?extid=ef3b1bb7dd78b4e9109c
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/44ee867c2428/disk-94ede2a3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/94d1e02bfdfd/vmlinux-94ede2a3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/954c62ebb0b0/bzImage-94ede2a3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ef3b1bb7dd78b4e9109c@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KCSAN: data-race in _free_event / perf_pending_task

write to 0xffff88812715a1e8 of 4 bytes by task 22781 on cpu 1:
 perf_pending_task+0xe8/0x220 kernel/events/core.c:6869
 task_work_run+0x13a/0x1a0 kernel/task_work.c:228
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88812715a1e8 of 4 bytes by task 22780 on cpu 0:
 perf_pending_task_sync kernel/events/core.c:5199 [inline]
 _free_event+0x3d/0xa10 kernel/events/core.c:5223
 put_event kernel/events/core.c:5351 [inline]
 perf_event_release_kernel+0x61a/0x670 kernel/events/core.c:5476
 perf_release+0x25/0x30 kernel/events/core.c:5486
 __fput+0x192/0x6f0 fs/file_table.c:422
 ____fput+0x15/0x20 fs/file_table.c:450
 task_work_run+0x13a/0x1a0 kernel/task_work.c:228
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x7ad5cf52 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 22780 Comm: syz.3.5885 Not tainted 6.11.0-rc1-syzkaller-00043-g94ede2a3e913 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
==================================================================


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