[syzbot] [bpf?] [trace?] KCSAN: data-race in __perf_event_overflow / perf_event_detach_bpf_prog

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fc02acf6ac0c Merge tag 'platform-drivers-x86-v7.2-4' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ad92a9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=84b3039e8461eef5
dashboard link: https://syzkaller.appspot.com/bug?extid=651d2774bd1d8395595f
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5213866cd074/disk-fc02acf6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e75f2151b444/vmlinux-fc02acf6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ea07b016de6c/bzImage-fc02acf6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+651d27...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __perf_event_overflow / perf_event_detach_bpf_prog

read-write to 0xffff88811afaeb68 of 8 bytes by task 22274 on cpu 0:
perf_event_detach_bpf_prog+0x115/0x180 kernel/trace/bpf_trace.c:2021
perf_event_free_bpf_prog+0x81/0x90 kernel/events/core.c:11766
bpf_perf_link_release+0x33/0x50 kernel/bpf/syscall.c:3997
bpf_link_free+0x9d/0x370 kernel/bpf/syscall.c:3395
bpf_link_put_direct kernel/bpf/syscall.c:3448 [inline]
bpf_link_release+0x45/0x60 kernel/bpf/syscall.c:3455
__fput+0x29e/0x630 fs/file_table.c:512
____fput+0x1c/0x30 fs/file_table.c:540
task_work_run+0x130/0x1a0 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1e4/0x8c0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811afaeb68 of 8 bytes by task 22278 on cpu 1:
__perf_event_overflow+0x230/0x940 kernel/events/core.c:10769
perf_swevent_overflow kernel/events/core.c:10911 [inline]
perf_swevent_event+0x3f3/0x4d0 kernel/events/core.c:10972
perf_tp_event+0x32f/0x1650 kernel/events/core.c:11484
perf_trace_run_bpf_submit+0xac/0x110 kernel/events/core.c:11403
do_perf_trace_sched_switch include/trace/events/sched.h:220 [inline]
perf_trace_sched_switch+0x186/0x1d0 include/trace/events/sched.h:220
__traceiter_sched_switch+0x3f/0x60 include/trace/events/sched.h:220
__do_trace_sched_switch include/trace/events/sched.h:220 [inline]
trace_sched_switch include/trace/events/sched.h:220 [inline]
__schedule+0xc23/0xd10 kernel/sched/core.c:7231
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x5a/0xa0 kernel/sched/core.c:7326
schedule_timeout+0x53/0x180 kernel/time/sleep_timeout.c:75
unix_wait_for_peer+0x135/0x1a0 net/unix/af_unix.c:1620
unix_dgram_sendmsg+0x8c2/0x1030 net/unix/af_unix.c:2256
sock_sendmsg_nosec net/socket.c:775 [inline]
__sock_sendmsg net/socket.c:790 [inline]
____sys_sendmsg+0x532/0x580 net/socket.c:2684
___sys_sendmsg+0x195/0x1e0 net/socket.c:2738
__sys_sendmmsg+0x185/0x320 net/socket.c:2827
__do_sys_sendmmsg net/socket.c:2854 [inline]
__se_sys_sendmmsg net/socket.c:2851 [inline]
__x64_sys_sendmmsg+0x57/0x70 net/socket.c:2851
x64_sys_call+0x27aa/0x3020 arch/x86/include/generated/asm/syscalls_64.h:308
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffc90002cb9000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 22278 Comm: syz.0.4075 Tainted: G W syzkaller #0 PREEMPT(lazy)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
==================================================================


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