[moderation] [perf?] KCSAN: data-race in __perf_event_read_value / perf_event_set_state (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 07d9df80082b Merge tag 'perf-tools-fixes-for-v6.17-2025-08..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b8bef0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=86a2212b48ce4ce2
dashboard link: https://syzkaller.appspot.com/bug?extid=636eed5293f727855034
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
CC: [ac...@kernel.org adrian...@intel.com alexander...@linux.intel.com iro...@google.com jo...@kernel.org kan....@linux.intel.com linux-...@vger.kernel.org linux-pe...@vger.kernel.org mark.r...@arm.com mi...@redhat.com namh...@kernel.org pet...@infradead.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4d171f55c84c/disk-07d9df80.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a98c7e116e81/vmlinux-07d9df80.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7681910e0d3d/bzImage-07d9df80.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+636eed...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __perf_event_read_value / perf_event_set_state

write to 0xffff88811a486400 of 8 bytes by task 9207 on cpu 0:
__perf_update_times kernel/events/core.c:-1 [inline]
perf_event_update_time kernel/events/core.c:734 [inline]
perf_event_set_state+0x195/0x440 kernel/events/core.c:753
event_sched_out+0x2d4/0x4d0 kernel/events/core.c:2393
group_sched_out kernel/events/core.c:2417 [inline]
__pmu_ctx_sched_out+0x3e7/0x530 kernel/events/core.c:3460
ctx_sched_out+0x273/0x2d0 kernel/events/core.c:3541
task_ctx_sched_out+0x4d/0x70 kernel/events/core.c:2861
perf_event_context_sched_out kernel/events/core.c:3748 [inline]
__perf_event_task_sched_out+0x286/0x370 kernel/events/core.c:3848
perf_event_task_sched_out include/linux/perf_event.h:1654 [inline]
prepare_task_switch kernel/sched/core.c:5155 [inline]
context_switch kernel/sched/core.c:5304 [inline]
__schedule+0xaf8/0xb30 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x5f/0xd0 kernel/sched/core.c:7058
futex_do_wait kernel/futex/waitwake.c:358 [inline]
__futex_wait+0x117/0x260 kernel/futex/waitwake.c:687
futex_wait+0x9d/0x1d0 kernel/futex/waitwake.c:715
do_futex+0x2bf/0x380 kernel/futex/syscalls.c:102
__do_sys_futex kernel/futex/syscalls.c:179 [inline]
__se_sys_futex+0x2ed/0x360 kernel/futex/syscalls.c:160
__x64_sys_futex+0x78/0x90 kernel/futex/syscalls.c:160
x64_sys_call+0x2e39/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:203
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811a486400 of 8 bytes by task 9220 on cpu 1:
__perf_event_read_value+0x82/0x1d0 kernel/events/core.c:5893
perf_read_one kernel/events/core.c:6050 [inline]
__perf_read kernel/events/core.c:6103 [inline]
perf_read+0x173/0x4d0 kernel/events/core.c:6120
loop_rw_iter+0x2c6/0x3f0 include/linux/uio.h:-1
io_iter_do_read io_uring/rw.c:830 [inline]
__io_read+0xbcb/0xc20 io_uring/rw.c:941
io_read+0x1c/0x60 io_uring/rw.c:1020
__io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1773
io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1796
io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1908
io_worker_handle_work+0x44e/0x9b0 io_uring/io-wq.c:650
io_wq_worker+0x22e/0x870 io_uring/io-wq.c:704
ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000006293c98 -> 0x0000000006294ed0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 9220 Comm: iou-wrk-9207 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================


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[syzbot]

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