[moderation] [perf?] KCSAN: data-race in detach_pid / perf_event_switch_output (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0f1dd5e91e2b Merge tag 'sound-6.8-rc5' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17822f68180000
kernel config: https://syzkaller.appspot.com/x/.config?x=b4c8befe72e5ccb8
dashboard link: https://syzkaller.appspot.com/bug?extid=9ed7c5c8ebb64eed58da
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ac...@kernel.org adrian...@intel.com alexander...@linux.intel.com iro...@google.com jo...@kernel.org 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/ddb8b90b7d02/disk-0f1dd5e9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fe61736c8374/vmlinux-0f1dd5e9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f6f025bacd89/bzImage-0f1dd5e9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9ed7c5...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in detach_pid / perf_event_switch_output

write to 0xffff8881429fc6c8 of 8 bytes by task 2025 on cpu 1:
__change_pid kernel/pid.c:350 [inline]
detach_pid+0xdb/0x160 kernel/pid.c:361
__unhash_process kernel/exit.c:130 [inline]
__exit_signal kernel/exit.c:202 [inline]
release_task+0x6c3/0xc20 kernel/exit.c:259
wait_task_zombie kernel/exit.c:1182 [inline]
wait_consider_task+0x1165/0x1670 kernel/exit.c:1409
do_wait_thread kernel/exit.c:1472 [inline]
__do_wait+0xff/0x4f0 kernel/exit.c:1590
do_wait+0xae/0x270 kernel/exit.c:1624
kernel_wait4+0x15f/0x1c0 kernel/exit.c:1783
__do_sys_wait4 kernel/exit.c:1811 [inline]
__se_sys_wait4 kernel/exit.c:1807 [inline]
__x64_sys_wait4+0x94/0x120 kernel/exit.c:1807
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881429fc6c8 of 8 bytes by task 13285 on cpu 0:
pid_alive include/linux/pid.h:261 [inline]
perf_event_pid_type kernel/events/core.c:1334 [inline]
perf_event_pid kernel/events/core.c:1341 [inline]
perf_event_switch_output+0x19e/0x390 kernel/events/core.c:9050
perf_iterate_sb_cpu kernel/events/core.c:7992 [inline]
perf_iterate_sb+0x353/0x640 kernel/events/core.c:8021
perf_event_switch kernel/events/core.c:9097 [inline]
__perf_event_task_sched_in+0x72e/0x790 kernel/events/core.c:4015
perf_event_task_sched_in include/linux/perf_event.h:1484 [inline]
finish_task_switch+0x212/0x2a0 kernel/sched/core.c:5269
context_switch kernel/sched/core.c:5403 [inline]
__schedule+0x5d8/0x920 kernel/sched/core.c:6727
__schedule_loop kernel/sched/core.c:6802 [inline]
schedule+0x54/0x80 kernel/sched/core.c:6817
worker_thread+0x5fb/0x730 kernel/workqueue.c:2802
kthread+0x1d7/0x210 kernel/kthread.c:388
ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

value changed: 0xffff88813a1b1380 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13285 Comm: kworker/u4:3 Tainted: G W 6.8.0-rc4-syzkaller-00267-g0f1dd5e91e2b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: 0x0 (bat_events)
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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