[moderation] [perf?] KCSAN: data-race in perf_event_set_state / perf_event_update_time (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7ed2632ec7d7 drm/ttm: fix ttm pool initialization for no-d..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16165d9be80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bd33f45956bbc2
dashboard link: https://syzkaller.appspot.com/bug?extid=693eea9bb25bc10906d4
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/ff6facc21dca/disk-7ed2632e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/be6ef58407dd/vmlinux-7ed2632e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f18ed26c2f87/bzImage-7ed2632e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+693eea...@syzkaller.appspotmail.com

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

read to 0xffff88813a4340c0 of 8 bytes by task 8388 on cpu 0:
__perf_update_times kernel/events/core.c:628 [inline]
perf_event_update_time kernel/events/core.c:641 [inline]
perf_event_set_state+0x14b/0x3f0 kernel/events/core.c:660
event_sched_in+0xe2/0x670 kernel/events/core.c:2536
group_sched_in kernel/events/core.c:2584 [inline]
merge_sched_in kernel/events/core.c:3843 [inline]
visit_groups_merge+0xbe0/0x1bb0 kernel/events/core.c:3788
pmu_groups_sched_in kernel/events/core.c:3870 [inline]
ctx_groups_sched_in+0xa0/0x100 kernel/events/core.c:3883
ctx_sched_in+0x214/0x230 kernel/events/core.c:3937
perf_event_sched_in kernel/events/core.c:2680 [inline]
perf_event_context_sched_in kernel/events/core.c:3983 [inline]
__perf_event_task_sched_in+0x470/0x790 kernel/events/core.c:4012
perf_event_task_sched_in include/linux/perf_event.h:1484 [inline]
finish_task_switch+0x20e/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
exit_to_user_mode_loop kernel/entry/common.c:96 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
syscall_exit_to_user_mode+0x9d/0x130 kernel/entry/common.c:212
do_syscall_64+0x65/0x120 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b

write to 0xffff88813a4340c0 of 8 bytes by task 8463 on cpu 1:
perf_event_update_time+0x14d/0x1b0 kernel/events/core.c:641
perf_mmap+0xa36/0xcb0 kernel/events/core.c:6618
call_mmap include/linux/fs.h:2090 [inline]
mmap_region+0x9a1/0x1650 mm/mmap.c:2819
do_mmap+0x67e/0xa90 mm/mmap.c:1379
vm_mmap_pgoff+0x12e/0x240 mm/util.c:556
ksys_mmap_pgoff+0x2b8/0x330 mm/mmap.c:1425
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x000000000053fd0f -> 0x000000000076c7cf

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8463 Comm: syz-executor.0 Tainted: G W 6.8.0-rc1-syzkaller-00026-g7ed2632ec7d7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================


---
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.