linux-kernel - [syzbot] [perf?] KCSAN: data-race in _free_event / perf_pending

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Message-ID: <670cb595.050a0220.4cbc0.0043.GAE@google.com>
Date: Sun, 13 Oct 2024 23:09:25 -0700
From: syzbot <syzbot+e75157f5b04f8ff40e17@...kaller.appspotmail.com>
To: acme@...nel.org, adrian.hunter@...el.com, 
	alexander.shishkin@...ux.intel.com, irogers@...gle.com, jolsa@...nel.org, 
	kan.liang@...ux.intel.com, linux-kernel@...r.kernel.org, 
	linux-perf-users@...r.kernel.org, mark.rutland@....com, mingo@...hat.com, 
	namhyung@...nel.org, peterz@...radead.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [perf?] KCSAN: data-race in _free_event / perf_pending_task (2)

Hello,

syzbot found the following issue on:

HEAD commit:    87d6aab2389e Merge tag 'for_linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10104f9f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a2f7ae2f221e9eae
dashboard link: https://syzkaller.appspot.com/bug?extid=e75157f5b04f8ff40e17
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/cce40536bdc3/disk-87d6aab2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/479edc06c8d8/vmlinux-87d6aab2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9d377c65ffca/bzImage-87d6aab2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e75157f5b04f8ff40e17@...kaller.appspotmail.com

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

write to 0xffff8881155361e8 of 4 bytes by task 9574 on cpu 1:
 perf_pending_task+0xe8/0x220 kernel/events/core.c:6976
 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 0xffff8881155361e8 of 4 bytes by task 9573 on cpu 0:
 perf_pending_task_sync kernel/events/core.c:5302 [inline]
 _free_event+0x3d/0xa10 kernel/events/core.c:5326
 put_event kernel/events/core.c:5454 [inline]
 perf_event_release_kernel+0x61a/0x670 kernel/events/core.c:5579
 perf_release+0x1f/0x30 kernel/events/core.c:5589
 __fput+0x17a/0x6d0 fs/file_table.c:431
 ____fput+0x1c/0x30 fs/file_table.c:459
 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: 0x7ad100bf -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9573 Comm: syz.3.2265 Tainted: G        W          6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


---
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