linux-kernel - [syzbot] [kernel?] KCSAN: assert: race in dequeue

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Message-ID: <66f6c7d4.050a0220.38ace9.0026.GAE@google.com>
Date: Fri, 27 Sep 2024 07:57:24 -0700
From: syzbot <syzbot+0ec1e96c2cdf5c0e512a@...kaller.appspotmail.com>
To: audit@...r.kernel.org, eparis@...hat.com, linux-kernel@...r.kernel.org, 
	paul@...l-moore.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [kernel?] KCSAN: assert: race in dequeue_entities

Hello,

syzbot found the following issue on:

HEAD commit:    075dbe9f6e3c Merge tag 'soc-ep93xx-dt-6.12' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15f07a80580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=86254f9e0a8f2c98
dashboard link: https://syzkaller.appspot.com/bug?extid=0ec1e96c2cdf5c0e512a
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/1be80941df60/disk-075dbe9f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/494a9ac89c09/vmlinux-075dbe9f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/919788d8c731/bzImage-075dbe9f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0ec1e96c2cdf5c0e512a@...kaller.appspotmail.com

audit: type=1400 audit(6022412112.141:243086): avc:  denied  { read } for  pid=2950 comm="syslogd" name="log" dev="sda1" ino=1915 scontext=system_u:system_r:syslogd_t tcontext=system_u:object_r:var_t tclass=lnk_file permissive=0
audit: type=1400 audit(6022412112.181:243087): avc:  denied  { read } for  pid=2950 comm="syslogd" name="log" dev="sda1" ino=1915 scontext=system_u:system_r:syslogd_t tcontext=system_u:object_r:var_t tclass=lnk_file permissive=0
==================================================================
BUG: KCSAN: assert: race in __block_task kernel/sched/sched.h:2770 [inline]
BUG: KCSAN: assert: race in dequeue_entities+0x6df/0x760 kernel/sched/fair.c:7177

race at unknown origin, with assert no writes to 0xffff888101764268 of 4 bytes by task 29 on cpu 1:
 __block_task kernel/sched/sched.h:2770 [inline]
 dequeue_entities+0x6df/0x760 kernel/sched/fair.c:7177
 pick_next_entity kernel/sched/fair.c:5627 [inline]
 pick_task_fair kernel/sched/fair.c:8856 [inline]
 pick_next_task_fair+0x7d/0x410 kernel/sched/fair.c:8876
 __pick_next_task kernel/sched/core.c:5955 [inline]
 pick_next_task kernel/sched/core.c:6477 [inline]
 __schedule+0x284/0x940 kernel/sched/core.c:6629
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x55/0xc0 kernel/sched/core.c:6767
 kauditd_thread+0x56b/0x650 kernel/audit.c:911
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 29 Comm: kauditd Not tainted 6.11.0-syzkaller-11558-g075dbe9f6e3c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


---
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