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KCSAN: data-race in do_mq_timedreceive / do_mq_timedreceive (2)

Status: moderation: reported on 2025/10/14 03:38
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+ef0e42a6735945e1d74e@syzkaller.appspotmail.com
First crash: 1d03h, last: 1d03h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_mq_timedreceive / do_mq_timedreceive kernel 6 1 572d 572d 0/29 auto-obsoleted due to no activity on 2024/04/25 08:18

Sample crash report:
==================================================================
BUG: KCSAN: data-race in do_mq_timedreceive / do_mq_timedreceive

write to 0xffff888102274650 of 8 bytes by task 24558 on cpu 0:
 do_mq_timedreceive+0x29a/0x6d0 ipc/mqueue.c:1216
 __do_sys_mq_timedreceive ipc/mqueue.c:1283 [inline]
 __se_sys_mq_timedreceive ipc/mqueue.c:1272 [inline]
 __x64_sys_mq_timedreceive+0xc6/0x160 ipc/mqueue.c:1272
 x64_sys_call+0x290a/0x3000 arch/x86/include/generated/asm/syscalls_64.h:244
 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 0xffff888102274650 of 8 bytes by task 24547 on cpu 1:
 do_mq_timedreceive+0x201/0x6d0 ipc/mqueue.c:1208
 __do_sys_mq_timedreceive ipc/mqueue.c:1283 [inline]
 __se_sys_mq_timedreceive ipc/mqueue.c:1272 [inline]
 __x64_sys_mq_timedreceive+0xc6/0x160 ipc/mqueue.c:1272
 x64_sys_call+0x290a/0x3000 arch/x86/include/generated/asm/syscalls_64.h:244
 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

value changed: 0x0000000000000000 -> 0xffff88812fc81b00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 24547 Comm: syz.2.7452 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/14 03:37 upstream 3a8660878839 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in do_mq_timedreceive / do_mq_timedreceive
* Struck through repros no longer work on HEAD.