INFO: rcu detected stall in compat_sys_mq_open

Status: auto-obsoleted due to no activity on 2026/08/21 22:40
Subsystems: mm
Labels: prio:low
[Documentation on labels]
First crash: 93d, last: 93d
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ID Workflow Result Correct Bug Created Started Finished Revision
68867d31 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ INFO: rcu detected stall in compat_sys_mq_open 2026/06/02 06:41 2026/06/02 06:41 2026/06/02 07:37 1095583b

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6510/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=19581, q=2548 ncpus=2)
task:syz.2.238       state:R  running task     stack:28128 pid:6510  tgid:6504  ppid:5643   task_flags:0x400040 flags:0x08080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 f1 ad 07 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 db e8 97 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 40 a1 0a 0a cc 48 8d 3d 88 8d 92
RSP: 0018:ffffc900037af598 EFLAGS: 00000282
RAX: 870208618f0b5500 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000074397c20 RSI: ffffffff8e220627 RDI: ffffffff8c28b660
RBP: ffffffff8176e256 R08: ffffffff8176e256 R09: ffffffff8e95cca0
R10: ffffc900037af6f8 R11: ffffffff81b0e020 R12: 0000000000000002
R13: ffffffff8e95cca0 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 rcu_read_lock include/linux/rcupdate.h:838 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
 __slab_free+0x274/0x2c0 mm/slub.c:5613
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_lru_noprof+0x2b8/0x640 mm/slub.c:4918
 __d_alloc+0x37/0x6f0 fs/dcache.c:1807
 d_alloc+0x4b/0x190 fs/dcache.c:1886
 lookup_one_qstr_excl+0xd8/0x360 fs/namei.c:1801
 __start_dirop fs/namei.c:2916 [inline]
 start_dirop fs/namei.c:2938 [inline]
 start_creating_noperm+0x80/0xb0 fs/namei.c:3517
 mqueue_file_open ipc/mqueue.c:896 [inline]
 do_mq_open+0x246/0x7d0 ipc/mqueue.c:924
 __do_compat_sys_mq_open ipc/mqueue.c:1503 [inline]
 __se_compat_sys_mq_open ipc/mqueue.c:1493 [inline]
 __ia32_compat_sys_mq_open+0x22a/0x290 ipc/mqueue.c:1493
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x229/0x6e0 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fc401c
RSP: 002b:00000000f546550c EFLAGS: 00000206 ORIG_RAX: 0000000000000115
RAX: ffffffffffffffda RBX: 0000000080000a00 RCX: 0000000000000042
RDX: 00000000000001f0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/23 22:33 upstream 79bd2dded182 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: rcu detected stall in compat_sys_mq_open
* Struck through repros no longer work on HEAD.