INFO: rcu detected stall in dev_ioctl (3)

Status: upstream: reported on 2026/07/22 13:58
Reported-by: syzbot+16ed04d7d295763e4a7e@syzkaller.appspotmail.com
First crash: 38d, last: 1d16h
▶ ▼ Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in dev_ioctl (2) 1 1 26d 26d 0/3 upstream: reported on 2026/08/02 22:47
linux-5.15 INFO: rcu detected stall in dev_ioctl (2) 1 5 154d 258d 0/3 auto-obsoleted due to no activity on 2026/07/05 19:56
linux-4.19 INFO: rcu detected stall in dev_ioctl 1 1 2188d 2188d 0/1 auto-closed as invalid on 2020/12/30 14:33
linux-6.1 INFO: rcu detected stall in dev_ioctl 1 2 145d 146d 0/3 auto-obsoleted due to no activity on 2026/07/15 04:42
linux-4.19 INFO: rcu detected stall in dev_ioctl (2) 1 1 1826d 1826d 0/1 auto-closed as invalid on 2021/12/27 14:21
upstream INFO: rcu detected stall in dev_ioctl batman 1 18 1601d 2468d 0/29 auto-closed as invalid on 2022/08/09 13:29
linux-4.19 INFO: rcu detected stall in dev_ioctl (3) 1 1 1703d 1703d 0/1 auto-closed as invalid on 2022/04/29 15:27
linux-6.6 INFO: rcu detected stall in dev_ioctl (2) 1 1 20d 20d 0/2 upstream: reported on 2026/08/09 04:57
linux-6.1 BUG: soft lockup in dev_ioctl 1 6 246d 404d 0/3 auto-obsoleted due to no activity on 2026/04/05 06:22
linux-5.15 INFO: rcu detected stall in dev_ioctl 1 1 635d 635d 0/3 auto-obsoleted due to no activity on 2025/03/11 17:46
linux-6.6 INFO: rcu detected stall in dev_ioctl 1 1 369d 369d 0/2 auto-obsoleted due to no activity on 2025/12/02 20:33
upstream INFO: rcu detected stall in dev_ioctl (2) mm 1 3 600d 684d 0/29 auto-obsoleted due to no activity on 2025/04/05 21:09
upstream BUG: soft lockup in dev_ioctl (2) mm 1 6 303d 372d 0/29 auto-obsoleted due to no activity on 2026/02/07 12:10
upstream BUG: soft lockup in dev_ioctl batman 1 2 836d 901d 0/29 auto-obsoleted due to no activity on 2024/08/13 06:45
android-5-15 BUG: soft lockup in dev_ioctl 1 7 764d 854d 0/2 auto-obsoleted due to no activity on 2024/10/24 08:58

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (6 ticks this GP) idle=99b/1/0x4000000000000002 softirq=15798/15798 fqs=0 
	(detected by 1, t=10502 jiffies, g=21065, q=1045)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7042 Comm: syz.1.597 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x13/0x60 kernel/kcov.c:206
Code: 48 8b 3d 80 01 12 0c 48 89 de 5b e9 a7 5f 44 00 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d 14 60 89 7e 65 8b 15 15 60 89 7e <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00
RSP: 0018:ffffc90000007818 EFLAGS: 00000046
RAX: ffffffff8184f7e2 RBX: ffff8880b9033d78 RCX: ffff888024e7d940
RDX: 0000000000010101 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000078d8 R08: ffff8880b903b1fb R09: 1ffff1101720763f
R10: dffffc0000000000 R11: ffffed1017207640 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff92000000f08
FS:  00007f7ef02fd6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000023c0 CR3: 0000000066848000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 irq_work_run_list+0x2f2/0x340 kernel/irq_work.c:172
 __sysvec_irq_work+0x98/0x240 arch/x86/kernel/irq_work.c:22
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0x4a/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 f2 0f 9d 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900000079c0 EFLAGS: 00000206
RAX: fab28477fa2b5c00 RBX: 1ffff92000000f3c RCX: fab28477fa2b5c00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a43c0
RBP: ffffc90000007aa0 R08: ffffffff901ef1bf R09: 1ffffffff203de37
R10: dffffc0000000000 R11: fffffbfff203de38 R12: ffffffff8c323400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 hsr_announce+0x29a/0x310 net/hsr/hsr_device.c:410
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> ef 90 88 f7 65 8b 05 60 a8 38 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900030cf560 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: fab28477fa2b5c00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001
RBP: ffffc900030cf5f0 R08: ffffffff901ef0c7 R09: 1ffffffff203de18
R10: dffffc0000000000 R11: fffffbfff203de19 R12: dffffc0000000000
R13: 0000000000069c70 R14: ffffffff8c3c9120 R15: 1ffff92000619eac
 spin_unlock_irqrestore include/linux/spinlock.h:419 [inline]
 pcpu_alloc+0xb8e/0x16d0 mm/percpu.c:1850
 qdisc_alloc+0x3bb/0xae0 net/sched/sch_generic.c:906
 qdisc_create_dflt+0x5f/0x410 net/sched/sch_generic.c:953
 mq_init+0x2c4/0x650 net/sched/sch_mq.c:90
 qdisc_create_dflt+0x11a/0x410 net/sched/sch_generic.c:960
 attach_default_qdiscs net/sched/sch_generic.c:1139 [inline]
 dev_activate+0x192/0x1330 net/sched/sch_generic.c:1193
 __dev_open+0x33b/0x430 net/core/dev.c:1559
 __dev_change_flags+0x1e4/0x6a0 net/core/dev.c:8879
 dev_change_flags+0x78/0x1a0 net/core/dev.c:8950
 dev_ifsioc+0x130/0xd50 net/core/dev_ioctl.c:324
 dev_ioctl+0x545/0xe30 net/core/dev_ioctl.c:572
 sock_do_ioctl+0x245/0x320 net/socket.c:1162
 sock_ioctl+0x48a/0x700 net/socket.c:1267
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7ef20a50d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7ef02fd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7ef232cfa0 RCX: 00007f7ef20a50d9
RDX: 0000200000000200 RSI: 0000000000008914 RDI: 000000000000000d
RBP: 00007f7ef213c024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7ef232d038 R14: 00007f7ef232cfa0 R15: 00007fff0e05ce68
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g21065 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=11586
rcu: rcu_preempt kthread starved for 10502 jiffies! g21065 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:27536 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7042 Comm: syz.1.597 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5366 [inline]
RIP: 0010:lock_is_held_type+0x9b/0x190 kernel/locking/lockdep.c:5666
Code: 4b 0e 00 00 65 ff 05 34 22 42 76 83 bb e8 0a 00 00 00 7e 4b 44 89 fd 49 89 df 49 81 c7 f0 0a 00 00 45 31 e4 49 83 fc 31 73 24 <4c> 89 ff 4c 89 f6 e8 fa 01 00 00 85 c0 75 2a 49 ff c4 48 63 83 e8
RSP: 0018:ffffc90000007210 EFLAGS: 00000097
RAX: 0000000000000000 RBX: ffff888024e7d940 RCX: fab28477fa2b5c00
RDX: 0000000000000100 RSI: ffffffff8a2b39e0 RDI: ffffffff8a7a43c0
RBP: 00000000ffffffff R08: ffffc900000073f7 R09: ffffc900000073c0
R10: dffffc0000000000 R11: fffff52000000e7f R12: 0000000000000000
R13: 0000000000000046 R14: ffffffff8c31ef60 R15: ffff888024e7e430
FS:  00007f7ef02fd6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000023c0 CR3: 0000000066848000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 perf_get_guest_cbs include/linux/perf_event.h:1274 [inline]
 perf_misc_flags+0x56/0x1b0 arch/x86/events/core.c:2961
 perf_prepare_sample+0x132/0x1cb0 kernel/events/core.c:7632
 __perf_event_output kernel/events/core.c:7812 [inline]
 perf_event_output_forward+0x185/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 f2 0f 9d 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900000079c0 EFLAGS: 00000206
RAX: fab28477fa2b5c00 RBX: 1ffff92000000f3c RCX: fab28477fa2b5c00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a43c0
RBP: ffffc90000007aa0 R08: ffffffff901ef1bf R09: 1ffffffff203de37
R10: dffffc0000000000 R11: fffffbfff203de38 R12: ffffffff8c323400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 hsr_announce+0x29a/0x310 net/hsr/hsr_device.c:410
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> ef 90 88 f7 65 8b 05 60 a8 38 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900030cf560 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: fab28477fa2b5c00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001
RBP: ffffc900030cf5f0 R08: ffffffff901ef0c7 R09: 1ffffffff203de18
R10: dffffc0000000000 R11: fffffbfff203de19 R12: dffffc0000000000
R13: 0000000000069c70 R14: ffffffff8c3c9120 R15: 1ffff92000619eac
 spin_unlock_irqrestore include/linux/spinlock.h:419 [inline]
 pcpu_alloc+0xb8e/0x16d0 mm/percpu.c:1850
 qdisc_alloc+0x3bb/0xae0 net/sched/sch_generic.c:906
 qdisc_create_dflt+0x5f/0x410 net/sched/sch_generic.c:953
 mq_init+0x2c4/0x650 net/sched/sch_mq.c:90
 qdisc_create_dflt+0x11a/0x410 net/sched/sch_generic.c:960
 attach_default_qdiscs net/sched/sch_generic.c:1139 [inline]
 dev_activate+0x192/0x1330 net/sched/sch_generic.c:1193
 __dev_open+0x33b/0x430 net/core/dev.c:1559
 __dev_change_flags+0x1e4/0x6a0 net/core/dev.c:8879
 dev_change_flags+0x78/0x1a0 net/core/dev.c:8950
 dev_ifsioc+0x130/0xd50 net/core/dev_ioctl.c:324
 dev_ioctl+0x545/0xe30 net/core/dev_ioctl.c:572
 sock_do_ioctl+0x245/0x320 net/socket.c:1162
 sock_ioctl+0x48a/0x700 net/socket.c:1267
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7ef20a50d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7ef02fd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7ef232cfa0 RCX: 00007f7ef20a50d9
RDX: 0000200000000200 RSI: 0000000000008914 RDI: 000000000000000d
RBP: 00007f7ef213c024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7ef232d038 R14: 00007f7ef232cfa0 R15: 00007fff0e05ce68
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/28 01:36 linux-5.15.y 4a1eaf96ee5c 69a01293 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2026/08/15 15:56 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2026/07/27 00:49 linux-5.15.y 674f684f7c61 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2026/07/22 13:57 linux-5.15.y c86c4726e7f0 4a865b71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
* Struck through repros no longer work on HEAD.