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: 68d, last: 23d
▶ ▼ 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 56d 56d 0/3 upstream: reported on 2026/08/02 22:47
linux-5.15 INFO: rcu detected stall in dev_ioctl (2) 1 5 184d 288d 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 2217d 2217d 0/1 auto-closed as invalid on 2020/12/30 14:33
linux-6.1 INFO: rcu detected stall in dev_ioctl 1 2 175d 175d 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 1855d 1855d 0/1 auto-closed as invalid on 2021/12/27 14:21
upstream INFO: rcu detected stall in dev_ioctl batman 1 18 1631d 2498d 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 1732d 1732d 0/1 auto-closed as invalid on 2022/04/29 15:27
linux-6.6 INFO: rcu detected stall in dev_ioctl (2) 1 2 2d15h 50d 0/2 upstream: reported on 2026/08/09 04:57
linux-6.1 BUG: soft lockup in dev_ioctl 1 6 276d 434d 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 665d 665d 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 399d 399d 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 630d 714d 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 333d 402d 0/29 auto-obsoleted due to no activity on 2026/02/07 12:10
upstream BUG: soft lockup in dev_ioctl batman 1 2 866d 931d 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 794d 883d 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-....: (193 ticks this GP) idle=9c3/1/0x4000000000000002 softirq=24421/24421 fqs=2142 
	(detected by 1, t=10506 jiffies, g=30941, q=2053)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10500 Comm: syz.4.1795 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:171 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2a/0x60 kernel/kcov.c:205
Code: 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 00 <74> 2c 8b 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b
RSP: 0018:ffffc90000006e08 EFLAGS: 00000046
RAX: ffffffff819bd956 RBX: 0000000000000001 RCX: ffff888027208000
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000006f50 R08: ffffc90000006ed7 R09: ffffc90000006ec0
R10: dffffc0000000000 R11: fffff52000000ddb R12: 1ffff92000000dd4
R13: ffffc90000006fa0 R14: dffffc0000000000 R15: ffff88808b8b2fc0
FS:  00007f25435d46c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1326009ff8 CR3: 000000007bcc5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_read_unlock+0x6/0x90 include/linux/rcupdate.h:768
 __perf_output_begin kernel/events/ring_buffer.c:262 [inline]
 perf_output_begin_forward+0x793/0xa30 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7814 [inline]
 perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_swevent_overflow kernel/events/core.c:9601 [inline]
 perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639
 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:ffffc900000075e0 EFLAGS: 00000206
RAX: 41d526f3f8a99900 RBX: 1ffff92000000ec0 RCX: 41d526f3f8a99900
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: ffffc900000076c0 R08: ffffffff901ef0cf R09: 1ffffffff203de19
R10: dffffc0000000000 R11: fffffbfff203de1a 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]
 is_bpf_text_address+0x24f/0x270 kernel/bpf/core.c:727
 kernel_text_address kernel/extable.c:151 [inline]
 __kernel_text_address+0x9a/0x100 kernel/extable.c:105
 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 rcu_do_batch kernel/rcu/tree.c:2523 [inline]
 rcu_core+0x96e/0x1650 kernel/rcu/tree.c:2763
 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:finish_lock_switch+0x12f/0x290 kernel/sched/core.c:4804
Code: 83 c7 18 be ff ff ff ff e8 0e 1b 6c 08 85 c0 74 46 4d 85 ff 75 62 0f 1f 44 00 00 48 89 df e8 c8 8a 75 08 e8 f3 df 2a 00 fb 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 2f 0e fe ff 43 80 3c 2c
RSP: 0018:ffffc9000331f938 EFLAGS: 00000286
RAX: 41d526f3f8a99900 RBX: ffff88807d18bb80 RCX: 41d526f3f8a99900
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: 1ffff11017207613 R08: ffffffff901ef0cf R09: 1ffffffff203de19
R10: dffffc0000000000 R11: fffffbfff203de1a R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
 finish_task_switch+0x12f/0x650 kernel/sched/core.c:4921
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11cb/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 dev_ioctl+0x5ce/0xe30 net/core/dev_ioctl.c:596
 sock_ioctl+0x679/0x700 net/socket.c:1192
 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: 0033:0x7f254537c159
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:00007f25435d4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2545603fa0 RCX: 00007f254537c159
RDX: 0000200000000080 RSI: 00000000000089f1 RDI: 0000000000000008
RBP: 00007f2545413024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2545604038 R14: 00007f2545603fa0 R15: 00007fffdd0c4fb8
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/04 21:42 linux-5.15.y 0996e0926f6b f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2026/09/04 04:21 linux-5.15.y 0996e0926f6b 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2026/08/28 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.