syzbot


INFO: rcu detected stall in dev_ioctl (2)

Status: upstream: reported on 2025/12/13 22:16
Reported-by: syzbot+500341fa036814fb4ce0@syzkaller.appspotmail.com
First crash: 115d, last: 11d
Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: rcu detected stall in dev_ioctl 1 1 2044d 2044d 0/1 auto-closed as invalid on 2020/12/30 14:33
linux-6.1 INFO: rcu detected stall in dev_ioctl 1 2 1d22h 2d10h 0/3 upstream: reported on 2026/04/05 17:14
linux-4.19 INFO: rcu detected stall in dev_ioctl (2) 1 1 1682d 1682d 0/1 auto-closed as invalid on 2021/12/27 14:21
upstream INFO: rcu detected stall in dev_ioctl batman 1 18 1457d 2325d 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 1559d 1559d 0/1 auto-closed as invalid on 2022/04/29 15:27
linux-6.1 BUG: soft lockup in dev_ioctl 1 6 102d 261d 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 492d 492d 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 226d 226d 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 457d 541d 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 159d 228d 0/29 auto-obsoleted due to no activity on 2026/02/07 12:10
upstream BUG: soft lockup in dev_ioctl batman 1 2 692d 758d 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 620d 710d 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-....: (1 GPs behind) idle=fa3/1/0x4000000000000000 softirq=29890/29891 fqs=5247 
	(detected by 1, t=10502 jiffies, g=42489, q=887)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11052 Comm: syz.2.2240 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:91 [inline]
RIP: 0010:lock_acquire+0x11f/0x400 kernel/locking/lockdep.c:5599
Code: 65 8b 05 74 78 a5 7e 85 c0 0f 85 43 01 00 00 65 4c 8b 35 e4 6e a5 7e 49 81 c6 ec 0a 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 08 02 00 00 41 83 3e 00 0f 85 16 01 00 00 43 c6 44 3d
RSP: 0018:ffffc900000076a0 EFLAGS: 00000803
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 4a15795e1bfe3200
RDX: 0000000000000000 RSI: ffffffff8a79f960 RDI: ffffffff8a79f920
RBP: ffffc900000077c0 R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d
R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: ffffffff8c31eaa0
R13: 1ffff92000000ee0 R14: ffff888026b0c66c R15: dffffc0000000000
FS:  00007f3d830946c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f32d57e5ff8 CR3: 00000000203e1000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 BPF_PROG_RUN_ARRAY include/linux/bpf.h:1431 [inline]
 trace_call_bpf+0xf9/0x5b0 kernel/trace/bpf_trace.c:127
 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10016
 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 12 f2 9c 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:ffffc90000007b00 EFLAGS: 00000206
RAX: 4a15795e1bfe3200 RBX: 1ffff92000000f64 RCX: 4a15795e1bfe3200
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980
RBP: ffffc90000007bd8 R08: ffffffff901d40cf R09: 1ffffffff203a819
R10: dffffc0000000000 R11: fffffbfff203a81a R12: ffffffff8c322f00
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]
 ieee80211_iterate_active_interfaces_atomic+0x132/0x140 net/mac80211/util.c:831
 mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
 handle_softirqs+0x339/0x830 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:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x13e/0x1c0 kernel/softirq.c:408
Code: 8a e8 a6 3c 73 08 65 66 8b 05 ae 5b ba 7e 66 85 c0 75 54 bf 01 00 00 00 e8 bf 24 09 00 e8 6a 0f 36 00 fb 65 8b 05 5a 32 b9 7e <85> c0 75 05 e8 a9 3f b7 ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc90002fff7c0 EFLAGS: 00000282
RAX: 0000000080000000 RBX: 0000000000000201 RCX: 4a15795e1bfe3200
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980
RBP: ffffc90002fff848 R08: ffffffff901d40cf R09: 1ffffffff203a819
R10: dffffc0000000000 R11: fffffbfff203a81a R12: ffffffff88011208
R13: ffff88801f5a6000 R14: dffffc0000000000 R15: 1ffff920005ffef8
 spin_unlock_bh include/linux/spinlock.h:409 [inline]
 dev_graft_qdisc+0xa8/0xc0 net/sched/sch_generic.c:1083
 mq_attach+0x117/0x240 net/sched/sch_mq.c:115
 attach_default_qdiscs net/sched/sch_generic.c:1142 [inline]
 dev_activate+0x20b/0x12b0 net/sched/sch_generic.c:1193
 __dev_open+0x33b/0x430 net/core/dev.c:1559
 __dev_change_flags+0x20d/0x6a0 net/core/dev.c:8879
 dev_change_flags+0x82/0x1a0 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:1161
 sock_ioctl+0x4d2/0x710 net/socket.c:1266
 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: 0033:0x7f3d84e3a799
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:00007f3d83094028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3d850b3fa0 RCX: 00007f3d84e3a799
RDX: 0000200000002280 RSI: 0000000000008914 RDI: 0000000000000009
RBP: 00007f3d84ed0c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3d850b4038 R14: 00007f3d850b3fa0 R15: 00007ffce98d5118
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/27 19:55 linux-5.15.y 91d48252ad4b 74a13a23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2026/03/24 05:22 linux-5.15.y 91d48252ad4b baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dev_ioctl
2026/01/02 16:05 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2025/12/23 00:38 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dev_ioctl
2025/12/13 22:16 linux-5.15.y 68efe5a6c16a d6526ea3 .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.