syzbot

 sign-in | mailing list | source | docs
🐞 Open [815]
🐞 Fixed [85]
🐞 Invalid [1150]
⬇ Missing Backports [133]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in nsim_dev_trap_report_work (2)

Status: auto-obsoleted due to no activity on 2025/05/14 15:54
Reported-by: syzbot+c9150c4cef6bda8180b9@syzkaller.appspotmail.com
First crash: 314d, last: 314d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in nsim_dev_trap_report_work 1 2 527d 550d 0/3 auto-obsoleted due to no activity on 2024/10/13 18:52
upstream INFO: rcu detected stall in nsim_dev_trap_report_work (2) net 1 syz done 17 287d 775d 0/29 auto-obsoleted due to no activity on 2025/09/25 13:43
upstream INFO: rcu detected stall in nsim_dev_trap_report_work net 1 syz 4 830d 873d 23/29 fixed on 2023/10/12 12:48
linux-5.15 INFO: rcu detected stall in nsim_dev_trap_report_work (3) origin:lts-only 1 C 5 7d10h 117d 0/3 upstream: reported C repro on 2025/08/20 06:57
linux-6.1 INFO: rcu detected stall in nsim_dev_trap_report_work 1 2 580d 625d 0/3 auto-obsoleted due to no activity on 2024/08/22 01:13
linux-6.1 INFO: rcu detected stall in nsim_dev_trap_report_work (2) 1 1 234d 234d 0/3 auto-obsoleted due to no activity on 2025/08/03 09:20

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=0f7/1/0x4000000000000000 softirq=67657/67658 fqs=15 
	(detected by 0, t=10505 jiffies, g=92801, q=73)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11394 Comm: kworker/1:7 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:rcu_read_lock include/linux/rcupdate.h:740 [inline]
RIP: 0010:advance_sched+0x6ce/0x940 net/sched/sch_taprio.c:769
Code: 7d 18 49 83 c5 20 4c 89 e8 48 c1 e8 03 42 80 3c 30 00 74 08 4c 89 ef e8 70 d0 3d f9 4d 89 7d 00 e8 47 4d df f8 e8 42 f7 ff ff <e8> ed b6 b2 01 89 c3 31 ff 89 c6 e8 d2 ea f3 f8 85 db 74 10 e8 59
RSP: 0018:ffffc90000dd0cc0 EFLAGS: 00000086
RAX: 9d3a23f43f2c6b00 RBX: ffff888060253d20 RCX: 1ffff920001ba114
RDX: dffffc0000000000 RSI: ffffffff8aab3e20 RDI: ffffffff8af9f2c0
RBP: ffff888023661ae8 R08: dffffc0000000000 R09: fffffbfff2131821
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888023661800
R13: ffff888023661b60 R14: dffffc0000000000 R15: 182c2ae4b8000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3051bff8 CR3: 000000006777f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1688 [inline]
 __hrtimer_run_queues+0x598/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:__read_once_word_nocheck+0x0/0x10 include/asm-generic/rwonce.h:67
Code: e1 07 38 c1 0f 8c dc fc ff ff 48 89 df e8 68 9d 91 00 48 ba 00 00 00 00 00 fc ff df e9 c5 fc ff ff 66 0f 1f 84 00 00 00 00 00 <48> 8b 07 c3 cc cc cc cc cc cc cc cc cc cc cc cc 31 c0 81 ff 03 00
RSP: 0018:ffffc900030cf628 EFLAGS: 00000287
RAX: ffffc900030cfb30 RBX: ffffc900030cf720 RCX: 0000000000000000
RDX: ffffc900030cf760 RSI: ffffc900030cfb28 RDI: ffffc900030cfb28
RBP: ffffc900030d0000 R08: ffffc900030cfb28 R09: ffffc900030cf770
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffffc900030c8000 R14: ffffc900030cf760 R15: ffffc900030cfb28
 deref_stack_reg+0xbe/0x110 arch/x86/kernel/unwind_orc.c:360
 unwind_next_frame+0x12f1/0x1fa0
 arch_stack_walk+0x10d/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc+0xba/0xf0 mm/kasan/common.c:513
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 __kmalloc_node_track_caller+0x195/0x390 mm/slub.c:4963
 kmalloc_reserve net/core/skbuff.c:356 [inline]
 __alloc_skb+0x12c/0x590 net/core/skbuff.c:427
 alloc_skb include/linux/skbuff.h:1162 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
 nsim_dev_trap_report_work+0x25e/0xab0 drivers/net/netdevsim/dev.c:762
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10430 jiffies! g92801 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:26168 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 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:
NMI backtrace for cpu 0
CPU: 0 PID: 18851 Comm: kworker/0:15 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events jump_label_update_timeout
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
 update_process_times+0x196/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1688 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xa93/0xd90 kernel/smp.c:969
Code: 04 03 84 c0 0f 85 84 00 00 00 45 8b 7d 00 44 89 fe 83 e6 01 31 ff e8 3c d6 0b 00 41 83 e7 01 75 07 e8 d1 d2 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00
RSP: 0018:ffffc900048ef940 EFLAGS: 00000293
RAX: ffffffff8174b2e4 RBX: 1ffff110171e80b1 RCX: ffff888026025940
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900048efa80 R08: ffffffff8174b2b4 R09: fffffbfff2131821
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001
R13: ffff8880b8f40588 R14: ffff8880b8e3b380 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1207 [inline]
 text_poke_bp_batch+0x2b4/0x930 arch/x86/kernel/alternative.c:1407
 text_poke_flush arch/x86/kernel/alternative.c:1598 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1605
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 __static_key_slow_dec_cpuslocked+0x107/0x160 kernel/jump_label.c:248
 __static_key_slow_dec kernel/jump_label.c:255 [inline]
 jump_label_update_timeout+0x1a/0x20 kernel/jump_label.c:263
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/03 15:53 linux-5.15.y c16c81c81336 a21a8419 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in nsim_dev_trap_report_work
* Struck through repros no longer work on HEAD.