INFO: rcu detected stall in netif_receive_skb_list_internal

Status: upstream: reported on 2026/09/20 20:54
Reported-by: syzbot+058fdbe2e8d53684dab9@syzkaller.appspotmail.com
First crash: 24d, last: 24d
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in netif_receive_skb_list_internal 1 1 118d 118d 0/3 auto-obsoleted due to no activity on 2026/09/26 09:29

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10500 ticks this GP) idle=f8f/1/0x4000000000000000 softirq=47738/47738 fqs=0 
	(t=10500 jiffies g=62097 q=8345)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g62097 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=47756
rcu: rcu_preempt kthread starved for 10500 jiffies! g62097 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:27216 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:
NMI backtrace for cpu 0
CPU: 0 PID: 17469 Comm: syz.4.2429 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_cpu_stall+0x31a/0x5f0 kernel/rcu/tree_stall.h:631
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ec/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 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: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 42 0b 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: 0000:ffffc900030af740 EFLAGS: 00000206
RAX: 97892c679abfa300 RBX: 1ffff92000615eec RCX: 97892c679abfa300
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: ffffc900030af820 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 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]
 netif_receive_skb_list_internal+0x961/0xbd0 net/core/dev.c:5786
 gro_normal_list net/core/dev.c:5939 [inline]
 napi_complete_done+0x37e/0x850 net/core/dev.c:6677
 virtqueue_napi_complete drivers/net/virtio_net.c:357 [inline]
 virtnet_poll+0x9b7/0xfb0 drivers/net/virtio_net.c:1627
 __napi_poll+0xbb/0x430 net/core/dev.c:7101
 napi_poll net/core/dev.c:7168 [inline]
 net_rx_action+0x522/0xa80 net/core/dev.c:7258
 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
 common_interrupt+0x5e/0xd0 arch/x86/kernel/irq.c:242
 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
RIP: 0033:0x7fdd71702159
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:00007fdd6f95a028 EFLAGS: 00000246
RAX: ffffffffffffffed RBX: 00007fdd71989fa0 RCX: 00007fdd71702159
RDX: 0000000000000030 RSI: 0000000000000029 RDI: 0000000000000006
RBP: 00007fdd7179906b R08: 00000000000033eb R09: 0000000000000000
R10: 0000200000000100 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdd7198a038 R14: 00007fdd71989fa0 R15: 00007ffef775ec88
 </TASK>
NMI backtrace for cpu 0
CPU: 0 PID: 17469 Comm: syz.4.2429 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0x22d/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31f/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ec/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 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: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 42 0b 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: 0000:ffffc900030af740 EFLAGS: 00000206
RAX: 97892c679abfa300 RBX: 1ffff92000615eec RCX: 97892c679abfa300
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: ffffc900030af820 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 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]
 netif_receive_skb_list_internal+0x961/0xbd0 net/core/dev.c:5786
 gro_normal_list net/core/dev.c:5939 [inline]
 napi_complete_done+0x37e/0x850 net/core/dev.c:6677
 virtqueue_napi_complete drivers/net/virtio_net.c:357 [inline]
 virtnet_poll+0x9b7/0xfb0 drivers/net/virtio_net.c:1627
 __napi_poll+0xbb/0x430 net/core/dev.c:7101
 napi_poll net/core/dev.c:7168 [inline]
 net_rx_action+0x522/0xa80 net/core/dev.c:7258
 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
 common_interrupt+0x5e/0xd0 arch/x86/kernel/irq.c:242
 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
RIP: 0033:0x7fdd71702159
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:00007fdd6f95a028 EFLAGS: 00000246
RAX: ffffffffffffffed RBX: 00007fdd71989fa0 RCX: 00007fdd71702159
RDX: 0000000000000030 RSI: 0000000000000029 RDI: 0000000000000006
RBP: 00007fdd7179906b R08: 00000000000033eb R09: 0000000000000000
R10: 0000200000000100 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdd7198a038 R14: 00007fdd71989fa0 R15: 00007ffef775ec88
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/20 20:54 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in netif_receive_skb_list_internal
* Struck through repros no longer work on HEAD.