syzbot
INFO: rcu detected stall in irqentry_exit (3)
Status: auto-obsoleted due to no activity on 2026/09/25 21:50
Subsystems:
kernel
Labels:
prio:high
[Documentation on labels]
First crash: 101d, last: 101d
Sample crash report:
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19055/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=93033, q=2236 ncpus=2)
task:syz.0.3451 state:R running task stack:25640 pid:19055 tgid:19055 ppid:17091 task_flags:0x400040 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7413
preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
__local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457
spin_unlock_bh include/linux/spinlock.h:396 [inline]
nl80211_netlink_notify+0x6f4/0x840 net/wireless/nl80211.c:22960
notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
netlink_release+0x11f8/0x1a80 net/netlink/af_netlink.c:762
__sock_release net/socket.c:710 [inline]
sock_close+0xad/0x220 net/socket.c:1501
__fput+0x418/0xa50 fs/file_table.c:512
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9fe5f9ce59
RSP: 002b:00007ffe10fb10b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f9fe6217da0 RCX: 00007f9fe5f9ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f9fe6217da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f9fe6217cb0 R11: 0000000000000246 R12: 000000000007d0ce
R13: 00007f9fe6215fac R14: 000000000007ce97 R15: 00007f9fe6215fa0
</TASK>
rcu: rcu_preempt kthread starved for 6685 jiffies! g93033 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 13970 Comm: kworker/R-bond7 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: 0x0 (bond7)
RIP: 0010:nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
RIP: 0010:nf_hook_slow+0x87/0x220 net/netfilter/core.c:619
Code: 89 e0 48 c1 e0 04 4d 8d 2c 07 49 83 c5 08 4c 89 3c 24 49 01 c7 49 83 c7 10 48 bd 00 00 00 00 00 fc ff df 4c 89 e8 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 ef e8 eb 55 62 f8 49 8b 5f f8 49 8d 7d 08
RSP: 0018:ffffc90000a07db0 EFLAGS: 00000a02
RAX: 1ffff1100b85c523 RBX: 0000000000000001 RCX: ffff888053f23e00
RDX: 0000000000000100 RSI: ffffffff8fe65ac0 RDI: 0000000000000001
RBP: dffffc0000000000 R08: ffff888053f23e00 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000100 R12: 0000000000000001
R13: ffff88805c2e2918 R14: 1ffff1100b85c520 R15: ffff88805c2e2920
FS: 0000000000000000(0000) GS:ffff888125326000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb0d1fe67e8 CR3: 000000005c0b6000 CR4: 00000000003526f0
Call Trace:
<IRQ>
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:316
br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:1165 [inline]
br_nf_forward_finish+0xa76/0xea0 net/bridge/br_netfilter_hooks.c:667
NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:318
br_nf_forward_ip+0x7eb/0xa30 net/bridge/br_netfilter_hooks.c:721
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:316
__br_forward+0x397/0x540 net/bridge/br_forward.c:115
br_handle_frame_finish+0x1175/0x1990 net/bridge/br_input.c:229
br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:318 [inline]
br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442
__netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6093
__netif_receive_skb_one_core net/core/dev.c:6204 [inline]
__netif_receive_skb net/core/dev.c:6319 [inline]
process_backlog+0x706/0x1860 net/core/dev.c:6670
__napi_poll+0xaa/0x330 net/core/dev.c:7729
napi_poll net/core/dev.c:7792 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:7949
handle_softirqs+0x225/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:finish_task_switch+0x417/0xc60 kernel/sched/core.c:5361
Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 a3 5a 21 0a e8 1e ac 39 00 fb 4c 8b 65 c8 <49> 8d bc 24 f8 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc90003657980 EFLAGS: 00000206
RAX: 0000000000120611 RBX: ffff8880b873bf20 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8dfe0307 RDI: ffffffff8c2a9f80
RBP: ffffc900036579d0 R08: ffffffff9032d2f7 R09: 1ffffffff2065a5e
R10: dffffc0000000000 R11: fffffbfff2065a5f R12: ffff888053f23e00
R13: ffff8880b873bee8 R14: dffffc0000000000 R15: 1ffff110170e77e4
context_switch kernel/sched/core.c:5513 [inline]
__schedule+0x17e1/0x56c0 kernel/sched/core.c:7234
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:rescuer_thread+0xd6f/0x10b0 kernel/workqueue.c:3663
Code: 44 24 78 0f b6 04 28 84 c0 4c 8b b4 24 d0 00 00 00 4c 8b bc 24 c8 00 00 00 0f 85 5a 01 00 00 48 8b 44 24 10 81 20 7f fe ff ff <48> 89 df e8 19 8c fe ff 48 c7 c7 20 6d 7f 8e e8 8d f9 26 0a 48 8b
RSP: 0018:ffffc90003657cf0 EFLAGS: 00000202
RAX: ffff88802ac24880 RBX: ffff888051aa5c00 RCX: 1ffff920006caf84
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: dffffc0000000000 R08: ffff888051f01f2b R09: 1ffff1100a3e03e5
R10: dffffc0000000000 R11: ffffed100a3e03e6 R12: ffff88802ac24868
R13: ffff88805a5e58b0 R14: ffff8880564698e0 R15: ffff888053f25670
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
net_ratelimit: 13545 callbacks suppressed
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:6e:a8:b5:7d:2b:55, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:6e:a8:b5:7d:2b:55, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:6e:a8:b5:7d:2b:55, vlan:0)
net_ratelimit: 16538 callbacks suppressed
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:6e:a8:b5:7d:2b:55, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:6e:a8:b5:7d:2b:55, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:6e:a8:b5:7d:2b:55, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
Struck through repros no longer work on HEAD.