BUG: soft lockup in ip_rcv

Status: upstream: reported C repro on 2025/10/25 08:20
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+3b38c7160feac2d51a83@syzkaller.appspotmail.com
First crash: 332d, last: 255d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2025/10/26 lts (merge base) f97f1002271b C [report] BUG: soft lockup in smp_call_function
2026/09/20 lts (merge base) [unknown] C Failed due to an error; will retry later
2025/10/26 upstream (ToT) 72761a7e3122 C Didn't crash
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in ip_rcv (7) net modules 1 3 276d 416d 0/29 auto-obsoleted due to no activity on 2026/03/20 17:26
linux-4.19 BUG: soft lockup in ip_rcv 1 syz, C error 16 1299d 1967d 0/1 upstream: reported C repro on 2021/05/04 03:32
linux-4.14 BUG: soft lockup in ip_rcv (2) 1 1 2004d 2004d 0/1 auto-closed as invalid on 2021/07/26 15:49
upstream INFO: rcu detected stall in ip_rcv (6) netfilter 1 4 520d 663d 0/29 auto-obsoleted due to no activity on 2025/07/19 18:54
linux-4.14 BUG: soft lockup in ip_rcv 1 1 2166d 2166d 0/1 auto-closed as invalid on 2021/02/14 05:25
linux-4.14 BUG: soft lockup in ip_rcv (3) 1 syz, C error 4 1479d 1599d 0/1 upstream: reported C repro on 2022/05/07 10:08
upstream INFO: rcu detected stall in ip_rcv (3) kernel 1 1 1983d 1983d 0/29 auto-closed as invalid on 2021/07/17 18:11
upstream INFO: rcu detected stall in ip_rcv (4) net bpf 1 12 1610d 1681d 0/29 auto-closed as invalid on 2022/07/25 09:18
upstream INFO: rcu detected stall in ip_rcv (5) net 1 2 1124d 1137d 0/29 auto-obsoleted due to no activity on 2023/11/23 01:36
▶ ▼ Last patch testing requests (7)
Created Duration User Patch Repo Result
2026/09/13 23:36 13m retest repro android14-6.1 job log log
2026/09/13 23:36 14m retest repro android14-6.1 report job log log
2026/08/20 10:50 3m retest repro android14-6.1 error job log
2026/07/05 23:47 13m retest repro android14-6.1 log
2026/06/16 04:33 24m retest repro android14-6.1 log
2026/06/16 04:33 20m retest repro android14-6.1 log
2026/05/28 11:08 2h22m retest repro android14-6.1 log
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2026/02/09 00:55 0m bisect fix android14-6.1 error job log
2026/01/09 22:11 2h29m bisect fix android14-6.1 OK (0) job log log
2025/11/25 20:04 1h57m bisect fix android14-6.1 OK (0) job log log

Sample crash report:
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000823d2c31f
R10: 0000001b31d20000 R11: 0000000000000246 R12: 00007faa1c9e5fac
R13: 00007faa1c9e5fa0 R14: ffffffffffffffff R15: 0000000000000003
 </TASK>
watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [syz.2.3030:3445]
Modules linked in:
CPU: 1 PID: 3445 Comm: syz.2.3030 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0xf2/0x140 arch/x86/kernel/kvm.c:1064
Code: 96 13 04 f4 eb 9a fa 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 3f 0f b6 07 40 38 f0 75 10 66 90 0f 00 2d 30 96 13 04 fb f4 <e9> 71 ff ff ff fb e9 6b ff ff ff e8 de 16 b9 03 89 f9 80 e1 07 38
RSP: 0018:ffffc900001b04c0 EFLAGS: 00000246
RAX: 0000000000000003 RBX: ffff88811fbb1498 RCX: ffffffff84f48de2
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88811fbb1498
RBP: ffffc900001b0550 R08: dffffc0000000000 R09: ffffed1023f76294
R10: ffffed1023f76294 R11: 1ffff11023f76293 R12: 1ffff1103ee20001
R13: ffff8881f7138cd4 R14: dffffc0000000000 R15: 1ffff92000036098
FS:  0000555556be8500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000012e957000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 pv_wait arch/x86/include/asm/paravirt.h:603 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x690/0xc40 kernel/locking/qspinlock.c:511
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline]
 queued_spin_lock_slowpath+0x47/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
 _raw_spin_lock+0xd8/0xe0 kernel/locking/spinlock.c:154
 tcp_v4_rcv+0x224e/0x2a80 net/ipv4/tcp_ipv4.c:2110
 ip_protocol_deliver_rcu+0x325/0x6e0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x24e/0x410 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ip_local_deliver+0x1d8/0x320 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:463 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:449 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ip_rcv+0x163/0x270 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core net/core/dev.c:5597 [inline]
 __netif_receive_skb+0xd7/0x2a0 net/core/dev.c:5711
 process_backlog+0x351/0x600 net/core/dev.c:6039
 __napi_poll+0xd0/0x5e0 net/core/dev.c:6606
 napi_poll net/core/dev.c:6673 [inline]
 net_rx_action+0x49b/0xaa0 net/core/dev.c:6787
 handle_softirqs+0x1d7/0x600 kernel/softirq.c:642
 __do_softirq kernel/softirq.c:680 [inline]
 invoke_softirq kernel/softirq.c:497 [inline]
 __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:csd_lock_wait kernel/smp.c:453 [inline]
RIP: 0010:smp_call_function_many_cond+0x878/0x960 kernel/smp.c:998
Code: e6 01 31 ff e8 99 65 09 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 0a e8 65 61 09 00 e9 38 ff ff ff f3 90 41 0f b6 44 1d 00 <84> c0 75 14 41 f7 07 01 00 00 00 0f 84 1a ff ff ff e8 42 61 09 00
RSP: 0018:ffffc90001c577c0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88812c83a880
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90001c578f8 R08: dffffc0000000000 R09: ffffed103ee2721b
R10: 0000000000000000 R11: ffffffff81343830 R12: 1ffff1103ee27218
R13: 1ffff1103ee07ae1 R14: 0000000000000000 R15: ffff8881f703d708
 on_each_cpu_cond_mask+0x43/0x80 kernel/smp.c:1165
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
 text_poke_bp_batch+0x1cc/0x580 arch/x86/kernel/alternative.c:1774
 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
 text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:1972
 arch_jump_label_transform_apply+0x15/0x30 arch/x86/kernel/jump_label.c:146
 __jump_label_update+0x37c/0x3a0 kernel/jump_label.c:451
 jump_label_update+0x39b/0x450 kernel/jump_label.c:797
 static_key_disable_cpuslocked+0xc9/0x1a0 kernel/jump_label.c:203
 static_key_disable+0x1a/0x30 kernel/jump_label.c:211
 tracepoint_remove_func kernel/tracepoint.c:417 [inline]
 tracepoint_probe_unregister+0x624/0x8b0 kernel/tracepoint.c:551
 bpf_probe_unregister+0x61/0x70 kernel/trace/bpf_trace.c:2359
 bpf_raw_tp_link_release+0x63/0x90 kernel/bpf/syscall.c:3170
 bpf_link_free+0x13a/0x390 kernel/bpf/syscall.c:2739
 bpf_link_put kernel/bpf/syscall.c:2765 [inline]
 bpf_link_release+0x15f/0x170 kernel/bpf/syscall.c:2774
 __fput+0x1fc/0x8f0 fs/file_table.c:320
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x1db/0x240 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7faa1c78f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd23d2c028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000003ea5c RCX: 00007faa1c78f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000823d2c31f
R10: 0000001b31d20000 R11: 0000000000000246 R12: 00007faa1c9e5fac
R13: 00007faa1c9e5fa0 R14: ffffffffffffffff R15: 0000000000000003
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 19 Comm: kworker/0:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: rcu_gp srcu_invoke_callbacks
RIP: 0010:native_halt arch/x86/include/asm/irqflags.h:57 [inline]
RIP: 0010:halt arch/x86/include/asm/irqflags.h:98 [inline]
RIP: 0010:kvm_wait+0xcc/0x140 arch/x86/kernel/kvm.c:1058
Code: 20 f6 44 24 21 02 75 24 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 48 0f b6 07 40 38 f0 75 a6 66 90 0f 00 2d 55 96 13 04 f4 <eb> 9a fa 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 3f 0f b6 07
RSP: 0018:ffffc90000006a00 EFLAGS: 00000046
RAX: 0000000000000003 RBX: ffff8881f7027c40 RCX: ffffffff84f48de2
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff8881f7027c40
RBP: ffffc90000006a90 R08: dffffc0000000000 R09: ffffed103ee04f89
R10: ffffed103ee04f89 R11: 1ffff1103ee04f88 R12: 1ffff1103ee00001
R13: ffff8881f7038cd4 R14: dffffc0000000000 R15: 1ffff92000000d40
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000115284000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 pv_wait arch/x86/include/asm/paravirt.h:603 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x690/0xc40 kernel/locking/qspinlock.c:511
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline]
 queued_spin_lock_slowpath+0x47/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0x108/0x110 kernel/locking/spinlock.c:162
 lock_timer_base+0x127/0x270 kernel/time/timer.c:1005
 __mod_timer+0xe5/0xbf0 kernel/time/timer.c:1086
 add_timer+0x68/0x80 kernel/time/timer.c:1250
 __queue_delayed_work+0x173/0x200 kernel/workqueue.c:1686
 queue_delayed_work_on+0xdb/0x150 kernel/workqueue.c:1711
 queue_delayed_work include/linux/workqueue.h:525 [inline]
 schedule_delayed_monitor_work kernel/rcu/tree.c:3216 [inline]
 kvfree_call_rcu+0x436/0x7a0 kernel/rcu/tree.c:3472
 trie_delete_elem+0x572/0x720 kernel/bpf/lpm_trie.c:545
 bpf_prog_41385012b43a9f2e+0x40/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:987 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline]
 bpf_trace_run3+0x113/0x270 kernel/trace/bpf_trace.c:2323
 __bpf_trace_timer_start+0x2b/0x40 include/trace/events/timer.h:53
 trace_timer_start include/trace/events/timer.h:53 [inline]
 enqueue_timer+0x337/0x480 kernel/time/timer.c:615
 __mod_timer+0x84a/0xbf0 kernel/time/timer.c:-1
 mod_timer+0x1f/0x30 kernel/time/timer.c:1196
 sk_reset_timer+0x22/0xb0 net/core/sock.c:3395
 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:-1 [inline]
 tcp_reset_xmit_timer include/net/tcp.h:1366 [inline]
 tcp_rearm_rto+0x312/0x700 net/ipv4/tcp_input.c:3264
 tcp_event_new_data_sent+0x250/0x400 net/ipv4/tcp_output.c:82
 tcp_write_xmit+0x161f/0x5fb0 net/ipv4/tcp_output.c:2717
 __tcp_push_pending_frames+0x9c/0x2f0 net/ipv4/tcp_output.c:2895
 tcp_push_pending_frames include/net/tcp.h:1987 [inline]
 tcp_data_snd_check net/ipv4/tcp_input.c:5605 [inline]
 tcp_rcv_established+0xed9/0x1a20 net/ipv4/tcp_input.c:6029
 tcp_v4_do_rcv+0x446/0xa10 net/ipv4/tcp_ipv4.c:1683
 tcp_v4_rcv+0x233c/0x2a80 net/ipv4/tcp_ipv4.c:2114
 ip_protocol_deliver_rcu+0x325/0x6e0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x24e/0x410 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ip_local_deliver+0x1d8/0x320 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:463 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:449 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ip_rcv+0x163/0x270 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core net/core/dev.c:5597 [inline]
 __netif_receive_skb+0xd7/0x2a0 net/core/dev.c:5711
 process_backlog+0x351/0x600 net/core/dev.c:6039
 __napi_poll+0xd0/0x5e0 net/core/dev.c:6606
 napi_poll net/core/dev.c:6673 [inline]
 net_rx_action+0x49b/0xaa0 net/core/dev.c:6787
 handle_softirqs+0x1d7/0x600 kernel/softirq.c:642
 __do_softirq+0xb/0xd kernel/softirq.c:680
 do_softirq+0xc6/0x120 kernel/softirq.c:524
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x75/0x80 kernel/softirq.c:448
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 srcu_invoke_callbacks+0x1cf/0x410 kernel/rcu/srcutree.c:1597
 process_one_work+0x71f/0xc40 kernel/workqueue.c:2302
 worker_thread+0xa29/0x11f0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/07 14:17 android14-6.1 5ddae867b428 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf BUG: soft lockup in ip_rcv
2025/10/25 23:51 android14-6.1 22c0b7236c43 c0460fcd .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 BUG: soft lockup in ip_rcv
2025/10/25 23:27 android14-6.1 22c0b7236c43 c0460fcd .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf BUG: soft lockup in ip_rcv
2025/10/25 08:19 android14-6.1 22c0b7236c43 c0460fcd .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 BUG: soft lockup in ip_rcv
* Struck through repros no longer work on HEAD.