INFO: task hung in netdev_run_todo (2)

Status: premoderation: reported on 2026/01/22 03:02
Reported-by: syzbot+f4c9b9509664219a17ad@syzkaller.appspotmail.com
First crash: 227d, last: 22h21m
▶ ▼ Similar bugs (18)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in netdev_run_todo (3) 1 15 1399d 1715d 0/1 auto-obsoleted due to no activity on 2023/03/07 08:19
linux-6.6 INFO: task hung in netdev_run_todo 1 1 366d 366d 0/2 auto-obsoleted due to no activity on 2025/12/14 15:00
linux-5.15 INFO: task hung in netdev_run_todo (3) 1 1 254d 254d 0/3 auto-obsoleted due to no activity on 2026/04/05 15:48
upstream INFO: task hung in netdev_run_todo net 1 12 2573d 3128d 0/29 closed as invalid on 2019/10/23 07:29
linux-4.19 INFO: task hung in netdev_run_todo (2) 1 3 2206d 2254d 0/1 auto-closed as invalid on 2020/12/20 04:57
linux-5.15 INFO: task hung in netdev_run_todo (4) 1 syz 2 17d 22d 0/3 upstream: reported syz repro on 2026/08/15 05:07
android-44 INFO: task hung in netdev_run_todo 1 1 3067d 3067d 0/2 auto-closed as invalid on 2019/02/22 12:49
upstream INFO: task hung in netdev_run_todo (4) prio:high wireguard 1 962 5h39m 697d 0/29 upstream: reported on 2024/10/09 19:06
linux-4.19 INFO: task hung in netdev_run_todo 1 1 2532d 2532d 0/1 auto-closed as invalid on 2020/01/29 06:48
upstream INFO: task hung in netdev_run_todo (3) net 1 24 810d 848d 0/29 auto-obsoleted due to no activity on 2024/08/07 04:24
linux-5.15 INFO: task hung in netdev_run_todo 1 1 1045d 1045d 0/3 auto-obsoleted due to no activity on 2024/02/04 09:09
linux-6.6 INFO: task hung in netdev_run_todo (2) 1 1 234d 234d 0/2 auto-obsoleted due to no activity on 2026/04/24 20:32
upstream INFO: task hung in netdev_run_todo (2) staging wireguard usb 1 syz, C error 241 936d 2093d 0/29 auto-obsoleted due to no activity on 2024/05/05 22:51
android-49 INFO: task hung in netdev_run_todo 1 1 3060d 3060d 0/3 auto-closed as invalid on 2019/02/22 14:57
linux-4.14 INFO: task hung in netdev_run_todo 1 1 1393d 1393d 0/1 auto-obsoleted due to no activity on 2023/03/13 17:45
android-6-12 INFO: task hung in netdev_run_todo 1 184 296d 441d 0/1 auto-obsoleted due to no activity on 2026/01/03 01:56
linux-5.15 INFO: task hung in netdev_run_todo (2) 1 54 657d 839d 0/3 auto-obsoleted due to no activity on 2025/01/26 20:30
upstream INFO: task can't die in netdev_run_todo net 1 syz error 2 1815d 2208d 0/29 auto-obsoleted due to no activity on 2023/04/16 04:59

Sample crash report:
INFO: task syz.1.22:418 blocked for more than 124 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.22        state:D stack:0     pid:418   tgid:418   ppid:295    flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8032
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 rcu_barrier+0x4d/0x580 kernel/rcu/tree.c:4589
 netdev_run_todo+0x118/0xce0 net/core/dev.c:10912
 rtnl_unlock+0x12/0x20 net/core/rtnetlink.c:152
 tun_detach drivers/net/tun.c:704 [inline]
 tun_chr_close+0xc5/0x150 drivers/net/tun.c:3520
 __fput+0x208/0xa30 fs/file_table.c:447
 ____fput+0x20/0x30 fs/file_table.c:475
 task_work_run+0x1e5/0x260 kernel/task_work.c:246
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa46/0x2850 kernel/exit.c:955
 do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
 get_signal+0x134c/0x1490 kernel/signal.c:2933
 arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x57/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f69e555e98e
RSP: 002b:00007f69e63cff58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f69e63d06c0 RCX: 00007f69e555e98e
RDX: 00007f69e63cffb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f69e5635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f69e5826308 R14: 00007f69e5826270 R15: 00007fffe56a37d8
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 1f46b48b3a0ef7537d643c2c4b1d5e30032b8167
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c4/0x360 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 1f46b48b3a0ef7537d643c2c4b1d5e30032b8167
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:stack_trace_consume_entry+0x0/0x2a0 kernel/stacktrace.c:83
Code: 8d 65 f0 5b 41 5e 5d c3 cc cc cc cc cc e8 e8 47 2f 04 0f 1f 84 00 00 00 00 00 b8 59 a6 4f c1 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 20 48
RSP: 0018:ffffc90000007580 EFLAGS: 00000257
RAX: ffffffff847af8d8 RBX: ffffc90000007640 RCX: 0000000000000e00
RDX: ffffc90000007901 RSI: ffffffff847af8d8 RDI: ffffc90000007640
RBP: ffffc90000007610 R08: ffffc90000007650 R09: ffffc90000007648
R10: 0000000000000000 R11: ffffffff8175a5e0 R12: ffff888102650000
R13: 0000000000000000 R14: ffffffff8175a5e0 R15: ffffc90000007588
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0ffaa26038 CR3: 00000001342f8000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:49 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
 kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:249 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2445 [inline]
 slab_free mm/slub.c:4714 [inline]
 kmem_cache_free+0x1bd/0x4f0 mm/slub.c:4825
 kfree_skbmem net/core/skbuff.c:-1 [inline]
 __kfree_skb+0x18f/0x210 net/core/skbuff.c:1205
 sk_skb_reason_drop+0xd8/0x310 net/core/skbuff.c:1242
 kfree_skb_reason include/linux/skbuff.h:1303 [inline]
 kfree_skb include/linux/skbuff.h:1312 [inline]
 ip6_mc_input+0x433/0x680 net/ipv6/ip6_input.c:587
 dst_input include/net/dst.h:469 [inline]
 ip6_rcv_finish+0x341/0x3c0 net/ipv6/ip6_input.c:79
 NF_HOOK include/linux/netfilter.h:317 [inline]
 ipv6_rcv+0xf1/0x240 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core net/core/dev.c:5801 [inline]
 __netif_receive_skb net/core/dev.c:5914 [inline]
 process_backlog+0x472/0xaf0 net/core/dev.c:6250
 __napi_poll+0xd0/0x600 net/core/dev.c:6901
 napi_poll net/core/dev.c:6970 [inline]
 net_rx_action+0x5dc/0xd70 net/core/dev.c:7092
 handle_softirqs+0x1aa/0x620 kernel/softirq.c:621
 __do_softirq+0xf/0x16 kernel/softirq.c:659
 do_softirq+0xb8/0x110 kernel/softirq.c:503
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
 __raw_write_unlock_bh include/linux/rwlock_api_smp.h:281 [inline]
 _raw_write_unlock_bh+0x33/0x70 kernel/locking/spinlock.c:366
 neigh_periodic_work+0xa6a/0xbb0 net/core/neighbour.c:1024
 process_one_work kernel/workqueue.c:3273 [inline]
 process_scheduled_works+0x7f4/0x1060 kernel/workqueue.c:3354
 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
 kthread+0x2c4/0x360 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
net_ratelimit: 102097 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:96:04:88:f5:88:4e, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:96:04:88:f5:88:4e, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
net_ratelimit: 129376 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:96:04:88:f5:88:4e, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:96:04:88:f5:88:4e, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (134):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/05 21:03 android16-6.12 4e585dd7f3b7 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/09/04 04:16 android16-6.12 1eab233d5fae 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/09/03 11:46 android16-6.12 8473ff8a565c 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/09/01 12:32 android16-6.12 77b3c87e00dc 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/29 18:09 android16-6.12 36bee94a7cf9 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/29 10:01 android16-6.12 36bee94a7cf9 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/28 14:30 android16-6.12 3ebc81d80f95 e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/28 02:05 android16-6.12 3ebc81d80f95 69a01293 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/24 17:17 android16-6.12 e8c85685a629 b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/17 15:54 android16-6.12 b21af26d1628 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/14 09:35 android16-6.12 c3360dde0a9e b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/08/06 22:33 android16-6.12 749a6f9d41aa c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/31 07:30 android16-6.12 7d66c8550304 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/29 22:12 android16-6.12 f1c9c21d1c2f 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/27 23:39 android16-6.12 a12ab5a23a35 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/27 06:55 android16-6.12 579215f16d4e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/23 04:37 android16-6.12 6599be6df4d0 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/22 20:12 android16-6.12 b739cd4ffbe5 4a865b71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/21 05:43 android16-6.12 5aeb3ef16d03 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/20 18:01 android16-6.12 c3f9cafa739b de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/19 18:02 android16-6.12 0fd55a309793 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/18 09:09 android16-6.12 0fd55a309793 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/14 13:45 android16-6.12 5dd528d5e93a 2130f682 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/14 03:40 android16-6.12 5dd528d5e93a 2130f682 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/11 10:45 android16-6.12 0026e4ecedf0 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/10 01:01 android16-6.12 0e0925f37543 4167ee25 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/07 20:16 android16-6.12 68c198f6d8bc 76cdc0c0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/05 18:40 android16-6.12 d36feda1de57 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/07/03 19:12 android16-6.12 d36feda1de57 58bf2096 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/28 13:18 android16-6.12 220923cf9f76 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/28 08:28 android16-6.12 220923cf9f76 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/27 07:21 android16-6.12 220923cf9f76 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/27 00:14 android16-6.12 220923cf9f76 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/26 10:50 android16-6.12 cc87569b5721 7ff32d8b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/25 23:13 android16-6.12 cc87569b5721 7ff32d8b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/25 06:21 android16-6.12 f222c1f727d9 cfa969bf .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/25 00:52 android16-6.12 f222c1f727d9 302586aa .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/23 19:09 android16-6.12 8f68185b8289 4b1d8f01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/23 12:28 android16-6.12 8f68185b8289 4b1d8f01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/22 03:43 android16-6.12 8f68185b8289 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/21 06:50 android16-6.12 8f68185b8289 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/18 12:15 android16-6.12 8f68185b8289 a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/17 14:45 android16-6.12 8f68185b8289 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/16 04:02 android16-6.12 8f68185b8289 50bb0618 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/14 22:09 android16-6.12 8f68185b8289 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
2026/06/13 17:29 android16-6.12 8f68185b8289 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in netdev_run_todo
* Struck through repros no longer work on HEAD.