INFO: task hung in netdev_run_todo (4)

Status: upstream: reported syz repro on 2026/08/15 05:07
Reported-by: syzbot+2271061f8b8e1bc1195e@syzkaller.appspotmail.com
First crash: 53d, last: 4d04h
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/09/18 upstream (ToT) 5dd1818b15d9 syz Didn't crash
▶ ▼ 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 1430d 1746d 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 396d 396d 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 284d 284d 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 2604d 3159d 0/29 closed as invalid on 2019/10/23 07:29
linux-4.19 INFO: task hung in netdev_run_todo (2) 1 3 2237d 2284d 0/1 auto-closed as invalid on 2020/12/20 04:57
android-44 INFO: task hung in netdev_run_todo 1 1 3098d 3098d 0/2 auto-closed as invalid on 2019/02/22 12:49
upstream INFO: task hung in netdev_run_todo (4) prio:high wireless 1 1008 21h30m 727d 0/29 upstream: reported on 2024/10/09 19:06
android-6-12 INFO: task hung in netdev_run_todo (2) 1 152 1d09h 258d 0/1 premoderation: reported on 2026/01/22 03:02
linux-4.19 INFO: task hung in netdev_run_todo 1 1 2563d 2563d 0/1 auto-closed as invalid on 2020/01/29 06:48
upstream INFO: task hung in netdev_run_todo (3) net 1 24 841d 878d 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 1076d 1076d 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 265d 265d 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 967d 2123d 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 3090d 3090d 0/3 auto-closed as invalid on 2019/02/22 14:57
linux-4.14 INFO: task hung in netdev_run_todo 1 1 1423d 1423d 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 327d 472d 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 688d 869d 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 1846d 2239d 0/29 auto-obsoleted due to no activity on 2023/04/16 04:59
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/09/11 01:22 26m retest repro linux-5.15.y report job log log

Sample crash report:
INFO: task kworker/u4:3:1173 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:3    state:D stack:21216 pid: 1173 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 netdev_run_todo+0x8dd/0xac0 net/core/dev.c:10722
 nsim_destroy+0xb2/0x150 drivers/net/netdevsim/netdev.c:387
 __nsim_dev_port_del+0x155/0x1c0 drivers/net/netdevsim/dev.c:1349
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1362 [inline]
 nsim_dev_reload_destroy+0x160/0x230 drivers/net/netdevsim/dev.c:1561
 nsim_dev_reload_down+0xf9/0x160 drivers/net/netdevsim/dev.c:883
 devlink_reload+0x253/0x770 net/core/devlink.c:3963
 devlink_pernet_pre_exit+0x1aa/0x310 net/core/devlink.c:11543
 ops_pre_exit_list net/core/net_namespace.c:162 [inline]
 cleanup_net+0x58e/0xba0 net/core/net_namespace.c:615
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task udevd:3557 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:25184 pid: 3557 ppid:     1 flags:0x00004002
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 device_lock include/linux/device.h:809 [inline]
 uevent_show+0x16c/0x320 drivers/base/core.c:2408
 dev_attr_show+0x50/0xb0 drivers/base/core.c:2110
 sysfs_kf_seq_show+0x316/0x4c0 fs/sysfs/file.c:61
 seq_read_iter+0x460/0xc50 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2173 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x75e/0xd50 fs/read_write.c:485
 ksys_read+0x153/0x260 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb8ac454407
RSP: 002b:00007ffc4ba532a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fb8ac366880 RCX: 00007fb8ac454407
RDX: 0000000000001000 RSI: 000055cb8620dc20 RDI: 000000000000000c
RBP: 00007fb8ac59cff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007fb8ac59cea0 R14: 0000000000000000 R15: 000055cb8620ca30
 </TASK>
INFO: task dhcpcd:3850 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:21424 pid: 3850 ppid:  3849 flags:0x00004002
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 netlink_dump+0x70a/0xdd0 net/netlink/af_netlink.c:2290
 __netlink_dump_start+0x4e4/0x720 net/netlink/af_netlink.c:2398
 netlink_dump_start include/linux/netlink.h:260 [inline]
 rtnetlink_rcv_msg+0xd91/0xf10 net/core/rtnetlink.c:5654
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2073
 __do_sys_sendto net/socket.c:2085 [inline]
 __se_sys_sendto net/socket.c:2081 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f96ce01b407
RSP: 002b:00007fff8c50f300 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f96cdf91740 RCX: 00007f96ce01b407
RDX: 0000000000000014 RSI: 00007fff8c50f390 RDI: 000000000000003e
RBP: 00007fff8c50f374 R08: 00007fff8c50f374 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff8c52fc80
R13: 00007f96cdf916c8 R14: 00007fff8c50f470 R15: 00007fff8c51fa50
 </TASK>
INFO: task kworker/1:4:4274 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D stack:24816 pid: 4274 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4120
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/0:14:4339 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:14    state:D stack:26064 pid: 4339 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4120
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/0:17:4349 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:17    state:D stack:25344 pid: 4349 ppid:     2 flags:0x00004000
Workqueue: events nsim_dev_trap_report_work
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 nsim_dev_trap_report_work+0x56/0xab0 drivers/net/netdevsim/dev.c:757
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/u4:5:4361 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5    state:D stack:24688 pid: 4361 ppid:     2 flags:0x00004000
Workqueue: events_unbound linkwatch_event
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 linkwatch_event+0xa/0x50 net/core/link_watch.c:251
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz-executor:5475 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22192 pid: 5475 ppid:     1 flags:0x00004004
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 ieee80211_rate_control_ops_get net/mac80211/rate.c:192 [inline]
 rate_control_alloc net/mac80211/rate.c:239 [inline]
 ieee80211_init_rate_ctrl_alg+0x171/0x5e0 net/mac80211/rate.c:983
 ieee80211_register_hw+0x23c6/0x3a60 net/mac80211/main.c:1252
 mac80211_hwsim_new_radio+0x209d/0x4050 drivers/net/wireless/mac80211_hwsim.c:3373
 hwsim_new_radio_nl+0xa7d/0xc50 drivers/net/wireless/mac80211_hwsim.c:3949
 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0xd0b/0xfa0 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2073
 __do_sys_sendto net/socket.c:2085 [inline]
 __se_sys_sendto net/socket.c:2081 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1dcd98e98e
RSP: 002b:00007ffc5b50b558 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555582f16500 RCX: 00007f1dcd98e98e
RDX: 0000000000000024 RSI: 00007f1dce784670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc5b50b5d4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f1dce784670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:5555 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22192 pid: 5555 ppid:     1 flags:0x00004004
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 rtnl_lock net/core/rtnetlink.c:72 [inline]
 rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2073
 __do_sys_sendto net/socket.c:2085 [inline]
 __se_sys_sendto net/socket.c:2081 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4dbcdb098e
RSP: 002b:00007ffcb519f5b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055558f492500 RCX: 00007f4dbcdb098e
RDX: 0000000000000028 RSI: 00007f4dbdba6670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffcb519f634 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f4dbdba6670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:5572 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22736 pid: 5572 ppid:     1 flags:0x00004004
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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 del_device_store+0xd3/0x3a0 drivers/net/netdevsim/bus.c:344
 kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2179 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ffb2380598e
RSP: 002b:00007ffc43360628 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555577c8b500 RCX: 00007ffb2380598e
RDX: 0000000000000001 RSI: 00007ffc433606b0 RDI: 0000000000000005
RBP: 00007ffb238dc8ee R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc433606b0 R14: 00007ffb245fb620 R15: 0000000000000003
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
7 locks held by kworker/u4:3/1173:
 #0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90004817d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d441610 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
 #3: ffffffff8d472b28 (devlink_mutex){+.+.}-{3:3}, at: devlink_pernet_pre_exit+0xa4/0x310 net/core/devlink.c:11534
 #4: ffff88805b90e660 (&nsim_bus_dev->nsim_bus_reload_lock){+.+.}-{3:3}, at: nsim_dev_reload_down+0x57/0x160 drivers/net/netdevsim/dev.c:870
 #5: ffff88805b90d400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1359 [inline]
 #5: ffff88805b90d400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_reload_destroy+0x109/0x230 drivers/net/netdevsim/dev.c:1561
 #6: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x8dd/0xac0 net/core/dev.c:10722
4 locks held by udevd/3557:
 #0: ffff88801f15d790 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
 #1: ffff888059604488 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:112
 #2: ffff88805a030490 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:113
 #3: ffff88802af5e178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
 #3: ffff88802af5e178 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2408
2 locks held by dhcpcd/3850:
 #0: ffff88805a65c690 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: __netlink_dump_start+0xf5/0x720 net/netlink/af_netlink.c:2363
 #1: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0x70a/0xdd0 net/netlink/af_netlink.c:2290
2 locks held by getty/3948:
 #0: ffff88802c375098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002d032e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by kworker/1:4/4274:
 #0: ffff88802b3fb138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000306fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4120
3 locks held by kworker/0:14/4339:
 #0: ffff88802b3fb138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900030efd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4120
3 locks held by kworker/0:17/4349:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000317fd00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88805b90d400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x56/0xab0 drivers/net/netdevsim/dev.c:757
3 locks held by kworker/u4:5/4361:
 #0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900033efd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
3 locks held by kworker/1:12/4410:
 #0: ffff888016c71938 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90003ddfd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x82/0xa90 net/wireless/reg.c:2437
4 locks held by syz-executor/5475:
 #0: ffffffff8d4aa450 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
 #1: ffffffff8d4aa2a8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8d4aa2a8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x161/0xfa0 net/netlink/genetlink.c:790
 #2: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: ieee80211_register_hw+0x239f/0x3a60 net/mac80211/main.c:1251
 #3: ffffffff8c1d4a08 (param_lock){+.+.}-{3:3}, at: ieee80211_rate_control_ops_get net/mac80211/rate.c:192 [inline]
 #3: ffffffff8c1d4a08 (param_lock){+.+.}-{3:3}, at: rate_control_alloc net/mac80211/rate.c:239 [inline]
 #3: ffffffff8c1d4a08 (param_lock){+.+.}-{3:3}, at: ieee80211_init_rate_ctrl_alg+0x171/0x5e0 net/mac80211/rate.c:983
1 lock held by syz-executor/5555:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
4 locks held by syz-executor/5572:
 #0: ffff88807ecc6460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #1: ffff88802bc3fc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
 #2: ffff888147f4a660 (kn->active#359){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288
 #3: ffffffff8cd8a5e8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd3/0x3a0 drivers/net/netdevsim/bus.c:344
6 locks held by syz-executor/5575:
 #0: ffff88807ecc6460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #1: ffff88805b091088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
 #2: ffff888147f4a578 (kn->active#360){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288
 #3: ffffffff8cd8a5e8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: new_device_store+0x14c/0x770 drivers/net/netdevsim/bus.c:295
 #4: ffff88802af5e178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
 #4: ffff88802af5e178 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974
 #5: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: devlink_nl_port_fill+0x346/0x8c0 net/core/devlink.c:995
5 locks held by syz.1.72/5660:
 #0: ffff88801f84bc70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff888077106460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffff88801bd72088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
 #3: ffff888143bde918 (kn->active){++++}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288
 #4: ffffffff8c1d4a08 (param_lock){+.+.}-{3:3}, at: kernel_param_lock kernel/params.c:598 [inline]
 #4: ffffffff8c1d4a08 (param_lock){+.+.}-{3:3}, at: param_attr_store+0xcb/0x300 kernel/params.c:583
1 lock held by syz-executor/5719:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5722:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5725:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5728:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5731:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5734:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5737:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5740:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5743:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5746:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5749:
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 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_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4451 Comm: kworker/u4:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:rcu_lock_acquire+0x1a/0x30 include/linux/rcupdate.h:313
Code: 4c 89 f7 e8 18 26 28 f8 e9 5f ff ff ff 0f 1f 00 e8 5b f2 e2 f7 e8 56 f2 e2 f7 48 c7 c7 60 ef 31 8c 31 f6 31 d2 b9 02 00 00 00 <45> 31 c0 45 31 c9 68 45 22 96 89 e8 f6 c9 c6 f7 48 83 c4 08 c3 90
RSP: 0018:ffffc90003e3fbd8 EFLAGS: 00000246
RAX: ffffffff8996224a RBX: dffffc0000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c31ef60
RBP: ffff88807dd6bcc0 R08: ffffffff8d8b1eef R09: 1ffffffff1b163dd
R10: dffffc0000000000 R11: fffffbfff1b163de R12: 0000000000000213
R13: ffff888077e5d098 R14: ffff888058940c80 R15: ffff88807dd6bcd0
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efe18187030 CR3: 000000002adaf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/03 06:32 linux-5.15.y 0248c33e835e 57bbd979 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in netdev_run_todo
2026/08/20 07:18 linux-5.15.y 0eb903b5b519 1e72964b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in netdev_run_todo
2026/08/15 05:06 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in netdev_run_todo
* Struck through repros no longer work on HEAD.