syzbot


INFO: task hung in cangw_pernet_exit (2)

Status: upstream: reported on 2026/04/16 19:03
Reported-by: syzbot+f954b2c9821ea248f90f@syzkaller.appspotmail.com
First crash: 20d, last: 10d
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in cangw_pernet_exit 1 1 2118d 2118d 0/1 auto-closed as invalid on 2020/11/15 21:42
upstream INFO: task hung in cangw_pernet_exit net 1 14 2462d 2959d 0/29 closed as invalid on 2019/10/23 07:27
linux-4.19 INFO: task hung in cangw_pernet_exit (2) 1 6 1389d 1624d 0/1 auto-obsoleted due to no activity on 2022/11/15 03:06
upstream INFO: task hung in cangw_pernet_exit (2) can 1 85 1865d 2041d 0/29 auto-closed as invalid on 2021/06/26 13:07
upstream INFO: task hung in cangw_pernet_exit (3) can 1 syz unreliable 290 1591d 1697d 0/29 closed as invalid on 2022/02/08 10:22
linux-5.15 INFO: task hung in cangw_pernet_exit 1 27 672d 715d 0/3 auto-obsoleted due to no activity on 2024/09/11 11:31

Sample crash report:
INFO: task kworker/u4:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:22736 pid:    9 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 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+0xcfc/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x706/0xba0 net/core/net_namespace.c:635
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task dhcpcd:3852 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:25104 pid: 3852 ppid:     1 flags:0x00004202
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 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+0xcfc/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 vlan_ioctl_handler+0xef/0x5d0 net/8021q/vlan.c:581
 sock_ioctl+0x27a/0x710 net/socket.c:1230
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 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: 0033:0x7f896f076378
RSP: 002b:00007ffcfe87a888 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000055edcda1d680 RCX: 00007f896f076378
RDX: 00007ffcfe87a890 RSI: 0000000000008982 RDI: 000000000000000f
RBP: 00007ffcfe87a890 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 000055edcdb8c590 R14: 00007ffcfe88aca0 R15: 000055edcda1d680
 </TASK>
INFO: task syz-executor:4183 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:21136 pid: 4183 ppid:     1 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x680/0x750 kernel/rcu/tree_exp.h:845
 namespace_unlock+0x23f/0x430 fs/namespace.c:1459
 do_umount fs/namespace.c:1683 [inline]
 path_umount+0xf64/0xfd0 fs/namespace.c:1766
 ksys_umount fs/namespace.c:1789 [inline]
 __do_sys_umount fs/namespace.c:1794 [inline]
 __se_sys_umount fs/namespace.c:1792 [inline]
 __x64_sys_umount+0x12d/0x170 fs/namespace.c:1792
 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: 0033:0x7fada3c6d017
RSP: 002b:00007ffdfa217a98 EFLAGS: 00000246
 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007fada3d01120 RCX: 00007fada3c6d017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffdfa217b50
RBP: 00007ffdfa217b50 R08: 00007ffdfa218b50 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdfa218be0
R13: 00007fada3d01120 R14: 000000000006fbe4 R15: 00007ffdfa218c20
 </TASK>
INFO: task kworker/u4:4:4209 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D
 stack:22736 pid: 4209 ppid:     2 flags:0x00004000
Workqueue: events_unbound fsnotify_mark_destroy_workfn

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x2a2/0x450 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __synchronize_srcu+0x2bb/0x350 kernel/rcu/srcutree.c:930
 fsnotify_mark_destroy_workfn+0x106/0x2f0 fs/notify/mark.c:924
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task udevd:4291 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D
 stack:25200 pid: 4291 ppid:  3560 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 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+0xcfc/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:764 [inline]
 uevent_show+0x17a/0x330 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+0x49b/0xd50 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2167 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x759/0xd60 fs/read_write.c:485
 ksys_read+0x152/0x260 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: 0033:0x7f53af737407
RSP: 002b:00007fff9ef4b1f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f53af649880 RCX: 00007f53af737407
RDX: 0000000000001000 RSI: 000055ba968a0a00 RDI: 0000000000000008
RBP: 00007f53af87fff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f53af87fea0 R14: 0000000000000000 R15: 000055ba968abae0
 </TASK>
INFO: task kworker/u4:8:4303 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:8    state:D stack:22680 pid: 4303 ppid:     2 flags:0x00004000
Workqueue: events_unbound fsnotify_connector_destroy_workfn
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x2a2/0x450 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __synchronize_srcu+0x2bb/0x350 kernel/rcu/srcutree.c:930
 fsnotify_connector_destroy_workfn+0x40/0xa0 fs/notify/mark.c:234
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/1:9:4352 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:9     state:D
 stack:22960 pid: 4352 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 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+0xcfc/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+0xca/0x1540 net/ipv6/addrconf.c:4110
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz-executor:4635 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:21136 pid: 4635 ppid:     1 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 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+0xcfc/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845
 namespace_unlock+0x23f/0x430 fs/namespace.c:1459
 do_umount fs/namespace.c:1683 [inline]
 path_umount+0xf64/0xfd0 fs/namespace.c:1766
 ksys_umount fs/namespace.c:1789 [inline]
 __do_sys_umount fs/namespace.c:1794 [inline]
 __se_sys_umount fs/namespace.c:1792 [inline]
 __x64_sys_umount+0x12d/0x170 fs/namespace.c:1792
 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: 0033:0x7ff834b63017
RSP: 002b:00007ffe63cdc848 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007ff834bf7120 RCX: 00007ff834b63017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe63cdc900
RBP: 00007ffe63cdc900 R08: 00007ffe63cdd900 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe63cdd990
R13: 00007ff834bf7120 R14: 000000000006edca R15: 00007ffe63cdd9d0
 </TASK>
INFO: task syz-executor:7855 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:21808 pid: 7855 ppid:     1 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x680/0x750 kernel/rcu/tree_exp.h:845
 wg_socket_reinit+0x1b9/0x350 drivers/net/wireguard/socket.c:434
 wg_socket_init+0x7e1/0xa40 drivers/net/wireguard/socket.c:412
 wg_open+0x24b/0x420 drivers/net/wireguard/device.c:50
 __dev_open+0x2bf/0x430 net/core/dev.c:1550
 __dev_change_flags+0x20d/0x6a0 net/core/dev.c:8879
 dev_change_flags+0x82/0x1a0 net/core/dev.c:8950
 do_setlink+0xcdb/0x3d60 net/core/rtnetlink.c:2784
 __rtnl_newlink net/core/rtnetlink.c:3455 [inline]
 rtnl_newlink+0x1658/0x1a50 net/core/rtnetlink.c:3577
 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5687
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2072
 __do_sys_sendto net/socket.c:2084 [inline]
 __se_sys_sendto net/socket.c:2080 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2080
 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: 0033:0x7f4d8d6f860e
RSP: 002b:00007ffc2ab0fbf8 EFLAGS: 00000246
 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555584f12500 RCX: 00007f4d8d6f860e
RDX: 0000000000000020 RSI: 00007f4d8e4df670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc2ab0fc74 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f4d8e4df670 R15: 0000000000000000
 </TASK>
INFO: task syz.0.1005:8082 blocked for more than 147 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1005      state:D
 stack:26736 pid: 8082 ppid:  4185 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 synchronize_rcu_expedited+0x5c1/0x750 kernel/rcu/tree_exp.h:861
 packet_release+0x976/0xc30 net/packet/af_packet.c:3175
 __sock_release net/socket.c:651 [inline]
 sock_close+0xd5/0x240 net/socket.c:1345
 __fput+0x234/0x930 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f870f8f1dd9
RSP: 002b:00007fff0ff790e8 EFLAGS: 00000246
 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fff0ff791d0 RCX: 00007f870f8f1dd9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000006fb45 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b31220000 R11: 0000000000000246 R12: 00007fff0ff79210
R13: 00007f870fb6afac R14: 000000000006fbbc R15: 00007f870fb6afa0
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
 #0: 
ffff888016dcd938
 (
(wq_completion)netns
){+.+.}-{0:0}
, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: 
ffffc90000ce7d00
 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: 
ffffffff8d431510
 (
pernet_ops_rwsem
){++++}-{3:3}
, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
 #3: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
1 lock held by khungtaskd/27:
 #0: 
ffffffff8c31eb20
 (
rcu_read_lock
){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by dhcpcd/3852:
 #0: 
ffffffff8d425888
 (
vlan_ioctl_mutex
){+.+.}-{3:3}
, at: sock_ioctl+0x25a/0x710 net/socket.c:1228
 #1: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: vlan_ioctl_handler+0xef/0x5d0 net/8021q/vlan.c:581
2 locks held by getty/3946:
 #0: 
ffff88814d0d8098
 (
&tty->ldisc_sem
){++++}-{0:0}
, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: 
ffffc900025e62e8
 (
&ldata->atomic_read_lock
){+.+.}-{3:3}
, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:4/4209:
 #0: 
ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000306fd00 ((reaper_work).work
){+.+.}-{0:0}
, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
4 locks held by udevd/4291:
 #0: ffff88805e96e418 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
 #1: 
ffff888061155088 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3c0 fs/kernfs/file.c:112
 #2: ffff88804ecf8cb8 (
kn->active
#32
){++++}-{0:0}
, at: kernfs_seq_start+0x71/0x3c0 fs/kernfs/file.c:113
 #3: ffff888073c2e220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #3: ffff888073c2e220 (&dev->mutex){....}-{3:3}, at: uevent_show+0x17a/0x330 drivers/base/core.c:2408
2 locks held by kworker/u4:8/4303:
 #0: 
ffff888016c79138
 (
(wq_completion)events_unbound
){+.+.}-{0:0}
, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: 
ffffc90003377d00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
3 locks held by kworker/1:9/4352:
 #0: 
ffff88802b115938
 (
(wq_completion)ipv6_addrconf
){+.+.}-{0:0}
, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000397fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8d43d408 (rtnl_mutex
){+.+.}-{3:3}
, at: addrconf_dad_work+0xca/0x1540 net/ipv6/addrconf.c:4110
1 lock held by syz-executor/4635:
 #0: 
ffffffff8c3235a8
 (
rcu_state.exp_mutex
){+.+.}-{3:3}
, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845
9 locks held by kworker/0:19/4775:
2 locks held by syz-executor/7855:
 #0: 
ffffffff8d43d408
 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
 #1: 
ffff8880213653e8
 (
&wg->device_update_lock
){+.+.}-{3:3}, at: wg_open+0x223/0x420 drivers/net/wireguard/device.c:49
2 locks held by syz.0.1005/8082:
 #0: ffff88805f7da010 (&sb->s_type->i_mutex_key
#11
){+.+.}-{3:3}
, at: inode_lock include/linux/fs.h:787 [inline]
, at: __sock_release net/socket.c:650 [inline]
, at: sock_close+0x90/0x240 net/socket.c:1345
 #1: ffffffff8c3235a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c3235a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
1 lock held by dhcpcd/8119:
 #0: 
ffff8880205ca120
 (
sk_lock-AF_PACKET
){+.+.}-{0:0}
, at: lock_sock include/net/sock.h:1744 [inline]
, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by syz.4.1013/8122:
 #0: 
ffffffff8c3b44c8
 (
lock#4){+.+.}-{3:3}, at: __lru_add_drain_all+0x68/0xac0 mm/swap.c:782
1 lock held by syz-executor/8125:
 #0: ffffffff8d43d408
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8128:
 #0: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8131:
 #0: 
ffffffff8d43d408
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8134:
 #0: 
ffffffff8d43d408 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8137:
 #0: 
ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8140:
 #0: 
ffffffff8d43d408
 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8143:
 #0: 
ffffffff8d43d408
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8147:
 #0: 
ffffffff8d43d408
 (
rtnl_mutex
){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8149:
 #0: ffffffff8d43d408
 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8152:
 #0: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8155:
 #0: 
ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8158:
 #0: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8162:
 #0: 
ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/8164:
 #0: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43d408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684

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

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 04/18/2026
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+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 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: 4775 Comm: kworker/0:19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:error_return+0x0/0x20 arch/x86/entry/entry_64.S:1097
Code: 48 8b 14 25 e8 6f 02 00 89 d0 48 c1 ea 20 0f 30 0f 1f 44 00 00 48 8d 7c 24 08 e8 7b a2 dc ff 48 89 c7 eb 89 90 90 90 90 90 90 <f6> 84 24 88 00 00 00 03 0f 84 72 fd ff ff e9 0d fd ff ff 90 90 90
RSP: 0018:ffffc90002ebe398 EFLAGS: 00000082
RAX: 6ec499ca26c11600 RBX: 0000000000000000 RCX: 6ec499ca26c11600
RDX: dffffc0000000000 RSI: ffffffff8a2b2800 RDI: ffffffff8a79fe40
RBP: 0000000000000000 R08: ffffffff901d51f7 R09: 1ffffffff203aa3e
R10: dffffc0000000000 R11: fffffbfff203aa3f R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb0b1c62000 CR3: 000000002a7d0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
RIP: 0010:console_trylock_spinning+0x301/0x370 kernel/printk/printk.c:1909
Code: 85 db 74 89 e8 f0 e9 18 00 fb 31 c0 eb 48 e8 e6 e9 18 00 e8 01 8f 5c 08 48 85 db 74 d1 e8 d7 e9 18 00 fb 48 c7 c7 60 36 31 8c <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 68 ba 4a 60
RSP: 0018:ffffc90002ebe440 EFLAGS: 00000246
RAX: ffffffff81604ab9 RBX: 0000000000000200 RCX: 0000000000100000
RDX: ffffc90013559000 RSI: 00000000000fffff RDI: ffffffff8c313660
RBP: ffffc90002ebe510 R08: ffffffff901d51f7 R09: 1ffffffff203aa3e
R10: dffffc0000000000 R11: fffffbfff203aa3f R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff920005d7c88
 vprintk_emit+0xa7/0x150 kernel/printk/printk.c:2273
 dev_vprintk_emit+0x2e1/0x380 drivers/base/core.c:4638
 dev_printk_emit+0xeb/0x140 drivers/base/core.c:4649
 _dev_err+0x11b/0x170 drivers/base/core.c:4704
 parse_uac2_sample_rate_range+0x992/0xc60 sound/usb/format.c:401
 parse_audio_format_rates_v2v3+0x3c7/0x16c0 sound/usb/format.c:636
 parse_audio_format_ii sound/usb/format.c:778 [inline]
 snd_usb_parse_audio_format+0x4ae/0x740 sound/usb/format.c:799
 snd_usb_get_audioformat_uac12 sound/usb/stream.c:854 [inline]
 __snd_usb_parse_audio_interface+0x18b1/0x4b00 sound/usb/stream.c:1196
 snd_usb_parse_audio_interface+0x36/0xb0 sound/usb/stream.c:1274
 create_standard_audio_quirk+0x59/0x120 sound/usb/quirks.c:100
 snd_usb_create_quirk sound/usb/quirks.c:577 [inline]
 create_composite_quirk+0x1ec/0x4e0 sound/usb/quirks.c:48
 usb_audio_probe+0xb97/0x1d90 sound/usb/card.c:885
 usb_probe_interface+0x5c5/0xb20 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a8/0x480 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 usb_set_configuration+0x1991/0x1fd0 drivers/usb/core/message.c:2223
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x139/0x270 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a8/0x480 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 usb_new_device+0xd65/0x1660 drivers/usb/core/hub.c:2632
 hub_port_connect drivers/usb/core/hub.c:5497 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
 port_event drivers/usb/core/hub.c:5799 [inline]
 hub_event+0x2e4a/0x55e0 drivers/usb/core/hub.c:5881
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/27 00:44 linux-5.15.y b9d57c40a767 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/04/16 19:02 linux-5.15.y 91d48252ad4b 4743f87d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
* Struck through repros no longer work on HEAD.