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INFO: task hung in linkwatch_event (3)

Status: upstream: reported on 2025/09/20 20:03
Reported-by: syzbot+42d5561bdaee9b3a7582@syzkaller.appspotmail.com
First crash: 14h06m, last: 14h06m
▶ ▼ Similar bugs (19)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in linkwatch_event (2) 1 1 224d 224d 0/3 auto-obsoleted due to no activity on 2025/05/19 15:08
linux-6.1 INFO: task hung in linkwatch_event (4) 1 syz 7 100d 192d 0/3 auto-obsoleted due to no activity on 2025/09/20 14:43
android-414 INFO: task hung in linkwatch_event 1 C 7 2135d 2355d 0/1 public: reported C repro on 2019/04/10 16:14
linux-6.6 INFO: task hung in linkwatch_event 1 3 21d 78d 0/2 upstream: reported on 2025/07/04 13:16
linux-4.14 INFO: task hung in linkwatch_event (2) 1 1 1156d 1156d 0/1 auto-obsoleted due to no activity on 2022/11/19 11:58
android-44 INFO: task hung in linkwatch_event 1 6 2571d 2717d 0/2 auto-closed as invalid on 2019/03/05 13:11
linux-5.15 INFO: task hung in linkwatch_event 1 84 323d 618d 0/3 auto-obsoleted due to no activity on 2025/01/11 00:55
upstream INFO: task hung in linkwatch_event (4) net 1 C done 3350 1d06h 421d 0/29 upstream: reported C repro on 2024/07/27 06:21
upstream INFO: task hung in linkwatch_event net 1 C 82 2164d 2775d 0/29 closed as dup on 2018/02/14 15:33
linux-4.14 INFO: task hung in linkwatch_event 1 5 1840d 1967d 0/1 auto-closed as invalid on 2021/01/05 01:42
linux-4.19 INFO: task hung in linkwatch_event (2) 1 C error 217 931d 2019d 0/1 upstream: reported C repro on 2020/03/11 20:12
upstream INFO: task hung in linkwatch_event (2) net 1 C done done 1033 1245d 1971d 20/29 fixed on 2022/05/13 11:13
linux-4.19 INFO: task hung in linkwatch_event 1 3 2173d 2287d 0/1 auto-closed as invalid on 2020/02/07 01:11
upstream INFO: task hung in linkwatch_event (3) net 1 1634 439d 1033d 26/29 fixed on 2024/07/09 19:14
linux-4.14 INFO: task hung in linkwatch_event (3) 1 2 991d 991d 0/1 upstream: reported on 2023/01/03 10:49
android-49 INFO: task hung in linkwatch_event 1 13 2335d 2352d 0/3 auto-closed as invalid on 2019/10/25 08:50
linux-6.1 INFO: task hung in linkwatch_event (2) 1 32 374d 488d 0/3 auto-obsoleted due to no activity on 2024/11/21 00:32
linux-6.1 INFO: task hung in linkwatch_event 1 2 777d 893d 0/3 auto-obsoleted due to no activity on 2023/11/14 00:59
linux-6.1 INFO: task hung in linkwatch_event (3) 1 1 299d 299d 0/3 auto-obsoleted due to no activity on 2025/03/05 15:51

Sample crash report:
INFO: task kworker/u4:4:1245 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:21280 pid: 1245 ppid:     2 flags:0x00004000
Workqueue: events_unbound linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 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+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 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/1:7:4706 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:7     state:D stack:24832 pid: 4706 ppid:     2 flags:0x00004000
Workqueue: events switchdev_deferred_process_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 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.1.3550:16612 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.3550      state:D stack:27424 pid:16612 ppid: 16171 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 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+0x974/0xe60 net/core/rtnetlink.c:5647
 netlink_rcv_skb+0x1e0/0x430 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+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg+0x190/0x250 net/socket.c:2526
 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: 0033:0x7f483fc93c29
RSP: 002b:00007f483deda038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f483fedb090 RCX: 00007f483fc93c29
RDX: 0000000000040000 RSI: 0000200000000040 RDI: 0000000000000007
RBP: 00007f483fd16e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f483fedb128 R14: 00007f483fedb090 R15: 00007ffeea0aea68
 </TASK>
INFO: task syz.8.3551:16605 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.3551      state:D stack:27008 pid:16605 ppid: 16210 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 tun_detach drivers/net/tun.c:699 [inline]
 tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3440
 __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: 0033:0x7f7573a54c29
RSP: 002b:00007fff26c64b88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f7573c9dda0 RCX: 00007f7573a54c29
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f7573c9dda0 R08: 0000000000000224 R09: 0000001e26c64e7f
R10: 00007f7573c9dcb0 R11: 0000000000000246 R12: 0000000000086167
R13: 00007f7573c9c270 R14: ffffffffffffffff R15: 00007fff26c64ca0
 </TASK>
INFO: task syz.8.3551:16607 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.3551      state:D stack:28320 pid:16607 ppid: 16210 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 wext_ioctl_dispatch+0xaf/0x470 net/wireless/wext-core.c:996
 wext_handle_ioctl+0x104/0x1c0 net/wireless/wext-core.c:1058
 sock_ioctl+0x145/0x6e0 net/socket.c:1191
 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: 0033:0x7f7573a54c29
RSP: 002b:00007f7571cbc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7573c9bfa0 RCX: 00007f7573a54c29
RDX: 0000200000000040 RSI: 0000000000008b04 RDI: 0000000000000005
RBP: 00007f7573ad7e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7573c9c038 R14: 00007f7573c9bfa0 R15: 00007fff26c64a28
 </TASK>
INFO: task syz.8.3551:16613 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.3551      state:D stack:27872 pid:16613 ppid: 16210 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 __tun_chr_ioctl+0x3ab/0x1e70 drivers/net/tun.c:3052
 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: 0033:0x7f7573a54c29
RSP: 002b:00007f7571c9b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7573c9c090 RCX: 00007f7573a54c29
RDX: 0000000000000000 RSI: 00000000400454c8 RDI: 0000000000000008
RBP: 00007f7573ad7e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7573c9c128 R14: 00007f7573c9c090 R15: 00007fff26c64a28
 </TASK>
INFO: task syz.7.3554:16619 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.3554      state:D stack:24384 pid:16619 ppid: 15779 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 tun_detach drivers/net/tun.c:699 [inline]
 tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3440
 __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: 0033:0x7f8717f31c29
RSP: 002b:00007f8716199038 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f8718178fa0 RCX: 00007f8717f31c29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009
RBP: 00007f8717fb4e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8718179038 R14: 00007f8718178fa0 R15: 00007fff4adb9f98
 </TASK>
INFO: task syz.7.3554:16626 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.3554      state:D stack:27008 pid:16626 ppid: 15779 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 ppp_create_interface drivers/net/ppp/ppp_generic.c:3359 [inline]
 ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1069 [inline]
 ppp_ioctl+0x64f/0x1960 drivers/net/ppp/ppp_generic.c:742
 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: 0033:0x7f8717f31c29
RSP: 002b:00007f8716178038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8718179090 RCX: 00007f8717f31c29
RDX: 000000110e22fff6 RSI: 00000000c004743e RDI: 000000000000000a
RBP: 00007f8717fb4e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8718179128 R14: 00007f8718179090 R15: 00007fff4adb9f98
 </TASK>
INFO: task syz.0.3555:16620 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.3555      state:D stack:27520 pid:16620 ppid: 16209 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 ip6mr_sk_done+0xaa/0x2b0 net/ipv6/ip6mr.c:1584
 rawv6_close+0x62/0x90 net/ipv6/raw.c:1206
 inet_release+0x139/0x180 net/ipv4/af_inet.c:432
 __sock_release net/socket.c:649 [inline]
 sock_close+0xd5/0x240 net/socket.c:1336
 __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: 0033:0x7fc6feec3c29
RSP: 002b:00007ffd777cad38 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fc6ff10cda0 RCX: 00007fc6feec3c29
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fc6ff10cda0 R08: 0000000000000000 R09: 00000006777cb02f
R10: 000000000003fda0 R11: 0000000000000246 R12: 0000000000086375
R13: 00007fc6ff10b180 R14: ffffffffffffffff R15: 0000000000000003
 </TASK>
INFO: task syz.6.3558:16632 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.3558      state:D stack:26752 pid:16632 ppid: 16201 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0xc71/0x2390 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+0x974/0xe60 net/core/rtnetlink.c:5647
 netlink_rcv_skb+0x1e0/0x430 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+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg+0x190/0x250 net/socket.c:2526
 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: 0033:0x7f756ed8cc29
RSP: 002b:00007f756cff4038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f756efd3fa0 RCX: 00007f756ed8cc29
RDX: 0000000000000000 RSI: 0000200000000940 RDI: 0000000000000004
RBP: 00007f756ee0fe41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f756efd4038 R14: 00007f756efd3fa0 R15: 00007fff3b723db8
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:1/13:
 #0: ffff88802a74a938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90000d27d00 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4654
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:4/1245:
 #0: ffff888016879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900051a7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
2 locks held by getty/3946:
 #0: ffff88802aad0098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:5/4266:
5 locks held by kworker/u4:8/4501:
3 locks held by kworker/1:7/4706:
 #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000377fd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74
3 locks held by kworker/1:11/16379:
 #0: ffff888016871938 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000326fd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x81/0xa50 net/wireless/reg.c:2437
1 lock held by syz.1.3550/16612:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz.8.3551/16605:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3440
1 lock held by syz.8.3551/16607:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: wext_ioctl_dispatch+0xaf/0x470 net/wireless/wext-core.c:996
1 lock held by syz.8.3551/16613:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3ab/0x1e70 drivers/net/tun.c:3052
1 lock held by syz.7.3554/16619:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3440
2 locks held by syz.7.3554/16626:
 #0: ffffffff8cac7388 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xca/0x1960 drivers/net/ppp/ppp_generic.c:738
 #1: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: ppp_create_interface drivers/net/ppp/ppp_generic.c:3359 [inline]
 #1: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1069 [inline]
 #1: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x64f/0x1960 drivers/net/ppp/ppp_generic.c:742
2 locks held by syz.0.3555/16620:
 #0: ffff888058da8210 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #0: ffff888058da8210 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline]
 #0: ffff888058da8210 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1336
 #1: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: ip6mr_sk_done+0xaa/0x2b0 net/ipv6/ip6mr.c:1584
1 lock held by syz.6.3558/16632:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16636:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16640:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16646:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16648:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16650:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16654:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16658:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16663:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16665:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16667:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16671:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16672:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16681:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16683:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
1 lock held by syz-executor/16685:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4266 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:752 [inline]
RIP: 0010:batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline]
RIP: 0010:batadv_iv_ogm_schedule+0x40d/0xe90 net/batman-adv/bat_iv_ogm.c:868
Code: 80 0c 00 00 31 db 4c 89 e0 48 c1 e8 03 48 89 84 24 88 00 00 00 4c 89 a4 24 90 00 00 00 48 8b 84 24 88 00 00 00 42 80 3c 38 00 <74> 08 4c 89 e7 e8 d9 6e 42 f8 48 89 5c 24 40 48 8d 1c dd 00 00 00
RSP: 0018:ffffc900032bfa40 EFLAGS: 00000246
RAX: 1ffff110054efca8 RBX: 000000000000032e RCX: ffff88802885d940
RDX: 0000000000000000 RSI: ffffffff8a0b2ac0 RDI: ffffffff8a59a480
RBP: ffffc900032bfb80 R08: dffffc0000000000 R09: fffffbfff1ad323e
R10: fffffbfff1ad323e R11: 1ffffffff1ad323d R12: ffff88802a77e540
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564756b61650 CR3: 000000007e616000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 batadv_iv_send_outstanding_bat_ogm_packet+0x72d/0x840 net/batman-adv/bat_iv_ogm.c:1712
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 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 (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/20 20:03 linux-5.15.y 43bb85222e53 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in linkwatch_event
* Struck through repros no longer work on HEAD.