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INFO: task hung in switchdev_deferred_process_work (5)

Status: upstream: reported on 2026/05/27 14:28
Reported-by: syzbot+14c75832211f88b35d25@syzkaller.appspotmail.com
First crash: 3h01m, last: 3h01m
▶ ▼ Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: task hung in switchdev_deferred_process_work (2) 1 10 7d10h 176d 0/2 upstream: reported on 2025/12/02 15:22
linux-6.1 INFO: task hung in switchdev_deferred_process_work (2) 1 1 247d 247d 0/3 auto-obsoleted due to no activity on 2025/12/31 08:30
linux-6.1 INFO: task hung in switchdev_deferred_process_work (3) 1 1 7d01h 7d01h 0/3 upstream: reported on 2026/05/20 16:07
upstream INFO: task hung in switchdev_deferred_process_work (2) net 1 C inconclusive 1226 687d 2130d 26/29 fixed on 2024/07/09 19:14
linux-6.6 INFO: task hung in switchdev_deferred_process_work 1 1 308d 308d 0/2 auto-obsoleted due to no activity on 2025/10/31 04:22
upstream INFO: task hung in switchdev_deferred_process_work net 1 35 2420d 2956d 0/29 closed as invalid on 2019/10/23 07:26
upstream INFO: task hung in switchdev_deferred_process_work (3) net 1 C inconclusive 634 1d15h 656d 0/29 upstream: reported C repro on 2024/08/08 21:14
linux-5.15 INFO: task hung in switchdev_deferred_process_work (4) 1 2 159d 167d 0/3 auto-obsoleted due to no activity on 2026/03/29 12:57
linux-5.15 INFO: task hung in switchdev_deferred_process_work 1 1 1141d 1141d 0/3 auto-obsoleted due to no activity on 2023/08/10 05:46
linux-4.19 INFO: task hung in switchdev_deferred_process_work 1 95 1193d 2271d 0/1 upstream: reported on 2020/03/08 04:06
linux-4.14 INFO: task hung in switchdev_deferred_process_work 1 1 1482d 1482d 0/1 auto-obsoleted due to no activity on 2022/09/03 16:45
linux-5.15 INFO: task hung in switchdev_deferred_process_work (2) 1 36 795d 866d 0/3 auto-obsoleted due to no activity on 2024/06/01 16:21
linux-5.15 INFO: task hung in switchdev_deferred_process_work (3) 1 8 579d 722d 0/3 auto-obsoleted due to no activity on 2025/02/02 03:46
linux-6.1 INFO: task hung in switchdev_deferred_process_work 1 8 686d 849d 0/3 auto-obsoleted due to no activity on 2024/10/18 09:59

Sample crash report:
INFO: task kworker/1:1:23 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:1     state:D stack:21816 pid:   23 ppid:     2 flags:0x00004000
Workqueue: events switchdev_deferred_process_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
 switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74
 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 khugepaged:33 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:khugepaged      state:D stack:26992 pid:   33 ppid:     2 flags:0x00004000
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
 __flush_work+0x15a/0x210 kernel/workqueue.c:3094
 __lru_add_drain_all+0x9ce/0xac0 mm/swap.c:833
 khugepaged_do_scan mm/khugepaged.c:2276 [inline]
 khugepaged+0x13a/0x11f0 mm/khugepaged.c:2337
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/u4:15:5016 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:15   state:D stack:21880 pid: 5016 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 kworker/1:0:15358 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0     state:D stack:23288 pid:15358 ppid:     2 flags:0x00004000
Workqueue: events key_garbage_collector
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
 synchronize_rcu+0x119/0x1e0 kernel/rcu/tree.c:3802
 key_garbage_collector+0x8f6/0xa70 security/keys/gc.c:303
 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:27254 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:28368 pid:27254 ppid:  3854 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
 synchronize_rcu_expedited+0x5c1/0x750 kernel/rcu/tree_exp.h:861
 synchronize_rcu+0x119/0x1e0 kernel/rcu/tree.c:3802
 __unregister_prot_hook+0x3f7/0x570 net/packet/af_packet.c:347
 packet_do_bind+0x50a/0xda0 net/packet/af_packet.c:3253
 __sys_bind+0x2e9/0x3e0 net/socket.c:1729
 __do_sys_bind net/socket.c:1740 [inline]
 __se_sys_bind net/socket.c:1738 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1738
 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: 0033:0x7fd1308b02d7
RSP: 002b:00007ffe4bbf61b8 EFLAGS: 00000213 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00005586d14e7d10 RCX: 00007fd1308b02d7
RDX: 0000000000000014 RSI: 00007ffe4bbf61d0 RDI: 0000000000000003
RBP: 00005586a18294b0 R08: 00007fd13097fac0 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000213 R12: 0000000000000000
R13: 00005586d14eb400 R14: 0000000000000000 R15: 00005586a183eac0
 </TASK>
INFO: task syz.6.5998:27260 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.5998      state:D stack:26032 pid:27260 ppid:  5862 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
 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
 drop_collected_mounts fs/namespace.c:1948 [inline]
 put_mnt_ns+0xdb/0x120 fs/namespace.c:4426
 free_nsproxy+0x49/0x3c0 kernel/nsproxy.c:191
 do_exit+0x621/0x20c0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:998
 get_signal+0x6d6/0x12d0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 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: 0033:0x7f2815078e59
RSP: 002b:00007f28132b10e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f28152f2098 RCX: 00007f2815078e59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f28152f2098
RBP: 00007f28152f2090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f28152f2128 R14: 00007ffeef9c2110 R15: 00007ffeef9c21f8
 </TASK>
INFO: task syz.8.5999:27261 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.5999      state:D stack:21552 pid:27261 ppid: 19715 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
 synchronize_rcu+0x119/0x1e0 kernel/rcu/tree.c:3802
 caif_disconnect_client+0x146/0x1e0 net/caif/cfcnfg.c:197
 chnl_net_open+0x6d7/0xa00 net/caif/chnl_net.c:326
 __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_group_changelink net/core/rtnetlink.c:3301 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3465 [inline]
 rtnl_newlink+0xf8d/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_sendmsg+0x5b7/0x8f0 net/socket.c:2445
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499
 __sys_sendmsg net/socket.c:2528 [inline]
 __do_sys_sendmsg net/socket.c:2537 [inline]
 __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535
 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: 0033:0x7fe522c3be59
RSP: 002b:00007fe520e95028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe522eb4fa0 RCX: 00007fe522c3be59
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fe522cd1d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe522eb5038 R14: 00007fe522eb4fa0 R15: 00007ffc63c5e5e8
 </TASK>
INFO: task syz.2.6000:27268 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.6000      state:D stack:26608 pid:27268 ppid:  4200 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
 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
 drop_collected_mounts fs/namespace.c:1948 [inline]
 put_mnt_ns+0xdb/0x120 fs/namespace.c:4426
 free_nsproxy+0x49/0x3c0 kernel/nsproxy.c:191
 do_exit+0x621/0x20c0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:998
 get_signal+0x6d6/0x12d0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 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: 0033:0x7fd681135e59
RSP: 002b:00007fd67f34d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fd6813af188 RCX: 00007fd681135e59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd6813af188
RBP: 00007fd6813af180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd6813af218 R14: 00007ffd156eb1f0 R15: 00007ffd156eb2d8
 </TASK>
INFO: task syz.7.6001:27270 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.6001      state:D stack:27344 pid:27270 ppid:  6488 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
 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
 drop_collected_mounts fs/namespace.c:1948 [inline]
 put_mnt_ns+0xdb/0x120 fs/namespace.c:4426
 free_nsproxy+0x49/0x3c0 kernel/nsproxy.c:191
 do_exit+0x621/0x20c0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:998
 get_signal+0x6d6/0x12d0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 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: 0033:0x7f1093287e59
RSP: 002b:00007f109149f0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f1093501188 RCX: 00007f1093287e59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1093501188
RBP: 00007f1093501180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1093501218 R14: 00007ffc2e9aa5b0 R15: 00007ffc2e9aa698
 </TASK>
INFO: task dhcpcd:27271 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:26800 pid:27271 ppid:  3854 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
 exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
 synchronize_rcu_expedited+0x680/0x750 kernel/rcu/tree_exp.h:845
 __unregister_prot_hook+0x3f7/0x570 net/packet/af_packet.c:347
 packet_do_bind+0x50a/0xda0 net/packet/af_packet.c:3253
 __sys_bind+0x2e9/0x3e0 net/socket.c:1729
 __do_sys_bind net/socket.c:1740 [inline]
 __se_sys_bind net/socket.c:1738 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1738
 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: 0033:0x7fd1308b02d7
RSP: 002b:00007ffe4bbf61b8 EFLAGS: 00000213 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00005586d14e7d10 RCX: 00007fd1308b02d7
RDX: 0000000000000014 RSI: 00007ffe4bbf61d0 RDI: 0000000000000003
RBP: 00005586a18294b0 R08: 00007fd13097fac0 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000213 R12: 0000000000000000
R13: 00005586d14eb5d0 R14: 0000000000000000 R15: 00005586a183eac0
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/1:1/23:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc90000ddfd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74
1 lock held by khungtaskd/27:
 #0: ffffffff8c31f320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by khugepaged/33:
 #0: ffffffff8c3b4cc8 (lock#4){+.+.}-{3:3}, at: __lru_add_drain_all+0x68/0xac0 mm/swap.c:782
2 locks held by getty/3947:
 #0: ffff88814c877098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900028832e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:15/5016:
 #0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900036afd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8d431cd0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
 #3: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
2 locks held by kworker/1:0/15358:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900040ffd00 (key_gc_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
4 locks held by kworker/0:5/20685:
2 locks held by dhcpcd/27254:
 #0: ffff88801eec4120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88801eec4120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
 #1: ffffffff8c323da8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c323da8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
2 locks held by syz.8.5999/27261:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
 #1: ffffffff8c323da8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #1: ffffffff8c323da8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845
1 lock held by dhcpcd/27271:
 #0: ffff888030cbc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888030cbc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27272:
 #0: ffff88807da7a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807da7a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27273:
 #0: ffff888044dbe120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888044dbe120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27274:
 #0: ffff88804c224120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88804c224120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27275:
 #0: ffff888069a54120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888069a54120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27276:
 #0: ffff888069332120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888069332120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by syz-executor/27278:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27284:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27285:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27292:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27294:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by dhcpcd/27296:
 #0: ffff88807d1ba120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807d1ba120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27297:
 #0: ffff88807a7a6120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807a7a6120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27298:
 #0: ffff88807e6bc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807e6bc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27299:
 #0: ffff888063fbc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888063fbc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27300:
 #0: ffff88807bd12120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807bd12120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27301:
 #0: ffff88802b17e120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88802b17e120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27302:
 #0: ffff888050074120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888050074120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27303:
 #0: ffff88804075a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88804075a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27304:
 #0: ffff88804cc40120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88804cc40120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27305:
 #0: ffff888074d56120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888074d56120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27306:
 #0: ffff88804c984120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88804c984120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27307:
 #0: ffff888068f06120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888068f06120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27308:
 #0: ffff888065524120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888065524120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27309:
 #0: ffff88807d98e120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807d98e120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27310:
 #0: ffff888077818120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888077818120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27311:
 #0: ffff88804dcfc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88804dcfc120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27312:
 #0: ffff88801dcbe120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88801dcbe120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27313:
 #0: ffff88805bd0a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88805bd0a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27314:
 #0: ffff88807b400120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88807b400120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by dhcpcd/27315:
 #0: ffff888073c74120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888073c74120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3213
1 lock held by syz-executor/27317:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27323:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27328:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27329:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27332:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27335:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27340:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27345:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27347:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5684
1 lock held by syz-executor/27349:
 #0: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43dbc8 (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: 22093 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_acquire+0x3d7/0x7d10 kernel/locking/lockdep.c:4947
Code: 64 24 78 49 8d 7c 24 08 48 89 f8 48 c1 e8 03 42 80 3c 00 00 74 0f e8 48 3a 61 00 49 b8 00 00 00 00 00 fc ff df 48 8b 44 24 78 <4c> 89 78 08 49 89 c7 48 8d 78 10 48 89 f8 48 c1 e8 03 42 80 3c 00
RSP: 0018:ffffc9000371f7c0 EFLAGS: 00000046
RAX: ffff88802d6fc6c0 RBX: ffffffff8c31f320 RCX: 1ffff11005adf8dc
RDX: 0000000000000015 RSI: 0000000000000000 RDI: ffff88802d6fc6c8
RBP: ffffc9000371fa10 R08: dffffc0000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1b13f06 R12: ffff88802d6fc6c0
R13: 0000000000000000 R14: 0000000000000015 R15: ffffffff8991d475
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffc0e68f2c CR3: 000000002b41f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 batadv_nc_process_nc_paths+0xb2/0x350 net/batman-adv/network-coding.c:691
 batadv_nc_worker+0x3e5/0x5c0 net/batman-adv/network-coding.c:732
 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 (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/27 14:28 linux-5.15.y 241d66fa280c 8777bdc3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in switchdev_deferred_process_work
* Struck through repros no longer work on HEAD.