INFO: task hung in cleanup_net (8)

Status: auto-obsoleted due to no activity on 2026/10/04 03:52
Subsystems: net
Labels: prio:high
[Documentation on labels]
First crash: 323d, last: 95d
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
99298298 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ INFO: task hung in cleanup_net (8) 2026/05/25 22:26 2026/05/25 22:26 2026/05/25 23:29 c69befb3
▶ ▼ Similar bugs (17)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in cleanup_net (2) net 1 2 2723d 2723d 0/29 closed as invalid on 2019/05/08 13:05
android-6-12 INFO: task hung in cleanup_net 1 3 346d 424d 0/1 auto-obsoleted due to no activity on 2026/01/25 16:18
android-44 INFO: task hung in cleanup_net 1 10 2677d 2719d 0/2 auto-closed as invalid on 2019/10/25 08:38
upstream INFO: task hung in cleanup_net net 1 1 3227d 3215d 3/29 fixed on 2018/01/03 02:35
linux-5.15 INFO: task hung in cleanup_net (2) origin:lts-only 1 syz error 1 266d 266d 0/3 auto-obsoleted due to no activity on 2026/06/08 01:13
linux-4.19 INFO: task hung in cleanup_net 1 1 2342d 2342d 0/1 auto-closed as invalid on 2020/09/08 00:00
linux-4.14 INFO: task hung in cleanup_net 1 syz, C inconclusive 23 1730d 2735d 0/1 upstream: reported C repro on 2019/04/13 10:16
upstream INFO: task hung in cleanup_net (7) net 1 121 402d 819d 0/29 auto-obsoleted due to no activity on 2025/11/10 21:07
upstream INFO: task hung in cleanup_net (3) net 1 1 2657d 2657d 0/29 auto-closed as invalid on 2019/10/25 14:21
linux-5.15 INFO: task hung in cleanup_net 1 1 784d 784d 0/3 auto-obsoleted due to no activity on 2024/11/23 07:55
android-49 INFO: task hung in cleanup_net 1 4 2727d 2734d 0/3 auto-closed as invalid on 2019/10/18 21:44
upstream INFO: task hung in cleanup_net (4) net 1 2 2241d 2246d 0/29 auto-closed as invalid on 2020/11/17 15:39
android-6-12 INFO: task hung in cleanup_net (2) 1 2 212d 229d 0/1 auto-obsoleted due to no activity on 2026/06/09 00:42
android-414 INFO: task hung in cleanup_net 1 syz, C 45 2595d 2738d 0/1 public: reported C repro on 2019/04/11 00:00
android-49 INFO: task hung in cleanup_net (2) 1 1 2511d 2511d 0/3 auto-closed as invalid on 2020/03/23 02:35
upstream INFO: task hung in cleanup_net (6) net 1 1 1195d 1195d 0/29 auto-obsoleted due to no activity on 2023/09/30 00:07
upstream INFO: task hung in cleanup_net (5) net 1 3 1968d 2013d 0/29 auto-closed as invalid on 2021/09/03 11:33

Sample crash report:
INFO: task kworker/u8:6:158 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:6    state:D stack:21128 pid:158   tgid:158   ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
 cleanup_net+0x586/0x810 net/core/net_namespace.c:709
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz-executor:15795 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:20552 pid:15795 tgid:15795 ppid:1      task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
 netdev_run_todo+0x2ff/0x10d0 net/core/dev.c:11711
 nsim_destroy+0x42b/0x800 drivers/net/netdevsim/netdev.c:1203
 __nsim_dev_port_del+0x14e/0x200 drivers/net/netdevsim/dev.c:1547
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1561 [inline]
 nsim_dev_reload_destroy+0x288/0x490 drivers/net/netdevsim/dev.c:1785
 nsim_drv_remove+0x58/0x160 drivers/net/netdevsim/dev.c:1800
 device_remove drivers/base/dd.c:616 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3961
 device_unregister+0x21/0xf0 drivers/base/core.c:4002
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:491 [inline]
 del_device_store+0x2b5/0x370 drivers/net/netdevsim/bus.c:244
 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61e/0xbb0 fs/read_write.c:687
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1b8f7fe68e
RSP: 002b:00007ffcdd62d0a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055556f662500 RCX: 00007f1b8f7fe68e
RDX: 0000000000000001 RSI: 00007ffcdd62d130 RDI: 0000000000000005
RBP: 00007f1b8f8d46f2 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffcdd62d130 R14: 00007f1b905f4620 R15: 0000000000000003
 </TASK>
INFO: task syz-executor:16572 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:18304 pid:16572 tgid:16572 ppid:1      task_flags:0x40054c flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
 netdev_run_todo+0x2ff/0x10d0 net/core/dev.c:11711
 tun_detach drivers/net/tun.c:647 [inline]
 tun_chr_close+0x13f/0x1c0 drivers/net/tun.c:3506
 __fput+0x42a/0xa80 fs/file_table.c:512
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x73a/0x2360 kernel/exit.c:1004
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1147
 get_signal+0x121b/0x12c0 kernel/signal.c:3038
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4600cfe68e
RSP: 002b:00007ffcaee51768 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: 0000000000000054 RBX: 000055559533d500 RCX: 00007f4600cfe68e
RDX: 00000000[ 1248.610949][   T37] RDX: 0000000000000054 RSI: 00007f4601af4670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffcaee517e4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f4601af4670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:16584 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:18312 pid:16584 tgid:16584 ppid:1      task_flags:0x40054c flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
 netdev_run_todo+0x2ff/0x10d0 net/core/dev.c:11711
 tun_detach drivers/net/tun.c:647 [inline]
 tun_chr_close+0x13f/0x1c0 drivers/net/tun.c:3506
 __fput+0x42a/0xa80 fs/file_table.c:512
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x73a/0x2360 kernel/exit.c:1004
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1147
 get_signal+0x121b/0x12c0 kernel/signal.c:3038
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f95636ce68e
RSP: 002b:00007ffc2f8e0658 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: 0000000000000028 RBX: 00005555611ef500 RCX: 00007f95636ce68e
RDX: 0000000000000028 RSI: 00007f95644c4670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc2f8e06d4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f95644c4670 R15: 0000000000000000
 </TASK>
INFO: task syz.5.3260:16783 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.3260      state:D stack:25656 pid:16783 tgid:16779 ppid:12892  task_flags:0x40054c flags:0x00480003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
 netdev_run_todo+0x2ff/0x10d0 net/core/dev.c:11711
 tun_detach drivers/net/tun.c:647 [inline]
 tun_chr_close+0x13f/0x1c0 drivers/net/tun.c:3506
 __fput+0x42a/0xa80 fs/file_table.c:512
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x73a/0x2360 kernel/exit.c:1004
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1147
 get_signal+0x121b/0x12c0 kernel/signal.c:3038
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1cb9d7de59
RSP: 002b:00007f1cb7fb5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f1cba006090 RCX: 00007f1cb9d7de59
RDX: 0000200000000200 RSI: 00000000400454ca RDI: 0000000000000008
RBP: 00007f1cb9e13e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1cba006128 R14: 00007f1cba006090 R15: 00007ffe3788ba18
 </TASK>

Showing all locks held in the system:
5 locks held by ksoftirqd/0/15:
3 locks held by rcuc/0/20:
1 lock held by khungtaskd/37:
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:6/158:
 #0: ffff88801aea0938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88801aea0938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc9000398fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc9000398fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
6 locks held by kworker/u8:12/1352:
2 locks held by getty/5348:
 #0: ffff888028d960a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
4 locks held by syz-executor/5582:
 #0: ffff88802db48358 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #0: ffff88802db48358 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_recvmsg+0xdb/0x540 net/ipv4/tcp.c:2943
 #1: ffffffff8e059220 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #2: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #3: ffff88802db482a0 (slock-AF_INET#2){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock_rt.h:90 [inline]
 #3: ffff88802db482a0 (slock-AF_INET#2){+...}-{3:3}, at: lock_sock_nested+0x7e/0x130 net/core/sock.c:3844
4 locks held by kworker/u9:3/5603:
3 locks held by kworker/0:5/5721:
3 locks held by kworker/0:6/5837:
 #0: ffff88813ff1b938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88813ff1b938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc90005d27c40 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc90005d27c40 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
5 locks held by kworker/u8:15/8137:
4 locks held by kworker/u8:17/9014:
7 locks held by syz-executor/15795:
 #0: ffff888035e6c500 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
 #0: ffff888035e6c500 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff888061428c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff888028ea1f08 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff888028ea1f08 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee26058 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
 #4: ffff888060a44160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
 #4: ffff888060a44160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
 #4: ffff888060a44160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369
 #5: ffff88803b564310 (&devlink->lock_key#4){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1799
 #6: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz.5.3207/16396:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16572:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16584:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16631:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16695:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
8 locks held by kworker/u8:19/16727:
1 lock held by syz-executor/16751:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16760:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz.5.3260/16783:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16791:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16835:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16880:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16915:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16917:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16949:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by syz-executor/16960:
 #0: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
3 locks held by syz-executor/17022:
1 lock held by syz-executor/17054:
 #0: ffffffff8f5b0578 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8f5b0578 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x767/0xc00 net/core/rtnetlink.c:7082
2 locks held by syz-executor/17071:
 #0: ffffffff8f5a19e0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720 net/core/net_namespace.c:575
 #1: ffffffff8f5b0578 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2d5/0x820 net/ipv4/ip_tunnel.c:1149
3 locks held by syz-executor/17095:
1 lock held by modprobe/17097:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 7e 34 70 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 df 9e d9 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167a28 EFLAGS: 00000202
RAX: 1ffffffff33c7f00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85550470 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99e3fd40 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125c4c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc4056beb4c CR3: 00000000384a6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:128 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
 wait_for_lsr+0xc2/0x300 drivers/tty/serial/8250/8250_port.c:1982
 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3229 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3294 [inline]
 serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3379
 console_emit_next_record kernel/printk/printk.c:3163 [inline]
 console_flush_one_record+0x642/0xb50 kernel/printk/printk.c:3269
 legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/06 03:49 upstream f105f3631d51 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in cleanup_net
2026/04/23 01:35 upstream 2a4c0c11c019 b10da5ec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in cleanup_net
2026/03/15 11:44 upstream 267594792a71 ee8d34d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in cleanup_net
2026/01/01 03:40 upstream 9528d5c091c5 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in cleanup_net
2025/11/19 13:57 upstream 8b690556d8fe 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in cleanup_net
2025/11/19 10:42 upstream 8b690556d8fe ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in cleanup_net
2026/05/20 10:11 linux-next 6a50ba100ace 0909d65f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in cleanup_net
* Struck through repros no longer work on HEAD.