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:21080 pid: 9 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: 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 kthread_stop+0x16e/0x540 kernel/kthread.c:666 destroy_workqueue+0xf2/0xb20 kernel/workqueue.c:4451 wg_destruct+0x1e8/0x300 drivers/net/wireguard/device.c:241 netdev_run_todo+0x851/0xa70 net/core/dev.c:10717 default_device_exit_batch+0x369/0x3c0 net/core/dev.c:11694 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x791/0xba0 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 INFO: task wg-crypt-wg2:4953 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:wg-crypt-wg2 state:D stack:29872 pid: 4953 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 percpu_rwsem_wait+0x2e6/0x320 kernel/locking/percpu-rwsem.c:160 __percpu_down_read+0xc9/0x100 kernel/locking/percpu-rwsem.c:174 percpu_down_read include/linux/percpu-rwsem.h:65 [inline] cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:724 [inline] exit_signals+0x3e5/0x510 kernel/signal.c:2991 do_exit+0x25e/0x20c0 kernel/exit.c:831 kthread_exit+0x11/0x20 kernel/kthread.c:283 kthread+0x454/0x520 kernel/kthread.c:336 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 INFO: task syz-executor:5028 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:21840 pid: 5028 ppid: 5025 flags:0x00004000 Call Trace: 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 cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1662 __cgroup_procs_write+0x73/0x350 kernel/cgroup/cgroup.c:5013 cgroup_procs_write+0x23/0x40 kernel/cgroup/cgroup.c:5053 cgroup_file_write+0x2c3/0x660 kernel/cgroup/cgroup.c:3967 kernfs_fop_write_iter+0x379/0x4c0 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x745/0xd60 fs/read_write.c:594 ksys_write+0x152/0x260 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f28383b4e0e RSP: 002b:00007ffe1de962e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000555557f36500 RCX: 00007f28383b4e0e RDX: 0000000000000001 RSI: 00007ffe1de96370 RDI: 0000000000000003 RBP: 00007ffe1de968e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffe1de96370 R14: 00007ffe1de968a0 R15: 00007ffe1de968e0 INFO: task syz-executor:5031 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21968 pid: 5031 ppid: 5026 flags:0x00004000 Call Trace: 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 cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1662 __cgroup_procs_write+0x73/0x350 kernel/cgroup/cgroup.c:5013 cgroup_procs_write+0x23/0x40 kernel/cgroup/cgroup.c:5053 cgroup_file_write+0x2c3/0x660 kernel/cgroup/cgroup.c:3967 kernfs_fop_write_iter+0x379/0x4c0 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x745/0xd60 fs/read_write.c:594 ksys_write+0x152/0x260 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f51b091ee0e RSP: 002b:00007ffe929c11d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055555dca6500 RCX: 00007f51b091ee0e RDX: 0000000000000001 RSI: 00007ffe929c1260 RDI: 0000000000000003 RBP: 00007ffe929c17d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffe929c1260 R14: 00007ffe929c1790 R15: 00007ffe929c17d0 INFO: task syz-executor:5039 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20152 pid: 5039 ppid: 5030 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165 mmap_write_lock include/linux/mmap_lock.h:71 [inline] mpol_rebind_mm+0x33/0x2c0 mm/mempolicy.c:381 cpuset_attach+0x336/0x620 kernel/cgroup/cpuset.c:2376 cgroup_migrate_execute+0x7eb/0x1010 kernel/cgroup/cgroup.c:2598 cgroup_attach_task+0x53e/0x7b0 kernel/cgroup/cgroup.c:2893 __cgroup1_procs_write+0x2ee/0x3f0 kernel/cgroup/cgroup-v1.c:527 cgroup_file_write+0x2c3/0x660 kernel/cgroup/cgroup.c:3967 kernfs_fop_write_iter+0x379/0x4c0 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x745/0xd60 fs/read_write.c:594 ksys_write+0x152/0x260 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f4d31f2de0e RSP: 002b:00007ffee3f0b0f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055556c32b500 RCX: 00007f4d31f2de0e RDX: 0000000000000001 RSI: 00007ffee3f0b180 RDI: 0000000000000003 RBP: 00007ffee3f0b6f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffee3f0b180 R14: 00007ffee3f0b6b0 R15: 00007ffee3f0b6f0 INFO: task udevd:5274 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:26768 pid: 5274 ppid: 3561 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 percpu_rwsem_wait+0x2e6/0x320 kernel/locking/percpu-rwsem.c:160 __percpu_down_read+0xc9/0x100 kernel/locking/percpu-rwsem.c:174 percpu_down_read include/linux/percpu-rwsem.h:65 [inline] cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:724 [inline] exit_signals+0x3e5/0x510 kernel/signal.c:2991 do_exit+0x25e/0x20c0 kernel/exit.c:831 do_group_exit+0x12e/0x300 kernel/exit.c:998 __do_sys_exit_group kernel/exit.c:1009 [inline] __se_sys_exit_group kernel/exit.c:1007 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1007 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: 0033:0x7fc782bc26c5 RSP: 002b:00007fff61766df8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000056541778e220 RCX: 00007fc782bc26c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 0000565417786910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff61766e40 R14: 0000000000000000 R15: 0000000000000000 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: ffffffff8d432590 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589 #3: ffff8880738313e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_destruct+0x112/0x300 drivers/net/wireguard/device.c:233 1 lock held by khungtaskd/27: #0: ffffffff8c31f360 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 3 locks held by kworker/u4:4/1279: 2 locks held by getty/3952: #0: ffff88802c7d7098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158 1 lock held by wg-crypt-wg2/4953: #0: ffffffff8c344e30 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x25e/0x20c0 kernel/exit.c:831 3 locks held by syz-executor/5028: #0: ffff88801db5c460 (sb_writers#10){.+.+}-{0:0}, at: vfs_write+0x295/0xd60 fs/read_write.c:590 #1: ffff8880726a7488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffffffff8c344c48 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1662 3 locks held by syz-executor/5031: #0: ffff88801db5c460 (sb_writers#10){.+.+}-{0:0}, at: vfs_write+0x295/0xd60 fs/read_write.c:590 #1: ffff888071fc0888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffffffff8c344c48 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1662 1 lock held by syz-executor/5032: #0: ffffffff8c344e30 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x25e/0x20c0 kernel/exit.c:831 2 locks held by syz-executor/5035: #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline] #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline] #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x22c/0x13f0 kernel/fork.c:1518 #1: ffff88802c2d7828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #1: ffff88802c2d7828 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline] #1: ffff88802c2d7828 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline] #1: ffff88802c2d7828 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x249/0x13f0 kernel/fork.c:1518 7 locks held by syz-executor/5039: #0: ffff88801ecfe460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x295/0xd60 fs/read_write.c:590 #1: ffff88805b8c1c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffffffff8c344c48 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1662 #3: ffffffff8c1bda90 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2411 [inline] #3: ffffffff8c1bda90 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x196/0x5c0 kernel/cgroup/cgroup.c:2922 #4: ffffffff8c344e30 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2413 [inline] #4: ffffffff8c344e30 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x1ac/0x5c0 kernel/cgroup/cgroup.c:2922 #5: ffffffff8c352788 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xad/0x620 kernel/cgroup/cpuset.c:2348 #6: ffff88807dd06328 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline] #6: ffff88807dd06328 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0x33/0x2c0 mm/mempolicy.c:381 2 locks held by syz-executor/5041: #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline] #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline] #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x22c/0x13f0 kernel/fork.c:1518 #1: ffff88802c2d6a28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #1: ffff88802c2d6a28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline] #1: ffff88802c2d6a28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline] #1: ffff88802c2d6a28 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x249/0x13f0 kernel/fork.c:1518 1 lock held by udevd/5274: #0: ffffffff8c344e30 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x25e/0x20c0 kernel/exit.c:831 2 locks held by dhcpcd-run-hook/5287: #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline] #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline] #0: ffffffff8c3a9450 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x22c/0x13f0 kernel/fork.c:1518 #1: ffff88801a9b7128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #1: ffff88801a9b7128 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline] #1: ffff88801a9b7128 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline] #1: ffff88801a9b7128 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x249/0x13f0 kernel/fork.c:1518 ============================================= 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 05/09/2026 Call Trace: 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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3543 Comm: syslogd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:91 [inline] RIP: 0010:lock_release+0x10c/0x8a0 kernel/locking/lockdep.c:5636 Code: 65 8b 05 e7 d0 a4 7e 85 c0 0f 85 aa 04 00 00 65 48 8b 1d 57 c7 a4 7e 4c 8d b3 ec 0a 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 47 05 00 00 41 83 3e 00 0f 85 7d 04 00 00 48 89 5c 24 RSP: 0018:ffffc90002e1fd60 EFLAGS: 00000803 RAX: 0000000000000000 RBX: ffff88807e001dc0 RCX: e91aa6c456df8100 RDX: 0000000000000000 RSI: ffffffff8a7a09a0 RDI: ffffffff8a7a0960 RBP: ffffc90002e1fe80 R08: ffffffff8d8a06ef R09: 1ffffffff1b140dd R10: dffffc0000000000 R11: fffffbfff1b140de R12: 1ffff920005c3fb8 R13: dffffc0000000000 R14: ffff88807e0028ac R15: 0000000000000000 FS: 00007f0ef7d68c80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f360af05600 CR3: 000000001ee9d000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_write_seqcount_end include/linux/seqlock.h:565 [inline] vtime_user_exit+0x2c8/0x3e0 kernel/sched/cputime.c:732 __context_tracking_exit+0x4c/0x80 kernel/context_tracking.c:160 user_exit_irqoff include/linux/context_tracking.h:47 [inline] __enter_from_user_mode kernel/entry/common.c:22 [inline] syscall_enter_from_user_mode+0x56/0x70 kernel/entry/common.c:110 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f0ef7eb8407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffccf3f95d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f0ef7d68c80 RCX: 00007f0ef7eb8407 RDX: 00000000000000ff RSI: 000055a5cf712950 RDI: 0000000000000000 RBP: 000055a5cf712910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055a5cf7129a1 R13: 0000000000000000 R14: 000055a5cf712950 R15: 000055a5a2d43d98