INFO: task kworker/u8:2:36 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:2 state:D stack:21672 pid:36 tgid:36 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7058
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121
__debugfs_file_removed fs/debugfs/inode.c:769 [inline]
remove_one+0x312/0x420 fs/debugfs/inode.c:776
__simple_recursive_removal+0x15b/0x610 fs/libfs.c:631
debugfs_remove+0x5d/0x80 fs/debugfs/inode.c:799
nsim_dev_health_exit+0x3b/0xe0 drivers/net/netdevsim/health.c:227
nsim_dev_reload_destroy+0x144/0x4d0 drivers/net/netdevsim/dev.c:1710
nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:983
devlink_reload+0x19e/0x7c0 net/devlink/dev.c:461
devlink_pernet_pre_exit+0x1a0/0x2b0 net/devlink/core.c:509
ops_pre_exit_list net/core/net_namespace.c:160 [inline]
ops_undo_list+0x184/0xab0 net/core/net_namespace.c:233
cleanup_net+0x408/0x890 net/core/net_namespace.c:682
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task syz.4.779:10119 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.779 state:D stack:28872 pid:10119 tgid:10118 ppid:9834 task_flags:0x400040 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7058
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x81b/0x1060 kernel/locking/mutex.c:760
devlink_health_report+0x3ba/0x9c0 net/devlink/health.c:627
nsim_dev_health_break_write+0x166/0x210 drivers/net/netdevsim/health.c:162
full_proxy_write+0x131/0x1a0 fs/debugfs/file.c:388
vfs_write+0x2a0/0x11d0 fs/read_write.c:684
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f785a58ebe9
RSP: 002b:00007f785b3a5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f785a7b5fa0 RCX: 00007f785a58ebe9
RDX: 0000000000000006 RSI: 0000200000005900 RDI: 0000000000000004
RBP: 00007f785a611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f785a7b6038 R14: 00007f785a7b5fa0 R15: 00007fffcc8a4c08
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e5c10a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5c10a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e5c10a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:2/36:
#0: ffff88801c6fe948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
#1: ffffc90000ac7d10 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
#2: ffffffff903708d0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x890 net/core/net_namespace.c:658
#3: ffff8880290b90e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#3: ffff8880290b90e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
#3: ffff8880290b90e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x12c/0x2b0 net/devlink/core.c:506
#4: ffff8880290ba250 (&devlink->lock_key){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
#4: ffff8880290ba250 (&devlink->lock_key){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
#4: ffff8880290ba250 (&devlink->lock_key){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x136/0x2b0 net/devlink/core.c:506
#5: ffff88806a0e9ac0 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
#5: ffff88806a0e9ac0 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: __simple_recursive_removal+0x354/0x610 fs/libfs.c:627
3 locks held by kworker/0:2/950:
#0: ffff88801b880d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
#1: ffffc90003a47d10 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
#2: ffffffff8e5cc638 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by syz-executor/5867:
#0: ffffffff90386bc8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff90386bc8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3433
2 locks held by getty/7672:
#0: ffff88803142b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000339b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
3 locks held by syz.4.779/10119:
#0: ffff88801d289b38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232
#1: ffff88801fee2428 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#2: ffff8880290ba250 (&devlink->lock_key){+.+.}-{4:4}, at: devlink_health_report+0x3ba/0x9c0 net/devlink/health.c:627
1 lock held by syz.0.1025/11371:
#0: ffff88806a0e9ac0 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:884 [inline]
#0: ffff88806a0e9ac0 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3806 [inline]
#0: ffff88806a0e9ac0 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: path_openat+0x818/0x2cb0 fs/namei.c:4043
1 lock held by syz.5.1178/12247:
#0: ffffffff90386bc8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff90386bc8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3433
3 locks held by syz.3.1189/12306:
#0: ffffffff903708d0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:566
#1: ffffffff90386bc8 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:172 [inline]
#1: ffffffff90386bc8 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7e9/0xab0 net/core/net_namespace.c:247
#2: ffffffff8e5cc638 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf0e/0x1260 kernel/hung_task.c:491
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245