INFO: task kworker/u8:30:12789 blocked for more than 163 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:30 state:D stack:22888 pid:12789 tgid:12789 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
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:751 [inline]
remove_one+0x312/0x420 fs/debugfs/inode.c:758
__simple_recursive_removal+0x15b/0x610 fs/libfs.c:623
debugfs_remove+0x5d/0x80 fs/debugfs/inode.c:781
nsim_dev_health_exit+0x3b/0xe0 drivers/net/netdevsim/health.c:227
nsim_dev_reload_destroy+0x144/0x4d0 drivers/net/netdevsim/dev.c:1766
nsim_dev_reload_down+0x66/0xd0 drivers/net/netdevsim/dev.c:1038
devlink_reload+0x1a1/0x7c0 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:161 [inline]
ops_undo_list+0x187/0xab0 net/core/net_namespace.c:234
cleanup_net+0x41b/0x830 net/core/net_namespace.c:696
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
INFO: task syz.4.2960:17579 blocked for more than 164 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.2960 state:D stack:28792 pid:17579 tgid:17576 ppid:17071 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc69/0x1ca0 kernel/locking/mutex.c:776
devlink_health_report+0x6b4/0xaa0 net/devlink/health.c:680
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/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe64858f7c9
RSP: 002b:00007fe6493fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe6487e5fa0 RCX: 00007fe64858f7c9
RDX: 0000000000000006 RSI: 0000200000005900 RDI: 0000000000000004
RBP: 00007fe648613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe6487e6038 R14: 00007fe6487e5fa0 R15: 00007ffffb0ff328
Showing all locks held in the system:
1 lock held by ksoftirqd/1/23:
#0: ffff8880b843add8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:647 [inline]
#0: ffff8880b843add8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:632
1 lock held by khungtaskd/31:
#0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
1 lock held by klogd/5192:
#0: ffff8880b843add8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:647 [inline]
#0: ffff8880b843add8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:632
2 locks held by getty/5597:
#0: ffff88803593a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x1510 drivers/tty/n_tty.c:2211
2 locks held by kworker/u8:22/6454:
#0: ffff888144eb0948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232
#1: ffffc9000b827c90 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233
6 locks held by kworker/u8:30/12789:
#0: ffff88801badf148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232
#1: ffffc90019137c90 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233
#2: ffffffff9012e9d0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x830 net/core/net_namespace.c:670
#3: ffff888028c580e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#3: ffff888028c580e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
#3: ffff888028c580e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x12c/0x2b0 net/devlink/core.c:506
#4: ffff888045203250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
#4: ffff888045203250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
#4: ffff888045203250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x136/0x2b0 net/devlink/core.c:506
#5: ffff88805a5f4b58 (&sb->s_type->i_mutex_key#9/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline]
#5: ffff88805a5f4b58 (&sb->s_type->i_mutex_key#9/2){+.+.}-{4:4}, at: __simple_recursive_removal+0x354/0x610 fs/libfs.c:619
3 locks held by syz.4.2960/17579:
#0: ffff888026b4f278 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1255
#1: ffff8881416f0420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#2: ffff888045203250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devlink_health_report+0x6b4/0xaa0 net/devlink/health.c:680
2 locks held by syz.0.3365/19185:
#0: ffff8881416f0420 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:4529 [inline]
#0: ffff8881416f0420 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0x183a/0x3140 fs/namei.c:4784
#1: ffff88805a5f4b58 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline]
#1: ffff88805a5f4b58 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: open_last_lookups fs/namei.c:4539 [inline]
#1: ffff88805a5f4b58 (&sb->s_type->i_mutex_key#17){++++}-{4:4}, at: path_openat+0x1248/0x3140 fs/namei.c:4784
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x133/0x180 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xe66/0x1180 kernel/hung_task.c:515
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 19141 Comm: kworker/u8:3 Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: krdsd rds_connect_worker
RIP: 0010:ref_tracker_free+0x83/0x830 lib/ref_tracker.c:296
Code: f3 65 48 8b 05 d6 51 d3 0e 48 89 84 24 e8 00 00 00 31 c0 e8 af 7c df fc 31 c0 b9 10 00 00 00 4c 8d 6c 24 30 4c 89 ef f3 48 ab <48> 8d 7d 4c 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 42 0f b6 04 30
RSP: 0018:ffffc900031278a0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88807b4fb818 RCX: 0000000000000000
RDX: ffff8880930d1e80 RSI: ffffffff84deee41 RDI: ffffc90003127950
RBP: ffff88803209a850 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880930d29b0 R12: 1ffff92000624f16
R13: ffffc900031278d0 R14: dffffc0000000000 R15: ffff88803209a738
FS: 0000000000000000(0000) GS:ffff8881249fc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9178bb6ad8 CR3: 00000000761ac000 CR4: 00000000003526f0
Call Trace:
__netns_tracker_free include/net/net_namespace.h:379 [inline]
sk_net_refcnt_upgrade+0x9c/0x350 net/core/sock.c:2392
rds_tcp_tune+0x2bb/0x910 net/rds/tcp.c:507
rds_tcp_conn_path_connect+0x305/0x7f0 net/rds/tcp_connect.c:127
rds_connect_worker+0x1af/0x2c0 net/rds/threads.c:176
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246