syzbot

INFO: task kworker/u8:0:12 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:0    state:D stack:21824 pid:12    tgid:12    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x1681/0x54c0 kernel/sched/core.c:7188
 __schedule_loop kernel/sched/core.c:7267 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7282
 rxrpc_destroy_all_calls+0x44e/0x570 net/rxrpc/call_object.c:752
 rxrpc_exit_net+0x6f/0xc0 net/rxrpc/net_ns.c:112
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x49f/0x940 net/core/net_namespace.c:252
 cleanup_net+0x56e/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 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>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
 #0: ffff88801b2a8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff88801b2a8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc90000117c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc90000117c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffffffff8f35d120 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
3 locks held by rcuc/1/28:
1 lock held by khungtaskd/38:
 #0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/5184:
2 locks held by getty/5571:
 #0: ffff888037bd50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
2 locks held by kworker/u8:4/9458:
 #0: ffff88801a08c938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff88801a08c938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc90020fe7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc90020fe7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
3 locks held by syz-executor/14690:
4 locks held by syz.0.3260/15159:
2 locks held by syz.8.3386/15474:
6 locks held by modprobe/15477:
4 locks held by syz-executor/15478:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 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+0xfd3/0x1030 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: 14690 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:unwind_next_frame+0x19f0/0x2550 arch/x86/kernel/unwind_orc.c:693
Code: 49 8d 56 40 4c 89 f7 4c 89 e6 e8 1b 0e 00 00 84 c0 0f 84 46 01 00 00 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 20 0f b6 04 28 <84> c0 0f 85 6a 08 00 00 b3 01 8b 84 24 8c 00 00 00 41 39 06 4c 8b
RSP: 0018:ffffc90004907698 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff90290cc4 RCX: 0000000000000001
RDX: ffffc900049077a8 RSI: dffffc0000000000 RDI: ffffc90004907d80
RBP: dffffc0000000000 R08: ffffc90004907d80 R09: 0000000000000000
R10: ffffc900049077b8 R11: fffff52000920ef9 R12: ffffc90004907d80
R13: 1ffff92000920eef R14: ffffc90004907768 R15: 1ffffffff2052198
FS:  000055556da76500(0000) GS:ffff8881260fb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc1ad15d480 CR3: 0000000064a30000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 __call_rcu_common kernel/rcu/tree.c:3131 [inline]
 call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
 __destroy_inode+0x2b2/0x640 fs/inode.c:369
 destroy_inode fs/inode.c:392 [inline]
 evict+0x8a7/0xb10 fs/inode.c:865
 __dentry_kill+0x1a2/0x690 fs/dcache.c:718
 finish_dput+0xc9/0x480 fs/dcache.c:927
 __fput+0x6a3/0xa70 fs/file_table.c:518
 fput_close_sync+0x11f/0x240 fs/file_table.c:615
 __do_sys_close fs/open.c:1507 [inline]
 __se_sys_close fs/open.c:1492 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1492
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f87a714d04e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffc076625b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 000055556da76500 RCX: 00007f87a714d04e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffc0766265c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000002e
R13: 00000000000927c0 R14: 00000000000c19e6 R15: 00007ffc076626b0
 </TASK>