INFO: task kworker/u8:15:4540 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:15 state:D stack:22648 pid:4540 tgid:4540 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
afs_cell_purge+0x41f/0x4f0 fs/afs/cell.c:894
afs_net_exit+0x83/0x140 fs/afs/main.c:147
ops_exit_list net/core/net_namespace.c:199 [inline]
ops_undo_list+0x2eb/0xab0 net/core/net_namespace.c:252
cleanup_net+0x41b/0x8b0 net/core/net_namespace.c:695
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x672/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
2 locks held by ksoftirqd/1/23:
1 lock held by khungtaskd/31:
#0: ffffffff8e3c44a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c44a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c44a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5575:
#0: ffff88814ceb60a0 (&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/0x14f0 drivers/tty/n_tty.c:2222
4 locks held by kworker/u8:10/4531:
3 locks held by kworker/u8:15/4540:
#0: ffff88801ba94948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc9000495fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff900e4430 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669
5 locks held by kworker/u8:0/10149:
1 lock held by syz.5.11178/27035:
3 locks held by syz.5.11188/27060:
#0: ffffffff900e4430 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x2d6/0x690 net/core/net_namespace.c:576
#1: ffffffff900fa848 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#1: ffffffff900fa848 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7e9/0xab0 net/core/net_namespace.c:248
#2: ffffffff8e3cfa38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x672/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 27035 Comm: syz.5.11178 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:hlock_class+0x13/0x70 kernel/locking/lockdep.c:234
Code: 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f b7 47 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 0d f3 12 14 <73> 15 48 8d 04 80 48 8d 04 80 48 8d 04 c5 a0 d9 aa 95 c3 cc cc cc
RSP: 0018:ffffc9000fd5f078 EFLAGS: 00000003
RAX: 0000000000000007 RBX: ffff88806538d430 RCX: 0000000000020000
RDX: 0000000000000007 RSI: 0000000000000000 RDI: ffff88806538d430
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88806538d430
R13: ffff88806538c900 R14: 0000000000000000 R15: ffffffff8e3c44a0
FS: 0000000000000000(0000) GS:ffff8881249df000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f238fdb2698 CR3: 0000000073fb8000 CR4: 00000000003526f0
DR0: fffffffffffffffc DR1: 0000000000000004 DR2: 0000000000000001
DR3: 0000000000000002 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
check_wait_context kernel/locking/lockdep.c:4854 [inline]
__lock_acquire+0x218/0x1ce0 kernel/locking/lockdep.c:5187
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
__page_table_check_zero+0x13d/0x5d0 mm/page_table_check.c:138
page_table_check_free include/linux/page_table_check.h:43 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
free_unref_folios+0xa4f/0x1610 mm/page_alloc.c:2963
folios_put_refs+0x4be/0x750 mm/swap.c:1002
folio_batch_release include/linux/pagevec.h:101 [inline]
shmem_undo_range+0x58f/0x1150 mm/shmem.c:1120
shmem_truncate_range mm/shmem.c:1232 [inline]
shmem_evict_inode+0x3a1/0xbe0 mm/shmem.c:1360
evict+0x3e3/0x920 fs/inode.c:810
iput_final fs/inode.c:1914 [inline]
iput.part.0+0x6a9/0xb00 fs/inode.c:1966
iput+0x35/0x40 fs/inode.c:1929
dentry_unlink_inode+0x29c/0x480 fs/dcache.c:466
__dentry_kill+0x1d0/0x600 fs/dcache.c:669
dput.part.0+0x4b1/0x9b0 fs/dcache.c:911
dput+0x1f/0x30 fs/dcache.c:901
__fput+0x51c/0xb70 fs/file_table.c:476
task_work_run+0x14d/0x240 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x86f/0x2bf0 kernel/exit.c:966
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:40 [inline]
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
irqentry_exit_to_user_mode+0x176/0x310 kernel/entry/common.c:73
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fc7d018eed1
Code: Unable to access opcode bytes at 0x7fc7d018eea7.
RSP: 002b:fffffffffffffe90 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fc7d03e5fa0 RCX: 00007fc7d018eec9
RDX: 0000000000000000 RSI: fffffffffffffe90 RDI: 0000000000008000
RBP: 00007fc7d0211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fc7d03e6038 R14: 00007fc7d03e5fa0 R15: 00007ffcf8fcd2d8