INFO: task kworker/u8:8:2237 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:8 state:D stack:21784 pid:2237 tgid:2237 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
afs_cell_purge+0x3d9/0x540 fs/afs/cell.c:894
afs_net_exit+0x50/0x100 fs/afs/main.c:147
ops_exit_list net/core/net_namespace.c:199 [inline]
ops_undo_list+0x49a/0x990 net/core/net_namespace.c:252
cleanup_net+0x4de/0x820 net/core/net_namespace.c:695
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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:
1 lock held by khungtaskd/38:
#0: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5aa880 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:8/2237:
#0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc90006b37ba0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc90006b37ba0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffffffff8e856560 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x820 net/core/net_namespace.c:669
1 lock held by udevd/5167:
#0: ffff888036beda08 (&ep->lock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock_rt.h:93 [inline]
#0: ffff888036beda08 (&ep->lock){+.+.}-{3:3}, at: ep_poll fs/eventpoll.c:2040 [inline]
#0: ffff888036beda08 (&ep->lock){+.+.}-{3:3}, at: do_epoll_wait+0x848/0xbb0 fs/eventpoll.c:2473
2 locks held by getty/5558:
#0: ffff88823bf2c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
1 lock held by udevd/7543:
#0: ffff888148c4eea8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#0: ffff888148c4eea8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_llseek+0x6d/0xc0 block/fops.c:611
1 lock held by udevd/7544:
7 locks held by udevd/7784:
1 lock held by udevd/7793:
2 locks held by syz.7.525/9978:
1 lock held by syz.8.530/10001:
3 locks held by syz.1.526/10010:
4 locks held by dhcpcd-run-hook/10014:
1 lock held by udevadm/10015:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/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+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 10001 Comm: syz.8.530 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:_compound_head include/linux/page-flags.h:284 [inline]
RIP: 0010:PageSlab include/linux/page-flags.h:1062 [inline]
RIP: 0010:page_table_check_set+0x8b/0x730 mm/page_table_check.c:109
Code: 05 ba 18 d2 0a 48 c1 e3 06 48 89 c5 4c 8d 24 18 49 83 c4 08 4d 89 e6 49 c1 ee 03 48 b8 00 00 00 00 00 fc ff df 41 80 3c 06 00 <74> 08 4c 89 e7 e8 ab 3f f9 ff 48 01 dd 49 8b 1c 24 48 89 de 48 83
RSP: 0000:ffffc9000deefbc0 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: 00000000004699c0 RCX: dffffc0000000000
RDX: 0000000000000002 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffea0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100578e9c9 R12: ffffea00004699c8
R13: 0000000000000000 R14: 1ffffd400008d339 R15: 0000000000000001
FS: 00007fc08f3866c0(0000) GS:ffff888126df7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc087ddf000 CR3: 0000000067e40000 CR4: 00000000003526f0
Call Trace:
page_table_check_ptes_set include/linux/page_table_check.h:76 [inline]
set_ptes+0x231/0x240 include/linux/pgtable.h:292
do_anonymous_page mm/memory.c:5234 [inline]
do_pte_missing mm/memory.c:4360 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault mm/memory.c:6336 [inline]
handle_mm_fault+0x2736/0x3400 mm/memory.c:6505
do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7fc090fe09e6
Code: f0 72 6e 48 63 cd 48 01 c1 49 39 4f 08 72 4c 8d 4d ff 85 ed 74 33 66 0f 1f 44 00 00 48 39 f0 72 1b 4d 8b 07 49 89 c1 49 29 f1 <47> 0f b6 0c 08 45 84 c9 74 08 45 88 0c 00 49 8b 47 10 48 83 c0 01
RSP: 002b:00007fc08f3854a0 EFLAGS: 00010206
RAX: 0000000000e79001 RBX: 00007fc08f385540 RCX: 0000000000000058
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007fc08f3855e0
RBP: 0000000000000102 R08: 00007fc086f66000 R09: 0000000000e79000
R10: 0000000000000000 R11: 00007fc08f385550 R12: 0000000000000001
R13: 00007fc0911bdc40 R14: 0000000000000000 R15: 00007fc08f3855e0