INFO: task kworker/u8:5:1020 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5 state:D stack:20832 pid:1020 tgid:1020 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
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:198 [inline]
ops_undo_list+0x49a/0x990 net/core/net_namespace.c:251
cleanup_net+0x4c5/0x800 net/core/net_namespace.c:682
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
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/31:
#0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:5/1020:
#0: ffff88801b2f6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801b2f6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000373fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000373fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8f52b5b0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:658
2 locks held by getty/5618:
#0: ffff88814d3be0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
7 locks held by syz.6.2343/15728:
2 locks held by syz.7.2348/15739:
=============================================
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_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:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 15739 Comm: syz.7.2348 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:____rb_erase_color lib/rbtree.c:262 [inline]
RIP: 0010:rb_erase+0x7b7/0xe60 lib/rbtree.c:445
Code: 74 08 48 89 df e8 89 ec ad f6 48 8b 1b 48 85 db 74 1e 48 89 d8 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 6c ec ad f6 f6 03 01 <0f> 84 5d 02 00 00 48 89 e8 49 8d 6c 24 10 49 89 ee 49 c1 ee 03 41
RSP: 0018:ffffc90000a08ca8 EFLAGS: 00000046
RAX: 1ffff920016bbfa8 RBX: ffffc9000b5dfd40 RCX: dffffc0000000000
RDX: 0000000000010000 RSI: ffff8880b8727b50 RDI: ffffc90002ec7d48
RBP: dffffc0000000000 R08: ffffffff8fa38637 R09: 1ffffffff1f470c6
R10: dffffc0000000000 R11: fffffbfff1f470c7 R12: ffffc90004d5fd40
R13: ffffc90004d5fd40 R14: 1ffff920009abfa8 R15: 1ffff110170e507d
FS: 00007fb93b2836c0(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb93a3716c0 CR3: 00000000500b4000 CR4: 0000000000350ef0
Call Trace:
rb_erase_cached include/linux/rbtree.h:126 [inline]
timerqueue_del+0xae/0x100 lib/timerqueue.c:57
__remove_hrtimer kernel/time/hrtimer.c:1121 [inline]
__run_hrtimer kernel/time/hrtimer.c:1741 [inline]
__hrtimer_run_queues+0x364/0xc60 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2061 [inline]
RIP: 0010:vprintk_emit+0x58f/0x7a0 kernel/printk/printk.c:2449
Code: 85 32 01 00 00 e8 11 87 1f 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 00 87 1f 00 eb 06 e8 f9 86 1f 00 fb 48 c7 c7 80 e1 12 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 b9 35
RSP: 0018:ffffc9000e227640 EFLAGS: 00000287
RAX: ffffffff81a02487 RBX: ffffffff81a02344 RCX: 0000000000080000
RDX: ffffc9000d04e000 RSI: 000000000000c9f8 RDI: ffffffff8e12e180
RBP: ffffc9000e227750 R08: ffffffff8fa38637 R09: 1ffffffff1f470c6
R10: dffffc0000000000 R11: fffffbfff1f470c7 R12: dffffc0000000000
R13: 1ffff92001c44ecc R14: 0000000000000200 R15: 0000000000000058
_printk+0xcf/0x120 kernel/printk/printk.c:2475
_btrfs_printk+0x4eb/0x5b0 fs/btrfs/messages.c:251
device_list_add+0x1bfd/0x22a0 fs/btrfs/volumes.c:824
btrfs_scan_one_device+0x3ee/0x650 fs/btrfs/volumes.c:1493
btrfs_get_tree_super fs/btrfs/super.c:1853 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2077 [inline]
btrfs_get_tree+0x433/0x1820 fs/btrfs/super.c:2111
vfs_get_tree+0x92/0x2b0 fs/super.c:1815
do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808
do_mount fs/namespace.c:4136 [inline]
__do_sys_mount fs/namespace.c:4347 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4324
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb93a39038a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb93b282e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fb93b282ef0 RCX: 00007fb93a39038a
RDX: 00002000000055c0 RSI: 0000200000000280 RDI: 00007fb93b282eb0
RBP: 00002000000055c0 R08: 00007fb93b282ef0 R09: 0000000002000898
R10: 0000000002000898 R11: 0000000000000246 R12: 0000200000000280
R13: 00007fb93b282eb0 R14: 00000000000055ae R15: 00002000000002c0