INFO: task syz.0.17:5946 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17 state:D stack:29048 pid:5946 ppid:5900 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
rwsem_down_read_slowpath+0x517/0x880 kernel/locking/rwsem.c:1086
__down_read_common kernel/locking/rwsem.c:1250 [inline]
__down_read kernel/locking/rwsem.c:1263 [inline]
down_read+0x98/0x2e0 kernel/locking/rwsem.c:1522
inode_lock_shared include/linux/fs.h:814 [inline]
lookup_slow+0x46/0x70 fs/namei.c:1718
walk_component+0x2ad/0x3e0 fs/namei.c:2010
lookup_last fs/namei.c:2467 [inline]
path_lookupat+0x148/0x420 fs/namei.c:2491
filename_lookup+0x22d/0x580 fs/namei.c:2520
user_path_at_empty+0x42/0x60 fs/namei.c:2917
user_path_at include/linux/namei.h:57 [inline]
do_mount fs/namespace.c:3723 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2a8/0x3d0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd704b9de59
RSP: 002b:00007fd705ade028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd704e26090 RCX: 00007fd704b9de59
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007fd704c33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000200000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd704e26128 R14: 00007fd704e26090 R15: 00007ffd3b8478d8
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
1 lock held by dhcpcd/5433:
#0: ffff8880b8f3c298 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559
2 locks held by getty/5525:
#0: ffff8880314120a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217
2 locks held by syz.0.17/5945:
#0: ffff88802c012418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff88805e920160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff88805e920160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff88805e920160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.0.17/5946:
#0: ffff88805e920160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff88805e920160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by syz.1.19/5964:
#0: ffff888030ad0418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff88805e920730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff88805e920730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff88805e920730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.1.19/5965:
#0: ffff88805e920730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff88805e920730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by syz.2.20/5989:
#0: ffff888023998418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff88805e920d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff88805e920d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff88805e920d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.2.20/5990:
#0: ffff88805e920d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff88805e920d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by kworker/0:4/6006:
#0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
#0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730
#1: ffffc90003617d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
#1: ffffc90003617d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730
2 locks held by syz.3.21/6008:
#0: ffff88802707e418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff888077c98730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff888077c98730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff888077c98730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.3.21/6009:
#0: ffff888077c98730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff888077c98730 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by syz.4.22/6032:
#0: ffff88807cd4e418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff888077c98160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff888077c98160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff888077c98160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.4.22/6033:
#0: ffff888077c98160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff888077c98160 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by syz.5.23/6056:
#0: ffff88802f2ca418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff888077c98d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff888077c98d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff888077c98d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.5.23/6057:
#0: ffff888077c98d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff888077c98d00 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by syz.6.24/6085:
#0: ffff88805a74e418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff888077c992d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}
, at: inode_lock include/linux/fs.h:804 [inline]
, at: open_last_lookups fs/namei.c:3561 [inline]
, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.6.24/6086:
#0: ffff888077c992d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff888077c992d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by syz.7.25/6108:
#0: ffff88805df54418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff88805e9212d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff88805e9212d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff88805e9212d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.7.25/6109:
#0: ffff88805e9212d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff88805e9212d0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
2 locks held by syz.8.26/6133:
#0: ffff8880701a6418 (sb_writers
#13
){.+.+}-{0:0}
, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff888077c998a0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff888077c998a0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: open_last_lookups fs/namei.c:3561 [inline]
#1: ffff888077c998a0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: path_openat+0x7f4/0x3270 fs/namei.c:3794
1 lock held by syz.8.26/6134:
#0: ffff888077c998a0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
#0: ffff888077c998a0 (&sb->s_type->i_mutex_key#20){++++}-{3:3}, at: lookup_slow+0x46/0x70 fs/namei.c:1718
1 lock held by syz-executor/6139:
2 locks held by dhcpcd/6143:
#0: ffff888059778130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1780 [inline]
#0: ffff888059778130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd40 net/packet/af_packet.c:3264
#1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
#1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf59/0xfa0 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:__preempt_count_sub arch/x86/include/asm/preempt.h:85 [inline]
RIP: 0010:preempt_count_sub+0x5c/0x160 kernel/sched/core.c:5884
Code: 05 a1 4e a7 7e 89 c1 81 e1 ff ff ff 7f 39 cf 7f 25 81 ff ff 00 00 00 0f 93 c1 84 c0 0f 95 c0 08 c8 74 53 65 8b 05 7c 4e a7 7e <f7> df 65 01 3d 73 4e a7 7e 5b 5d c3 e8 a3 52 d1 02 85 c0 74 f4 48
RSP: 0018:ffffc90000117868 EFLAGS: 00000202
RAX: 0000000080000002 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8acacb60 RDI: 0000000000000001
RBP: ffffc90000117918 R08: ffffffff911e75f7 R09: 1ffffffff223cebe
R10: dffffc0000000000 R11: fffffbfff223cebf R12: dffffc0000000000
R13: ffff888059157000 R14: ffffffff97575ba0 R15: 1ffff92000022f10
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdf2651450 CR3: 000000000cf32000 CR4: 00000000003506e0
Call Trace:
<TASK>
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0xc5/0x120 kernel/locking/spinlock.c:194
__debug_check_no_obj_freed lib/debugobjects.c:1037 [inline]
debug_check_no_obj_freed+0x47b/0x520 lib/debugobjects.c:1058
slab_free_hook mm/slub.c:1786 [inline]
slab_free_freelist_hook+0xd2/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
__kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
skb_kfree_head net/core/skbuff.c:946 [inline]
skb_free_head net/core/skbuff.c:958 [inline]
skb_release_data+0x609/0x7f0 net/core/skbuff.c:988
skb_release_all net/core/skbuff.c:1054 [inline]
__kfree_skb net/core/skbuff.c:1068 [inline]
consume_skb+0xb2/0x110 net/core/skbuff.c:1284
nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline]
nsim_dev_trap_report_work+0x723/0xa90 drivers/net/netdevsim/dev.c:851
process_one_work kernel/workqueue.c:2653 [inline]
process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>