INFO: task syz.7.5724:22695 blocked for more than 143 seconds.
Ta[ 1165.967602][ T39] Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.5724 state:D stack:26944 pid:22695 tgid:22694 ppid:20254 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x1709/0x5530 kernel/sched/core.c:7231
__schedule_loop kernel/sched/core.c:7308 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7604
rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
bdev_open+0xde/0xd00 block/bdev.c:991
bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1105
fs_bdev_file_open_by_dev fs/super.c:1708 [inline]
setup_bdev_super+0x5a/0x680 fs/super.c:1800
get_tree_bdev_flags+0x388/0x4f0 fs/super.c:1879
vfs_get_tree+0x92/0x2a0 fs/super.c:1941
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3777 [inline]
do_new_mount+0x319/0xdc0 fs/namespace.c:3853
do_mount fs/namespace.c:4186 [inline]
__do_sys_mount fs/namespace.c:4402 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4379
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe563f8de59
RSP: 002b:00007fe5621e6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe564215fa0 RCX: 00007fe563f8de59
RDX: 0000200000000000 RSI: 00002000000000c0 RDI: 0000200000000040
RBP: 00007fe564023e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe564216038 R14: 00007fe564215fa0 R15: 00007fff5b986668
Showing all locks held in the system:
11 locks held by ktimers/0/16:
#0: ffffffff8e2592e0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#1: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#2: ffff8880b8626260 (&base->expiry_lock){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff8880b8626260 (&base->expiry_lock){+...}-{3:3}, at: timer_base_lock_expiry kernel/time/timer.c:1502 [inline]
#2: ffff8880b8626260 (&base->expiry_lock){+...}-{3:3}, at: __run_timer_base+0x11a/0x9b0 kernel/time/timer.c:2384
#3: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#3: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#4: ffffc90000157a80 ((&ndev->rs_timer)){+...}-{0:0}, at: call_timer_fn+0xd4/0x5e0 kernel/time/timer.c:1745
#5: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#5: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x203/0x1650 net/ipv6/ndisc.c:482
#6: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#6: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#6: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x11e/0x540 net/ipv6/ip6_output.c:234
#7: ffffffff8e2592e0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#8: ffffffff8f8ef638 (&tbl->lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock_rt.h:90 [inline]
#8: ffffffff8f8ef638 (&tbl->lock){+...}-{3:3}, at: neigh_forced_gc net/core/neighbour.c:265 [inline]
#8: ffffffff8f8ef638 (&tbl->lock){+...}-{3:3}, at: neigh_alloc net/core/neighbour.c:509 [inline]
#8: ffffffff8f8ef638 (&tbl->lock){+...}-{3:3}, at: ___neigh_create+0x22b/0x23a0 net/core/neighbour.c:652
#9: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#9: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#9: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#9: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#10: ffffffff8e2592e0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
1 lock held by khungtaskd/39:
#0: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e3c37c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6821
2 locks held by getty/5352:
#0: ffff888032cf20a0 (&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+0x460/0x1360 drivers/tty/n_tty.c:2211
1 lock held by udevd/5611:
#0: ffff8880280f64c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:991
2 locks held by syz.7.5724/22695:
#0: ffff888025c400e0 (&type->s_umount_key#78/1){+.+.}-{4:4}, at: alloc_super fs/super.c:365 [inline]
#0: ffff888025c400e0 (&type->s_umount_key#78/1){+.+.}-{4:4}, at: sget_fc+0x97c/0x1a60 fs/super.c:889
#1: ffff8880280f64c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:991
3 locks held by syz.1.6223/24122:
#0: ffff88803342a928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888037564510 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2731 [inline]
#1: ffff888037564510 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffff88805c88e078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
3 locks held by syz.0.6238/24253:
#0: ffff888038613b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888037564510 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2731 [inline]
#1: ffff888037564510 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffff88805e6cbc78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
1 lock held by syz.0.6238/24254:
#0: ffff888038613b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
1 lock held by syz.3.6648/25747:
#0: ffff8880326680e8 (&kvm->slots_lock){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#0: ffff8880326680e8 (&kvm->slots_lock){+.+.}-{4:4}, at: kvm_vm_ioctl_set_memory_region+0x67/0xa0 virt/kvm/kvm_main.c:2146
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
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+0xfd7/0x1030 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
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3804 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3823 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3878 [inline]
RIP: 0010:__lock_acquire+0xb5e/0x2e40 kernel/locking/lockdep.c:5240
Code: 24 48 bb eb 83 b5 80 46 86 c8 61 48 0f af dd 48 c1 eb 2d 48 8b 04 dd 00 b5 85 93 48 85 c0 74 1c 48 83 c0 f8 74 16 48 8b 48 18 <48> 39 e9 0f 84 d4 01 00 00 48 8b 40 08 48 85 c0 75 e4 e8 8b d4 ff
RSP: 0018:ffffc90000157558 EFLAGS: 00000093
RAX: ffffffff9451a170 RBX: 00000000000051e7 RCX: d69901cd65aec423
RDX: 000000009ba0e7e1 RSI: 000000000e21d8b4 RDI: ffff88801deb8000
RBP: a167fe424c27c272 R08: c300000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880b8636b68 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88801deb8d30 R15: 0000000000000007
FS: 0000000000000000(0000) GS:ffff888125a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e316000 CR3: 0000000042330000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 8000000000000001
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5892
rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
spin_lock include/linux/spinlock_rt.h:45 [inline]
get_random_u32+0x1db/0x860 drivers/char/random.c:541
get_random_u32_below include/linux/random.h:86 [inline]
get_random_u32_inclusive include/linux/random.h:115 [inline]
rfc3315_s14_backoff_update+0x14/0xc0 net/ipv6/addrconf.c:116
addrconf_rs_timer+0x324/0x6c0 net/ipv6/addrconf.c:4078
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x67b/0x9b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626
__do_softirq kernel/softirq.c:660 [inline]
run_ktimerd+0x69/0x100 kernel/softirq.c:1155
smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
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