INFO: task syz.6.254:7813 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.254 state:D stack:24576 pid:7813 tgid:7812 ppid:6203 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244
inode_lock_nested include/linux/fs.h:1073 [inline]
__start_dirop fs/namei.c:2923 [inline]
start_dirop fs/namei.c:2934 [inline]
filename_create+0x200/0x370 fs/namei.c:4922
filename_mkdirat+0xd2/0x520 fs/namei.c:5259
__do_sys_mkdirat fs/namei.c:5287 [inline]
__se_sys_mkdirat+0x35/0x150 fs/namei.c:5284
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f68e4fdb607
RSP: 002b:00007f68e322de58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f68e322dee0 RCX: 00007f68e4fdb607
RDX: 00000000000001ff RSI: 0000200000000380 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000380
R13: 00007f68e322dea0 R14: 0000000000000000 R15: 0000000000000000
Showing all locks held in the system:
4 locks held by pr/legacy/17:
2 locks held by rcuc/0/20:
7 locks held by ktimers/1/29:
1 lock held by khungtaskd/37:
#0: ffffffff8ddcba00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcba00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcba00 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/1:1/43:
#0: ffff888019c07938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff888019c07938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc90000b47c40 ((work_completion)(&p->wq)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc90000b47c40 ((work_completion)(&p->wq)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
#2: ffff888019c158f8 (&vn->busy.lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff888019c158f8 (&vn->busy.lock){+.+.}-{3:3}, at: find_unlink_vmap_area+0x82/0x2e0 mm/vmalloc.c:2540
1 lock held by udevd/5168:
#0: ffff888039768208 (&ep->lock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock_rt.h:96 [inline]
#0: ffff888039768208 (&ep->lock){+.+.}-{3:3}, at: ep_poll fs/eventpoll.c:2040 [inline]
#0: ffff888039768208 (&ep->lock){+.+.}-{3:3}, at: do_epoll_wait+0x851/0xbd0 fs/eventpoll.c:2462
2 locks held by getty/5557:
#0: ffff888032f2d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
2 locks held by syz.6.254/7813:
#0: ffff8880368d6480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
#1: ffff8880616a9090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline]
#1: ffff8880616a9090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline]
#1: ffff8880616a9090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline]
#1: ffff8880616a9090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4922
6 locks held by syz.6.254/7814:
7 locks held by udevd/8670:
1 lock held by udevd/8737:
5 locks held by syz.6.343/9117:
2 locks held by syz.9.346/9131:
3 locks held by syz.8.351/9160:
4 locks held by syz.0.349/9165:
2 locks held by syz.5.352/9170:
3 locks held by dhcpcd-run-hook/9172:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline]
watchdog+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
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: 29 Comm: ktimers/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:check_preemption_disabled+0x29/0xe0 lib/smp_processor_id.c:19
Code: 90 55 41 57 41 56 53 65 8b 05 47 03 2b 07 65 8b 0d 3c 03 2b 07 f7 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f 5d e9 99 a5 03 00 cc 9c <59> f7 c1 00 02 00 00 74 ea 65 4c 8b 3d ee 02 2b 07 41 f6 47 2f 04
RSP: 0018:ffffc90000a3f0d8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 00000000ffffffff RCX: 0000000080000000
RDX: 0000000000000100 RSI: ffffffff8d57bbe6 RDI: ffffffff8ba66e00
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000100
R10: ffffc90000a3f220 R11: fffff52000147e46 R12: 0000000000000246
R13: ffff88801ceebd00 R14: ffffffff8ddcba00 R15: ffffc90000a3f398
FS: 0000000000000000(0000) GS:ffff888126439000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b1fa856950 CR3: 0000000059212000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
lock_is_held_type+0x5a/0x150 kernel/locking/lockdep.c:5939
__find_rr_leaf+0x353/0x760 net/ipv6/route.c:833
find_rr_leaf net/ipv6/route.c:889 [inline]
rt6_select net/ipv6/route.c:933 [inline]
fib6_table_lookup+0x3b5/0xa80 net/ipv6/route.c:2247
ip6_pol_route+0x228/0x13d0 net/ipv6/route.c:2283
pol_lookup_func include/net/ip6_fib.h:617 [inline]
fib6_rule_lookup+0x556/0x730 net/ipv6/fib6_rules.c:120
ip6_route_input_lookup net/ipv6/route.c:2352 [inline]
ip6_route_input+0x730/0xad0 net/ipv6/route.c:2655
ip6_rcv_finish+0x141/0x280 net/ipv6/ip6_input.c:77
NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6164 [inline]
__netif_receive_skb net/core/dev.c:6277 [inline]
process_backlog+0x3ce/0xc60 net/core/dev.c:6628
__napi_poll+0xaf/0x580 net/core/dev.c:7692
napi_poll net/core/dev.c:7755 [inline]
net_rx_action+0x696/0xe00 net/core/dev.c:7912
handle_softirqs+0x1de/0x6f0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
run_ktimerd+0x69/0x100 kernel/softirq.c:1138
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245