INFO: task syz.6.957:13970 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.957 state:D stack:25792 pid:13970 tgid:13965 ppid:10420 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x14fb/0x52c0 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285
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: 0033:0x7f30ed9cb507
RSP: 002b:00007f30ebbfce58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f30ebbfcee0 RCX: 00007f30ed9cb507
RDX: 00000000000001ff RSI: 0000200000000300 RDI: 00000000ffffff9c
RBP: 0000200000000140 R08: 00002000000002c0 R09: 0000000000000000
R10: 0000200000000140 R11: 0000000000000246 R12: 0000200000000300
R13: 00007f30ebbfcea0 R14: 0000000000000000 R15: 0000000000000000
Showing all locks held in the system:
1 lock held by khungtaskd/39:
#0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5552:
#0: ffff8880364370a0 (&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+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:4/5808:
#0: ffff888019c03d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff888019c03d38 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
#1: ffffc90005087c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc90005087c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
#2: ffff888061ff0260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490
7 locks held by syz.6.957/13966:
2 locks held by syz.6.957/13970:
#0: ffff8880366de480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
#1: ffff88806af96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline]
#1: ffff88806af96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline]
#1: ffff88806af96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline]
#1: ffff88806af96f90 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4922
2 locks held by udevd/14879:
4 locks held by syz-executor/15206:
2 locks held by syz.5.1142/15652:
4 locks held by syz.1.1145/15655:
2 locks held by dhcpcd-run-hook/15670:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 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:467
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15655 Comm: syz.1.1145 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:stack_trace_consume_entry+0x6e/0x280 kernel/stacktrace.c:89
Code: 0f b6 44 15 00 84 c0 0f 85 22 01 00 00 45 3b 0e 73 3a 48 8d 5f 0c 49 89 df 49 c1 ef 03 41 0f b6 04 17 84 c0 0f 85 47 01 00 00 <44> 8b 23 45 85 e4 74 21 41 ff cc 41 0f b6 04 17 84 c0 0f 85 78 01
RSP: 0018:ffffc900057f7138 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc900057f724c RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff822a53ed RDI: ffffc900057f7240
RBP: 1ffff92000afee4a R08: ffffc900057f7250 R09: 0000000000000001
R10: ffffc900057f71d8 R11: ffffffff81af6870 R12: ffff888030720000
R13: 1ffff92000afee49 R14: ffffc900057f7248 R15: 1ffff92000afee49
FS: 0000000000000000(0000) GS:ffff888126343000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf75a13000 CR3: 0000000079ef4000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x10f/0x150 arch/x86/kernel/stacktrace.c:27
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3131 [inline]
call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
slab_free_hook mm/slub.c:2651 [inline]
slab_free mm/slub.c:6124 [inline]
kmem_cache_free+0x50e/0x6b0 mm/slub.c:6254
anon_vma_free mm/rmap.c:137 [inline]
__put_anon_vma+0x12a/0x310 mm/rmap.c:2889
put_anon_vma mm/internal.h:215 [inline]
unlink_anon_vmas+0x58b/0x730 mm/rmap.c:529
free_pgtables+0x836/0xb70 mm/memory.c:427
exit_mmap+0x490/0xa10 mm/mmap.c:1314
__mmput+0xcb/0x3d0 kernel/fork.c:1174
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x62e/0x2320 kernel/exit.c:959
do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
get_signal+0x125c/0x1310 kernel/signal.c:3034
arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c8c39c629
Code: Unable to access opcode bytes at 0x7f1c8c39c5ff.
RSP: 002b:00007f1c8a5f60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f1c8c615fa8 RCX: 00007f1c8c39c629
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1c8c615fa8
RBP: 00007f1c8c615fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c8c616038 R14: 00007ffd9e8c6d70 R15: 00007ffd9e8c6e58