INFO: tas[ 623.626807][ T38] INFO: task syz.1.778:10987 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.778 state:D stack:24824 pid:10987 tgid:10981 ppid:10235 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x147b/0x4f50 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7241
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked+0x1fc5/0x2600 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:1072 [inline]
__start_dirop fs/namei.c:2873 [inline]
start_dirop fs/namei.c:2884 [inline]
filename_create+0x200/0x370 fs/namei.c:4888
do_mkdirat+0xd2/0x4c0 fs/namei.c:5165
__do_sys_mkdirat fs/namei.c:5195 [inline]
__se_sys_mkdirat fs/namei.c:5193 [inline]
__x64_sys_mkdirat+0x87/0xa0 fs/namei.c:5193
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1462e49b97
RSP: 002b:00007f1461084e58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f1461084ee0 RCX: 00007f1462e49b97
RDX: 00000000000001ff RSI: 0000200000001800 RDI: 00000000ffffff9c
RBP: 0000200000000f40 R08: 0000200000001780 R09: 0000000000000000
R10: 0000200000000f40 R11: 0000000000000246 R12: 0000200000001800
R13: 00007f1461084ea0 R14: 0000000000000000 R15: 0000200000001880
Showing all locks held in the system:
4 locks held by kworker/u8:1/13:
#0: ffff888140473138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff888140473138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffff88801ff880d0 (&type->s_umount_key#70){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88805e846368 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
#0: ffffffff8d9ae9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9ae9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d9ae9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:12/3556:
#0: ffff88814d7a8138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88814d7a8138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc9000d0a7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000d0a7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffffffff8eca8b78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8eca8b78 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4194
6 locks held by kworker/u8:17/3808:
#0: ffff88801a2d4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88801a2d4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc9000d5e7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000d5e7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffffffff8ec9b740 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0 net/core/net_namespace.c:670
#3: ffff88806a3250d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#3: ffff88806a3250d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
#3: ffff88806a3250d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x117/0x3f0 net/devlink/core.c:506
#4: ffff88806a326300 (&devlink->lock_key#22){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
#4: ffff88806a326300 (&devlink->lock_key#22){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
#4: ffff88806a326300 (&devlink->lock_key#22){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x3f0 net/devlink/core.c:506
#5: ffffffff8d9b4430 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3816
2 locks held by getty/5561:
#0: ffff888034db20a0 (&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
4 locks held by syz.1.778/10982:
2 locks held by syz.1.778/10987:
#0: ffff88801ff88480 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499
#1: ffff88805e846738 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline]
#1: ffff88805e846738 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2873 [inline]
#1: ffff88805e846738 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2884 [inline]
#1: ffff88805e846738 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4888
2 locks held by syz-executor/12140:
#0: ffffffff8e422748 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e422748 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e422748 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8eca8b78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8eca8b78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8eca8b78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071
4 locks held by syz-executor/12185:
1 lock held by dhcpcd-run-hook/12459:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 de b5 ab fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ef c7 0e fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 5a f9 da 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167950 EFLAGS: 00000202
RAX: 1ffffffff3276100 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff993b1010 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff851582c0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff993b0d80 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881268d9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd961cf088 CR3: 000000000d7a8000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1961
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline]
serial8250_console_write+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3109 [inline]
console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3215
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3674
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246