INFO: task syz.7.143:6962 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kerne[ 320.871571][ T38] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.143 state:D stack:26648 pid:6962 tgid:6957 ppid:6421 task_flags:0x400040 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 include/linux/fs.h:1028 [inline]
open_last_lookups fs/namei.c:4580 [inline]
path_openat+0xb5e/0x38a0 fs/namei.c:4827
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
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: 0033:0x7ff1c645c799
RSP: 002b:00007ff1c468d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff1c66d6090 RCX: 00007ff1c645c799
RDX: 000000000000275a RSI: 0000200000000200 RDI: ffffffffffffff9c
RBP: 00007ff1c64f2c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff1c66d6128 R14: 00007ff1c66d6090 R15: 00007ffe1b7b79e8
INFO: task syz.7.143:6966 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.143 state:D stack:29024 pid:6966 tgid:6957 ppid:6421 task_flags:0x400040 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: 0033:0x7ff1c645b607
RSP: 002b:00007ff1c466be58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007ff1c466bee0 RCX: 00007ff1c645b607
RDX: 00000000000001ff RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 0000200000000140 R08: 00002000000000c0 R09: 0000000000000000
R10: 0000200000000140 R11: 0000000000000246 R12: 0000200000000040
R13: 00007ff1c466bea0 R14: 0000000000000000 R15: 0000000000000000
Showing all locks held in the system:
2 locks held by kworker/0:0/9:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:11/1021:
#0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc9000586fc40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc9000586fc40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
2 locks held by kworker/u8:12/1920:
1 lock held by syslogd/5149:
#0: ffff888029276218 (&ei->socket.wq.wait){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff888029276218 (&ei->socket.wq.wait){+.+.}-{3:3}, at: finish_wait+0xbe/0x1e0 kernel/sched/wait.c:394
3 locks held by klogd/5156:
2 locks held by getty/5563:
#0: ffff888037f6e0a0 (&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 udevd/5803:
1 lock held by udevd/5809:
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3252 [inline]
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3424 [inline]
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xd9f/0x2950 mm/page_alloc.c:3959
3 locks held by udevd/5821:
#0: ffff888038bee480 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline]
#0: ffff888038bee480 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff88803fda9c78 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#1: ffff88803fda9c78 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: shmem_file_write_iter+0x82/0x120 mm/shmem.c:3492
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3252 [inline]
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3424 [inline]
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xd9f/0x2950 mm/page_alloc.c:3959
5 locks held by udevd/5822:
1 lock held by syz-executor/6712:
7 locks held by syz.7.143/6958:
2 locks held by syz.7.143/6962:
#0: ffff88803d0e0480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
#1: ffff88806c001090 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#1: ffff88806c001090 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:4580 [inline]
#1: ffff88806c001090 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: path_openat+0xb5e/0x38a0 fs/namei.c:4827
2 locks held by syz.7.143/6966:
#0: ffff88803d0e0480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
#1: ffff88806c001090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline]
#1: ffff88806c001090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline]
#1: ffff88806c001090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline]
#1: ffff88806c001090 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4922
1 lock held by syz-executor/8076:
1 lock held by syz-executor/8527:
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: free_one_page+0x43/0x250 mm/page_alloc.c:1585
5 locks held by syz.0.347/8919:
#0: ffff88802ad7ea88 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:310
#1: ffff88803d0545f8 (sb_pagefaults#4){.+.+}-{0:0}, at: do_page_mkwrite+0x150/0x310 mm/memory.c:3589
#2: ffff8880616b84a8 (&ei->i_mmap_lock){++++}-{4:4}, at: btrfs_page_mkwrite+0x60e/0x1b10 fs/btrfs/file.c:1918
#3: ffff88803f1bc378 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x33/0x250 fs/btrfs/locking.c:146
#4: ffff88803f1bc128 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x33/0x250 fs/btrfs/locking.c:146
8 locks held by syz.0.347/8964:
3 locks held by syz.2.350/8946:
#0: ffff88801aada480 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline]
#0: ffff88801aada480 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff88805f602498 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#1: ffff88805f602498 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: shmem_file_write_iter+0x82/0x120 mm/shmem.c:3492
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3252 [inline]
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3424 [inline]
#2: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xd9f/0x2950 mm/page_alloc.c:3959
2 locks held by dhcpcd-run-hook/8971:
#0: ffff888039239d30 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline]
#0: ffff888039239d30 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
#0: ffff888039239d30 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501
#1: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#1: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue_buddy mm/page_alloc.c:3252 [inline]
#1: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3424 [inline]
#1: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: get_page_from_freelist+0xd9f/0x2950 mm/page_alloc.c:3959
=============================================
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 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 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 02/12/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 fe a3 94 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 7f b4 fa fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff332a600 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99953750 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff852fc2b0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff999534c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812633c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055663f2cd950 CR3: 000000003f35c000 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:3163 [inline]
console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
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