INFO: task syz.7.1674:16243 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
task:syz.7.1674 state:D stack:25712 pid:16243 tgid:16238 ppid:9497 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
sync_bdevs+0x276/0x470 block/bdev.c:1370
ksys_sync fs/sync.c:105 [inline]
__ia32_sys_sync+0xc5/0x120 fs/sync.c:111
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f21fc42de99
RSP: 002b:00007f21fa665028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f21fc6b6090 RCX: 00007f21fc42de99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f21fc6b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f21fc6b6128 R14: 00007f21fc6b6090 R15: 00007ffc39fb1fd8
Showing all locks held in the system:
locks held by khungtaskd/38: 1, last CPU#0:
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6835
locks held by getty/5348: 2, on CPU#0:
#0: ffff8880364fd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900044cb2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/1:5/5699: 9, last CPU#1:
#0: ffff88801b30a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff88801b30a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff88801b30a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc900064dfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc900064dfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc900064dfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffff88802a0a4210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802a0a4210 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4cf0 drivers/usb/core/hub.c:5899
#3: ffff888037cb6210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#3: ffff888037cb6210 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#4: ffff88803e8321d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff88803e8321d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#5: ffffffff8f72a038 (register_mutex#6){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#5: ffffffff8f72a038 (register_mutex#6){+.+.}-{4:4}, at: usb_audio_probe+0x5e6/0x2290 sound/usb/card.c:985
#6: ffffffff8f705cf8 (sound_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#6: ffffffff8f705cf8 (sound_mutex){+.+.}-{4:4}, at: snd_register_device+0x17c/0x510 sound/core/sound.c:275
#7: ffffffff8e588b58 (sysfs_symlink_target_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#7: ffffffff8e588b58 (sysfs_symlink_target_lock){+.+.}-{3:3}, at: sysfs_do_create_link_sd+0x36/0x110 fs/sysfs/symlink.c:34
#8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
locks held by udevd/8262: 1, on CPU#1:
#0: ffff88802742e4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:991
locks held by udevd/10382: 4, on CPU#0:
#0: ffff88803af3e720 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa5/0xcb0 fs/seq_file.c:183
#1: ffff888062820878 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165
#2: ffff8880425570f8 (kn->active#30){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff8880425570f8 (kn->active#30){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:166
#3: ffff888037cb6210 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1109 [inline]
#3: ffff888037cb6210 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
locks held by kworker/u8:53/15320: 8, last CPU#0:
#0: ffff88801bee4938 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff88801bee4938 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff88801bee4938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc90005147c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc90005147c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc90005147c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffff888034aee0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x23/0xf0 fs/super.c:688
#3: ffff8880356f0cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
#3: ffff8880356f0cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1876 [inline]
#3: ffff8880356f0cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x205/0x3b0 fs/ext4/inode.c:3042
#4: ffff888034aeabb0 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fc3/0x2210 fs/jbd2/transaction.c:444
#5: ffff88804059e148 (&ei->i_data_sem#2){++++}-{4:4}, at: ext4_map_blocks+0x7cc/0x1240 fs/ext4/inode.c:823
#6: ffff888034aec158 (&bgl->locks[i].lock){+.+.}-{3:3}, at: ext4_try_lock_group fs/ext4/ext4.h:3664 [inline]
#6: ffff888034aec158 (&bgl->locks[i].lock){+.+.}-{3:3}, at: ext4_lock_group fs/ext4/ext4.h:3676 [inline]
#6: ffff888034aec158 (&bgl->locks[i].lock){+.+.}-{3:3}, at: ext4_mb_mark_context+0x21f/0xec0 fs/ext4/mballoc.c:4130
#7: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#7: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#7: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_trylock kernel/locking/spinlock_rt.c:127 [inline]
#7: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_trylock+0x10c/0x2b0 kernel/locking/spinlock_rt.c:135
locks held by syz.7.1674/16243: 1, on CPU#1:
#0: ffff88802742e4c8 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x276/0x470 block/bdev.c:1370
locks held by syz.0.1798/16862: 1, on CPU#0:
#0: ffff88802742e4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:991
locks held by syz.5.2243/19101: 3, last CPU#1:
#0: ffff8880688d0510 (sb_writers#5){.+.+}-{0:0}, at: do_coredump fs/coredump.c:1126 [inline]
#0: ffff8880688d0510 (sb_writers#5){.+.+}-{0:0}, at: vfs_coredump+0x376c/0x4530 fs/coredump.c:1195
#1: ffff88803ebaf030 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:609 [inline]
#1: ffff88803ebaf030 (&mm->mmap_lock){++++}-{4:4}, at: dump_user_range+0x1c5/0x12c0 fs/coredump.c:1349
#2: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#2: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#2: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: mt_find+0x186/0x630 lib/maple_tree.c:6405
locks held by syz.5.2246/19124: 1, last CPU#0:
#0: ffff88803a252cb0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
#0: ffff88803a252cb0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1284
locks held by syz.4.2250/19121: 4, last CPU#1:
#0: ffff8880388791b0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:619 [inline]
#0: ffff8880388791b0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
#0: ffff8880388791b0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501
#1: ffff888034aee688 (sb_pagefaults){.+.+}-{0:0}, at: percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
#1: ffff888034aee688 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs/super.h:19 [inline]
#1: ffff888034aee688 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline]
#1: ffff888034aee688 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x203/0x1150 fs/ext4/inode.c:6804
#2: ffff888034aeabb0 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fc3/0x2210 fs/jbd2/transaction.c:444
#3: ffffffff8e011928 (bit_wait_table + i){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#3: ffffffff8e011928 (bit_wait_table + i){+.+.}-{3:3}, at: prepare_to_wait+0x44/0x200 kernel/sched/wait.c:253
locks held by syz.6.2251/19125: 4, last CPU#0:
#0: ffff888038878430 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
#0: ffff888038878430 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1284
#1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#2: ffff8880213cddd8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff8880213cddd8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/legacy 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:delay_tsc+0x5b/0xc0 arch/x86/lib/delay.c:79
Code: 90 49 89 d7 49 c1 e7 20 49 09 c7 4d 29 f7 49 39 df 73 53 bf 01 00 00 00 e8 92 37 45 f6 65 8b 05 1b 20 74 07 85 c0 74 1c f3 90 01 00 00 00 e8 db 35 45 f6 e8 f6 80 01 00 39 c5 75 0e 0f 01 f9
RSP: 0018:ffffc90000167a28 EFLAGS: 00000286
RAX: 0000000080000000 RBX: 0000000000000899 RCX: 0000000000000000
RDX: 00000000000001a5 RSI: ffffffff8bcbd060 RDI: 00000000ffffffff
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8b4ebfc0 R12: 1ffffffff340f102
R13: 00000000ffffffff R14: 000001a52b4da938 R15: 000000000000018c
FS: 0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556b19e4e8 CR3: 000000003f78e000 CR4: 00000000003526f0
Call Trace:
udelay include/asm-generic/delay.h:62 [inline]
wait_for_lsr+0x14d/0x300 drivers/tty/serial/8250/8250_port.c:1988
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3235 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3300 [inline]
serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3385
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x667/0xb90 kernel/printk/printk.c:3268
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3719
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