INFO: task syz.0.6324:25747 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.6324 state:D stack:25928 pid:25747 tgid:25746 ppid:21658 task_flags:0x400140 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5360 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7046 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7061
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
device_lock include/linux/device.h:914 [inline]
usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414
do_dentry_open+0x953/0x13f0 fs/open.c:965
vfs_open+0x3b/0x340 fs/open.c:1095
do_open fs/namei.c:3895 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4054
do_filp_open+0x1fa/0x410 fs/namei.c:4081
do_sys_openat2+0x121/0x1c0 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1461
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f85d6b8d510
RSP: 002b:00007f85d7ad8b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000008041 RCX: 00007f85d6b8d510
RDX: 0000000000008041 RSI: 00007f85d7ad8c10 RDI: 00000000ffffff9c
RBP: 00007f85d7ad8c10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007f85d6dd6038 R14: 00007f85d6dd5fa0 R15: 00007fff65ddfc58
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:5/1005:
2 locks held by getty/5623:
#0: ffff88814d6fd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by sshd-session/5852:
#0: ffff888070825c68 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_read+0x125/0x1040 fs/pipe.c:282
1 lock held by syz-executor/5853:
4 locks held by udevd/5882:
#0: ffff88807861f1c8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20 fs/seq_file.c:182
#1: ffff88805c62cc88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
#2: ffff88805f22f0f8 (kn->active#24){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff88805f22f0f8 (kn->active#24){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
#3: ffff888060144198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
#3: ffff888060144198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/0:5/5936:
#0: ffff888143a98d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888143a98d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc900046bfba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc900046bfba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff888028758198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff888028758198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff888060144198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#3: ffff888060144198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
#4: ffff88805c3ff160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff88805c3ff160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
#5: ffffffff8e3e2a70 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xf0/0x2b0 kernel/umh.c:214
1 lock held by syz.0.6324/25747:
#0: ffff888028758198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#0: ffff888028758198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
1 lock held by syz.8.7240/28327:
#0: ffff888028758198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#0: ffff888028758198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
1 lock held by syz.4.7267/28398:
#0: ffff888028758198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#0: ffff888028758198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
3 locks held by syz-executor/28447:
1 lock held by syz.3.7284/28462:
#0: ffff88807e3a00a8 (&kvm->slots_lock){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:228 [inline]
#0: ffff88807e3a00a8 (&kvm->slots_lock){+.+.}-{4:4}, at: kvm_alloc_apic_access_page+0x2e/0x160 arch/x86/kvm/lapic.c:2753
10 locks held by syz.1.7285/28463:
#0: ffff88806121a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffff88806121a130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: tty_write_lock drivers/tty/tty_io.c:939 [inline]
#1: ffff88806121a130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: iterate_tty_write drivers/tty/tty_io.c:958 [inline]
#1: ffff88806121a130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write+0x211/0xa30 drivers/tty/tty_io.c:1081
#2: ffff88806121a2e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_write+0x1e0/0x1200 drivers/tty/n_tty.c:2360
#3: ffffc90003b73380 (&ldata->output_lock){+.+.}-{4:4}
, at: class_mutex_constructor include/linux/mutex.h:228 [inline]
, at: process_output_block drivers/tty/n_tty.c:517 [inline]
, at: n_tty_write+0x653/0x1200 drivers/tty/n_tty.c:2377
#4: ffffffff8e530860 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:669 [inline]
#4: ffffffff8e530860 (console_lock){+.+.}-{0:0}, at: do_con_write+0x116/0x5210 drivers/tty/vt/vt.c:3193
#5: ffff88814628f280 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_pan_display+0xbe/0xbd0 drivers/gpu/drm/drm_fb_helper.c:1441
#6: ffff8880250d0128 (&dev->master_mutex){+.+.}-{4:4}, at: drm_master_internal_acquire+0x20/0x80 drivers/gpu/drm/drm_auth.c:435
#7: ffff88814628f098 (&client->modeset_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_locked+0x4c/0x4d0 drivers/gpu/drm/drm_client_modeset.c:1204
#8: ffffc9000d1e7190 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_client_modeset_commit_atomic+0xda/0x760 drivers/gpu/drm/drm_client_modeset.c:1042
#9: ffffc9000d1e71b8 (crtc_ww_class_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_atomic+0xda/0x760 drivers/gpu/drm/drm_client_modeset.c:1042
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 5226 Comm: klogd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:lock_acquire+0x34/0x360 kernel/locking/lockdep.c:5828
Code: 55 41 54 53 48 83 ec 60 4d 89 ce 45 89 c7 41 89 cc 89 54 24 04 89 f3 49 89 fd 48 8b ac 24 98 00 00 00 65 48 8b 05 4c e4 49 11 <48> 89 44 24 58 0f 1f 44 00 00 65 8b 05 4f e4 49 11 83 f8 08 0f 83
RSP: 0018:ffffc900032072e0 EFLAGS: 00000282
RAX: 33ce3b80dd939000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e53c820
RBP: ffffffff81aafc9d R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90003207458 R11: ffffffff81ac8160 R12: 0000000000000002
R13: ffffffff8e53c820 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f7419afcc80(0000) GS:ffff8881258a7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000003060 CR3: 0000000070c48000 CR4: 00000000003526f0
Call Trace:
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1169 [inline]
is_module_text_address+0x39/0x1e0 kernel/module/main.c:3845
kernel_text_address+0x94/0xe0 kernel/extable.c:119
__kernel_text_address+0xd/0x40 kernel/extable.c:79
unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369
arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4770 [inline]
slab_alloc_node mm/slub.c:5068 [inline]
kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5120
__alloc_skb+0x112/0x2d0 net/core/skbuff.c:659
alloc_skb include/linux/skbuff.h:1377 [inline]
alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6667
sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2965
unix_dgram_sendmsg+0x461/0x1850 net/unix/af_unix.c:2153
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:729
__sys_sendto+0x3bd/0x520 net/socket.c:2231
__do_sys_sendto net/socket.c:2238 [inline]
__se_sys_sendto net/socket.c:2234 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2234
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7419c4c407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffcf3701cc0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f7419afcc80 RCX: 00007f7419c4c407
RDX: 000000000000004f RSI: 00007ffcf3701e00 RDI: 0000000000000003
RBP: 00007ffcf3702230 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffcf3702248
R13: 00007ffcf3701e00 R14: 0000000000000034 R15: 00007ffcf3701e00