INFO: task syz.5.4263:18122 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.4263 state:D stack:28136 pid:18122 tgid:18116 ppid:14390 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5584 [inline]
__schedule+0x1b47/0x5b40 kernel/sched/core.c:7387
__schedule_loop kernel/sched/core.c:7464 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7479
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7536
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821
bdev_open+0xde/0xd70 block/bdev.c:990
bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1104
bdev_file_open_by_path+0x1da/0x4a0 block/bdev.c:1127
btrfs_scan_one_device+0xa8/0x680 fs/btrfs/volumes.c:1500
btrfs_get_tree_super fs/btrfs/super.c:1867 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2097 [inline]
btrfs_get_tree+0x4ec/0x19f0 fs/btrfs/super.c:2131
vfs_get_tree+0x92/0x2a0 fs/super.c:1943
fc_mount fs/namespace.c:1278 [inline]
do_new_mount_fc fs/namespace.c:3885 [inline]
do_new_mount+0x325/0xb00 fs/namespace.c:3961
do_mount fs/namespace.c:4325 [inline]
__do_sys_mount fs/namespace.c:4540 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4517
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6c2759e199
RSP: 002b:00007f6c283ee028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6c27826090 RCX: 00007f6c2759e199
RDX: 0000200000000000 RSI: 0000200000000100 RDI: 0000200000000140
RBP: 00007f6c27635888 R08: 0000200000000980 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6c27826128 R14: 00007f6c27826090 R15: 00007ffe95950178
Showing all locks held in the system:
locks held by khungtaskd/35: 1, last CPU#1:
#0: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/1:2/993: 8, on CPU#1:
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90004e5fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004e5fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004e5fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90004e5fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88802b4ec1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802b4ec1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
#3: ffff8880536f91d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#3: ffff8880536f91d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#4: ffff888076f921a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff888076f921a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#5: ffff8880271c1a58 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#5: ffff8880271c1a58 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#6: ffff888051c79180 (&steam->registration_mutex){+.+.}-{4:4}, at: steam_register+0xc7/0x2ed0 drivers/hid/hid-steam.c:1376
#7: ffff888051c790f8 (&steam->report_mutex){+.+.}-{4:4}, at: steam_register+0x19b/0x2ed0 drivers/hid/hid-steam.c:1387
locks held by getty/5368: 2, on CPU#1:
#0: ffff8880371fe0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000323b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/1:5/5722: 3, on CPU#1:
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff888021ac1548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90004c47c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004c47c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004c47c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90004c47c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88802b5d91d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802b5d91d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
locks held by udevd/9524: 1, on CPU#1:
#0: ffff888028c3a350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by udevd/9527: 1, on CPU#0:
#0: ffff888028cde350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by udevd/10307: 1, on CPU#0:
#0: ffff888028dea350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by udevd/10333: 1, on CPU#0:
#0: ffff8880282a2350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by udevd/10679: 1, on CPU#0:
#0: ffff888028c3e350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by syz.5.4263/18122: 2, on CPU#0:
#0: ffffffff907eece0 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_super fs/btrfs/super.c:1861 [inline]
#0: ffffffff907eece0 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree_subvol fs/btrfs/super.c:2097 [inline]
#0: ffffffff907eece0 (uuid_mutex){+.+.}-{4:4}, at: btrfs_get_tree+0x4c1/0x19f0 fs/btrfs/super.c:2131
#1: ffff888028cde350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by syz-executor/18392: 4, last CPU#1:
#0: ffffffff90236110 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
#0: ffffffff90236110 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10a/0x470 kernel/fork.c:1594
#1: ffff88801c730f80 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:548 [inline]
#1: ffff88801c730f80 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
#2: ffff88804fd64080 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:538 [inline]
#2: ffff88804fd64080 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
#3: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:302
locks held by syz.2.4586/19715: 1, on CPU#1:
#0: ffff888028c3a350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by syz-executor/19915: 3, last CPU#0:
#0: ffff888022ab4460 (sb_writers#7){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:527
#1: ffff88807707be10 (&lockref->lock){+.+.}-{3:3}, at: fs_reclaim_acquire+0x7c/0x100 mm/page_alloc.c:4399
#2: ffff88807707b930 (&lockref->lock){+.+.}-{3:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#2: ffff88807707b930 (&lockref->lock){+.+.}-{3:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#2: ffff88807707b930 (&lockref->lock){+.+.}-{3:3}, at: prepend_path+0x4d/0x840 fs/d_path.c:164
locks held by syz.9.4829/20765: 2, last CPU#1:
#0: ffff888013f07180 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:586 [inline]
#0: ffff888013f07180 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
#1: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff9015a2e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:302
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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:377 [inline]
watchdog+0x1073/0x10f0 kernel/hung_task.c:598
kthread+0x38b/0x480 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 19915 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:debug_lockdep_rcu_enabled+0xd/0x40 kernel/rcu/update.c:321
Code: 8e 67 48 0f b9 3a 90 eb bc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d 53 36 bb 05 00 <74> 1d 83 3d 3a 64 bb 05 00 74 14 65 48 8b 0d 58 54 de 08 31 c0 83
RSP: 0018:ffffc900060f79f0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffc90000200000 RCX: 0000000000000000
RDX: ffff888051e9ddc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888051e9ddc0 R09: 0000000000000002
R10: 000000000000002f R11: 0000000000000000 R12: dffffc0000000000
R13: ffffc90000224aa0 R14: 1ffff92000044954 R15: ffff88802bbf73c0
FS: 0000555563681500(0000) GS:ffff88812342e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c383894 CR3: 000000003a12c000 CR4: 00000000003526f0
Call Trace:
__d_lookup_rcu+0xdc/0x4c0 fs/dcache.c:2584
lookup_fast+0xd2/0x5d0 fs/namei.c:1854
walk_component fs/namei.c:2307 [inline]
link_path_walk+0x712/0x1910 fs/namei.c:2685
path_parentat fs/namei.c:2889 [inline]
__filename_parentat+0x287/0x6f0 fs/namei.c:2913
filename_parentat fs/namei.c:2931 [inline]
filename_unlinkat+0x104/0x610 fs/namei.c:5730
__do_sys_unlink fs/namei.c:5796 [inline]
__se_sys_unlink+0x2e/0x140 fs/namei.c:5793
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc6e3f9d287
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffeb5d8b858 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000f73 RCX: 00007fc6e3f9d287
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffeb5d8b910
RBP: 00007ffeb5d8b910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffeb5d8ca00
R13: 00007fc6e4034ccb R14: 00005555636814e8 R15: 0000000000000007