INFO: task syz.0.1116:9463 blocked for more than 143 seconds.
Not tainted 6.16.0-rc6-next-20250718-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1116 state:D stack:26584 pid:9463 tgid:9463 ppid:5843 task_flags:0x400040 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5351 [inline]
__schedule+0x1737/0x4d30 kernel/sched/core.c:6954
__schedule_loop kernel/sched/core.c:7036 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7051
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7108
rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1187
__down_write_common kernel/locking/rwsem.c:1319 [inline]
__down_write kernel/locking/rwsem.c:1328 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1593
mmap_write_lock include/linux/mmap_lock.h:356 [inline]
userfaultfd_release_all+0x15a/0x5e0 mm/userfaultfd.c:2055
userfaultfd_release+0xe7/0x1b0 fs/userfaultfd.c:868
__fput+0x449/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:208 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbc8ef8e9a9
RSP: 002b:00007fff175b8258 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fbc8f1b7ba0 RCX: 00007fbc8ef8e9a9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fbc8f1b7ba0 R08: 000000000000013c R09: 0000000a175b854f
R10: 00007fbc8f1b7ac0 R11: 0000000000000246 R12: 0000000000044fc5
R13: 00007fff175b8350 R14: ffffffffffffffff R15: 00007fff175b8370
Showing all locks held in the system:
6 locks held by kworker/0:1/10:
#0: ffff88801e282548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801e282548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc900000f7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc900000f7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888028229198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff888028229198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff888145757518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3251 [inline]
#3: ffff888145757518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5463 [inline]
#3: ffff888145757518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#3: ffff888145757518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#3: ffff888145757518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20 drivers/usb/core/hub.c:5952
#4: ffff888027221668 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
#4: ffff888027221668 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#4: ffff888027221668 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#4: ffff888027221668 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20 drivers/usb/core/hub.c:5952
#5: ffffffff8f1f8090 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x163/0x1750 drivers/usb/core/hub.c:3066
1 lock held by khungtaskd/31:
#0: ffffffff8e53d8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e53d8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e53d8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
5 locks held by kworker/1:2/851:
#0: ffff88801e282548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801e282548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90003437bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90003437bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff88814572b198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff88814572b198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff888028dfe198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#3: ffff888028dfe198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
#4: ffff88805fd3f160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#4: ffff88805fd3f160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
2 locks held by getty/5608:
#0: ffff88814df560a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
5 locks held by kworker/1:3/5874:
#0: ffff88801e282548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801e282548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90004447bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90004447bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff8880281bb198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff8880281bb198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff888026dec198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#3: ffff888026dec198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
#4:
ffff88805f90e160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
ffff88805f90e160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
1 lock held by udevd/5883:
#0: ffff8880b8639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636
1 lock held by udevd/6101:
1 lock held by syz.0.1116/9463:
#0: ffff888079b96d60 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:356 [inline]
#0: ffff888079b96d60 (&mm->mmap_lock){++++}-{4:4}, at: userfaultfd_release_all+0x15a/0x5e0 mm/userfaultfd.c:2055
1 lock held by syz.0.1116/9464:
2 locks held by syz.2.1748/11849:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc6-next-20250718-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:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
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: 11849 Comm: syz.2.1748 Not tainted 6.16.0-rc6-next-20250718-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x5a/0xb0 kernel/rcu/tree.c:751
Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 dc 99 7c 00 48 c7 c3 58 7f e8 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 34 8b 03 65 ff 0d c9 98 40 11 74 11 83 e0 04 c1 e8 02 5b
RSP: 0018:ffffc9001165f198 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: ffff8880b8632f58 RCX: b33522875949be00
RDX: 0000000000000000 RSI: ffffffff8c04d3e0 RDI: ffffffff8c04d3a0
RBP: ffffffff81730195 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc9001165f378 R11: ffffffff81ac9660 R12: 0000000000000002
R13: ffffffff8e53d8a0 R14: ffffffff8de93d10 R15: dffffc0000000000
FS: 00007f06622706c0(0000) GS:ffff8881257ab000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ab4bad9130 CR3: 00000000582fe000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000004 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x5f/0x360 kernel/locking/lockdep.c:5834
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:1155 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2417 [inline]
slab_free mm/slub.c:4680 [inline]
kmem_cache_free+0x18f/0x400 mm/slub.c:4782
free_buffer_head+0x55/0x220 fs/buffer.c:3041
try_to_free_buffers+0x232/0x2d0 fs/buffer.c:2982
mapping_evict_folio+0x216/0x2e0 mm/truncate.c:311
mapping_try_invalidate+0x1c2/0x410 mm/truncate.c:535
bdev_disk_changed+0x203/0x14b0 block/partitions/core.c:657
blkdev_get_whole+0x380/0x510 block/bdev.c:748
bdev_open+0x31e/0xd30 block/bdev.c:957
bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1059
disk_scan_partitions+0x1c1/0x2c0 block/genhd.c:387
blkdev_ioctl+0x4ef/0x6d0 block/ioctl.c:704
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:598 [inline]
__se_sys_ioctl+0xf9/0x170 fs/ioctl.c:584
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f066138e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0662270038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f06615b5fa0 RCX: 00007f066138e9a9
RDX: 0000000000000000 RSI: 000000000000125f RDI: 0000000000000006
RBP: 00007f0661410d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f06615b5fa0 R15: 00007fff778b83e8