INFO: task syz.5.2345:13087 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.5.2345 state:D stack:26920 pid:13087 tgid:13087 ppid:11330 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
__mutex_lock_common kernel/locking/mutex.c:680 [inline]
__mutex_lock+0x7e6/0x1360 kernel/locking/mutex.c:764
bdev_release+0x1a9/0x650 block/bdev.c:1128
blkdev_release+0x15/0x20 block/fops.c:699
__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: 0033:0x7f936ff8e9a9
RSP: 002b:00007fff97f3d6f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f93701b7ba0 RCX: 00007f936ff8e9a9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f93701b7ba0 R08: 000000000000016c R09: 0000001597f3d9ef
R10: 00000000003ffc70 R11: 0000000000000246 R12: 0000000000067977
R13: 00007f93701b6160 R14: ffffffffffffffff R15: 00007fff97f3d810
Showing all locks held in the system:
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
2 locks held by getty/5610:
#0: ffff8880305320a0 (&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
6 locks held by kworker/0:6/5981:
1 lock held by udevd/7961:
#0: ffff888025b13358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
4 locks held by udevd/7985:
#0: ffff8880420a7d58 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:182
#1: ffff888066403488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154
#2: ffff88805e1acd28 (kn->active#24){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:155
#3: ffff88803360c198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:916 [inline]
#3: ffff88803360c198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
2 locks held by syz-executor/12627:
1 lock held by syz.5.2345/13087:
#0: ffff888025b13358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1a9/0x650 block/bdev.c:1128
1 lock held by syz.4.3292/16272:
#0: ffffffff8e543200 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815
1 lock held by syz.8.3294/16279:
#0: ffffffff8e543200 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815
1 lock held by syz.8.3294/16280:
#0: ffffffff8e543200 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815
=============================================
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: 16281 Comm: syz.8.3294 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:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210
Code: 89 fb e8 23 00 00 00 48 8b 3d e4 43 29 0c 48 89 de 5b e9 b3 84 58 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 50 e7 92 65 8b 15 08 4f
RSP: 0018:ffffc90000007e20 EFLAGS: 00000046
RAX: 000000000001ad24 RBX: 7fffffffffffffff RCX: ffff88802a250000
RDX: 0000000000010000 RSI: 7fffffffffffffff RDI: 00000087bbf4a712
RBP: ffff8880b8627ce8 R08: 0000000000000000 R09: ffffffff81aeb970
R10: dffffc0000000000 R11: ffffffff8167f930 R12: 00000087a4eae405
R13: 00000087bbf4a712 R14: ffff8880b8627ce8 R15: 000000000001ad24
FS: 0000000000000000(0000) GS:ffff8881257ab000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c37d1d2 CR3: 0000000074896000 CR4: 00000000003526f0
Call Trace:
ktime_get_update_offsets_now+0x3ab/0x3d0 kernel/time/timekeeping.c:2569
hrtimer_update_base kernel/time/hrtimer.c:640 [inline]
hrtimer_interrupt+0x132/0xaa0 kernel/time/hrtimer.c:1869
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__memcg_slab_free_hook+0x61/0x3d0 mm/memcontrol.c:-1
Code: 84 c0 0f 85 54 03 00 00 85 c9 0f 8e 38 03 00 00 41 8b 04 24 4c 8d 65 20 ba f8 ff ff ff 29 c2 89 54 24 08 83 c0 08 89 44 24 0c <48> 83 c5 08 89 c8 48 c1 e0 03 48 89 44 24 48 45 31 f6 48 c7 c0 40
RSP: 0018:ffffc9000be7f550 EFLAGS: 00000206
RAX: 0000000000000078 RBX: ffffc9000be7f5f0 RCX: 0000000000000001
RDX: 00000000ffffff88 RSI: ffffea0000ceb000 RDI: ffff88801bed5280
RBP: ffff88801bed5280 R08: ffff88805d12b800 R09: 1ffffffff1fc79e6
R10: dffffc0000000000 R11: fffffbfff1fc79e7 R12: ffff88801bed52a0
R13: ffff88805d12b800 R14: ffff88801bed5280 R15: ffffea0000ceb000
memcg_slab_free_hook mm/slub.c:2242 [inline]
slab_free mm/slub.c:4677 [inline]
kmem_cache_free+0x223/0x400 mm/slub.c:4782
anon_vma_chain_free mm/rmap.c:147 [inline]
unlink_anon_vmas+0x2cc/0x670 mm/rmap.c:421
free_pgtables+0x587/0xaf0 mm/memory.c:398
exit_mmap+0x444/0xb50 mm/mmap.c:1291
__mmput+0x118/0x430 kernel/fork.c:1124
exit_mm+0x1da/0x2c0 kernel/exit.c:581
do_exit+0x648/0x2300 kernel/exit.c:947
do_group_exit+0x21c/0x2d0 kernel/exit.c:1100
get_signal+0x1286/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
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: 0033:0x7efc18d8e9a9
Code: Unable to access opcode bytes at 0x7efc18d8e97f.
RSP: 002b:00007efc19b240e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007efc18fb6168 RCX: 00007efc18d8e9a9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efc18fb6168
RBP: 00007efc18fb6160 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007efc18fb616c
R13: 0000000000000000 R14: 00007fffa99b8b90 R15: 00007fffa99b8c78