INFO: task syz.0.1310:10292 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1310 state:D stack:27944 pid:10292 tgid:10286 ppid:5601 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5526 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7277
__schedule_loop kernel/sched/core.c:7354 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7369
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7426
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccb/0x1bd0 kernel/locking/mutex.c:821
write_threads+0x288/0x600 fs/nfsd/nfsctl.c:436
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:114
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8efc59e159
RSP: 002b:00007f8efd3f5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8efc826090 RCX: 00007f8efc59e159
RDX: 0000000000000002 RSI: 0000200000000900 RDI: 0000000000000004
RBP: 00007f8efc63503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8efc826128 R14: 00007f8efc826090 R15: 00007fff74438508
Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#1:
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by kworker/u8:9/1272: 3, last CPU#1:
#0: ffff888021a95940 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc90005307d08 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
#2: ffff8880300d20e8 (&type->s_umount_key#75){++++}-{4:4}, at: super_trylock_shared+0x21/0xf0 fs/super.c:674
locks held by syz-executor/5600: 2, last CPU#1:
#0: ffff88807c8f0460 (sb_writers#6){.+.+}-{0:0}, at: filename_unlinkat+0x1ad/0x730 fs/namei.c:5696
#1: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xbd/0x2090 arch/x86/kernel/unwind_orc.c:495
locks held by kworker/0:5/5728: 2, last CPU#0:
#0: ffff88801c059d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc9000496fd08 ((gc_work).work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
locks held by kworker/0:2H/5991: 7, last CPU#0:
#0: ffff88801c05ad40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc90005257d08 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
#2: ffff8880b843bf60 (&rq->__lock){-.-.}-{2:2}, at: class_spinlock_irqsave_constructor include/linux/spinlock.h:642 [inline]
#2: ffff8880b843bf60 (&rq->__lock){-.-.}-{2:2}, at: snd_timer_interrupt sound/core/timer.c:906 [inline]
#2: ffff8880b843bf60 (&rq->__lock){-.-.}-{2:2}, at: snd_timer_interrupt+0xb2/0x1090 sound/core/timer.c:892
#3: ffff8880423f7c70 (&runtime->sleep){....}-{3:3}, at: __wake_up_common_lock kernel/sched/wait.c:125 [inline]
#3: ffff8880423f7c70 (&runtime->sleep){....}-{3:3}, at: __wake_up+0x1c/0x60 kernel/sched/wait.c:147
#4: ffff88804a978a98 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:594 [inline]
#4: ffff88804a978a98 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xbd/0x1c90 kernel/sched/core.c:4308
#5: ffff8880b843bf60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:685 [inline]
#5: ffff8880b843bf60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:669
#6: ffff8880b8424568 (psi_seq){-.-.}-{0:0}, at: psi_enqueue kernel/sched/stats.h:159 [inline]
#6: ffff8880b8424568 (psi_seq){-.-.}-{0:0}, at: enqueue_task+0x1dc/0x4f0 kernel/sched/core.c:2196
locks held by kworker/u8:28/6053: 3, last CPU#1:
#0: ffff88801c094140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
#1: ffffc90005647d08 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372
#2: ffff888046b007a0 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6905 [inline]
#2: ffff888046b007a0 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: cfg80211_wiphy_work+0x92/0x550 net/wireless/core.c:526
locks held by kworker/u8:36/7345: 1, last CPU#1:
#0: ffff888078f90140 ((wq_completion)bond0#7){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371
locks held by syz.0.1310/10288: 3, on CPU#0:
#0: ffff888023331270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff8880576a6460 (sb_writers#24){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f289500 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
locks held by syz.0.1310/10292: 3, on CPU#1:
#0: ffff88801de87430 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff8880576a6460 (sb_writers#24){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f289500 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x288/0x600 fs/nfsd/nfsctl.c:436
locks held by syz.1.1839/12185: 1, last CPU#1:
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xbd/0x2090 arch/x86/kernel/unwind_orc.c:495
locks held by syz.2.1841/12181: 3, last CPU#1:
#0: ffff8880786b9b30 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff888077a5c460 (sb_writers#3){.+.+}-{0:0}, at: do_writev+0x13e/0x340 fs/read_write.c:1104
#2: ffff8880262a60e8 (&type->s_umount_key#58){++++}-{4:4}, at: super_trylock_shared fs/super.c:674 [inline]
#2: ffff8880262a60e8 (&type->s_umount_key#58){++++}-{4:4}, at: super_cache_scan+0x9b/0x550 fs/super.c:200
locks held by syz.3.1842/12182: 2, last CPU#1:
#0: ffff8880300d2460 (sb_writers#14){.+.+}-{0:0}, at: ksys_write+0x1f8/0x250 fs/read_write.c:739
#1: ffff888058635240 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#1: ffff888058635240 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: fuse_cache_write_iter fs/fuse/file.c:1510 [inline]
#1: ffff888058635240 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: fuse_file_write_iter+0x2ea/0x960 fs/fuse/file.c:1868
locks held by syz.3.1842/12183: 1, on CPU#1:
#0: ffff888058635240 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#0: ffff888058635240 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: fuse_fsync+0x135/0x330 fs/fuse/file.c:550
locks held by syz.5.1844/12190: 1, last CPU#1:
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8edec4a0 (rcu_read_lock){....}-{1:3}, at: __fget_files+0x34/0x3d0 fs/file.c:1098
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 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: 12189 Comm: syz.5.1844 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026
RIP: 0010:lock_class_cache_is_valid kernel/locking/lockdep.c:978 [inline]
RIP: 0010:__lock_acquire+0xdb/0x1f40 kernel/locking/lockdep.c:5155
Code: 92 c2 08 d0 0f 85 8c 01 00 00 48 81 fd a0 3d aa 96 0f 83 7f 01 00 00 48 ba 29 5c 8f c2 f5 28 5c 8f 48 89 e8 48 2d a0 3d 91 96 <48> c1 f8 03 48 0f af c2 48 0f a3 05 55 08 aa 14 0f 83 56 01 00 00
RSP: 0018:ffffc9000305f7c8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 8f5c28f5c28f5c29 RSI: 0000000000000000 RDI: ffffffff9bc19868
RBP: ffffffff96913da0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88804a978000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff9bc19868
FS: 00007f29f36376c0(0000) GS:ffff888123b59000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000d000 CR3: 0000000035f9a000 CR4: 00000000003526f0
Call Trace:
lock_acquire kernel/locking/lockdep.c:5942 [inline]
lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:181
debug_object_free+0x13c/0x550 lib/debugobjects.c:1025
schedule_timeout+0x137/0x280 kernel/time/sleep_timeout.c:103
snd_rawmidi_write+0x492/0xc60 sound/core/rawmidi.c:1619
do_loop_readv_writev fs/read_write.c:851 [inline]
do_loop_readv_writev fs/read_write.c:836 [inline]
vfs_writev+0x5ed/0xdd0 fs/read_write.c:1060
do_writev+0x28a/0x340 fs/read_write.c:1104
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f29f279e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f29f3637028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f29f2a25fa0 RCX: 00007f29f279e159
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000009
RBP: 00007f29f283503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f29f2a26038 R14: 00007f29f2a25fa0 R15: 00007ffc7b251a18