INFO: task syz.4.9845:32156 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.4.9845 state:D stack:27432 pid:32156 tgid:32155 ppid:19114 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5526 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7276
__schedule_loop kernel/sched/core.c:7353 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7368
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7425
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:114
vfs_write+0x296/0xba0 fs/read_write.c:685
ksys_write+0x150/0x270 fs/read_write.c:739
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: 0033:0x7f07af59e159
RSP: 002b:00007f07b0519028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f07af825fa0 RCX: 00007f07af59e159
RDX: 0000000000000005 RSI: 0000200000000b00 RDI: 0000000000000003
RBP: 00007f07af63503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f07af826038 R14: 00007f07af825fa0 R15: 00007ffe443b04d8
Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#0:
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5368: 2, on CPU#0:
#0: ffff888034eab0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/5625: 2, on CPU#0:
#0: ffff888031a660e8 (&type->s_umount_key#100){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff888031a660e8 (&type->s_umount_key#100){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff888031a660e8 (&type->s_umount_key#100){+.+.}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8f09f500 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:582
locks held by syz.3.9829/32114: 3, on CPU#0:
#0: ffff88802af147f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff88807f540460 (sb_writers#44){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88807f540460 (sb_writers#44){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8f09f500 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:867
locks held by syz.4.9845/32156: 3, on CPU#0:
#0: ffff8880344969b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888035a46460 (sb_writers#44){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888035a46460 (sb_writers#44){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8f09f500 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
locks held by syz.5.10742/2668: 2, last CPU#0:
#0: ffff88801c2f2460 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#0: ffff88801c2f2460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#1: ffff88804c9fb2c8 (&sb->s_type->i_mutex_key#15){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#1: ffff88804c9fb2c8 (&sb->s_type->i_mutex_key#15){++++}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3430
locks held by syz.8.10751/2700: 1, last CPU#0:
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock_dont_migrate include/linux/rcupdate.h:991 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: bpf_test_timer_enter+0xf9/0x260 net/bpf/test_run.c:39
locks held by rm/2702: 2, last CPU#0:
#0: ffff88807fe21078 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:544 [inline]
#0: ffff88807fe21078 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2d8/0x9f0 mm/mmap.c:1323
#1: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz-executor/2706: 2, last CPU#0:
#0: ffff888034220460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
#1: ffff88802d190288 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline]
#1: ffff88802d190288 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2918 [inline]
#1: ffff88802d190288 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2942 [inline]
#1: ffff88802d190288 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:5092
=============================================
NMI backtrace for cpu 0
CPU: 0 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 08/05/2026
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:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
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