INFO: task syz.6.3444:16932 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.3444 state:D stack:25160 pid:16932 tgid:16932 ppid:15357 task_flags:0x400040 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
request_wait_answer fs/fuse/dev.c:585 [inline]
__fuse_request_send fs/fuse/dev.c:599 [inline]
__fuse_simple_request+0x11d2/0x1bb0 fs/fuse/dev.c:693
fuse_simple_request fs/fuse/fuse_i.h:1250 [inline]
fuse_flush+0x5dd/0x810 fs/fuse/file.c:482
filp_flush+0xc0/0x190 fs/open.c:1549
filp_close+0x1d/0x40 fs/open.c:1562
__range_close fs/file.c:767 [inline]
__do_sys_close_range fs/file.c:826 [inline]
__se_sys_close_range+0x35c/0x650 fs/file.c:790
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb94bb1efc9
RSP: 002b:00007fff43bd4cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 000000000012042a RCX: 00007fb94bb1efc9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fb94bd77da0 R08: 0000000000000001 R09: 0000001543bd4fef
R10: 0000001b31920000 R11: 0000000000000246 R12: 00007fb94bd7609c
R13: 00007fb94bd76090 R14: ffffffffffffffff R15: 00007fff43bd4e10
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d5aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5aa4c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/1:2/2003:
2 locks held by getty/5558:
#0: ffff88823bf348a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz.4.3776/18079:
#0: ffff88805cd409b8 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#0: ffff88805cd409b8 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: fuse_cache_write_iter fs/fuse/file.c:1437 [inline]
#0: ffff88805cd409b8 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: fuse_file_write_iter+0xa8e/0x10c0 fs/fuse/file.c:1783
3 locks held by syz-executor/18257:
1 lock held by syz.7.3885/18433:
4 locks held by syz.5.3890/18447:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 18433 Comm: syz.7.3885 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:-1 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:233 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3820 [inline]
RIP: 0010:validate_chain+0x4e/0x2140 kernel/locking/lockdep.c:3876
Code: 8b 46 20 89 c1 81 e1 00 80 04 00 81 f9 00 00 04 00 0f 85 61 02 00 00 41 89 d4 49 89 f6 25 ff 1f 00 00 48 0f a3 05 c2 af 0d 11 <48> 89 3c 24 72 36 83 3d 75 3f 11 17 00 75 2d 90 e8 dd c6 d9 02 85
RSP: 0018:ffffc90009c579c0 EFLAGS: 00000003
RAX: 00000000000002da RBX: 0000000000000000 RCX: 0000000000040000
RDX: 0000000000000001 RSI: ffff88802b5ba960 RDI: ffff88802b5b9e00
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff82094ea0
R10: dffffc0000000000 R11: ffffed1005e1dd5d R12: 0000000000000001
R13: ffff88802b5ba960 R14: ffff88802b5ba960 R15: 412aadc2cd62c3ad
FS: 00007f8681ea66c0(0000) GS:ffff888126dfc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000007a2030 CR3: 0000000055398000 CR4: 00000000003526f0
Call Trace:
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__might_fault+0xcc/0x130 mm/memory.c:7081
do_recvmmsg+0x336/0x770 net/socket.c:2993
__sys_recvmmsg net/socket.c:3061 [inline]
__do_sys_recvmmsg net/socket.c:3084 [inline]
__se_sys_recvmmsg net/socket.c:3077 [inline]
__x64_sys_recvmmsg+0x190/0x240 net/socket.c:3077
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8683c3efc9
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:00007f8681ea6038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f8683e95fa0 RCX: 00007f8683c3efc9
RDX: 03fffffffffffdfc RSI: 00002000000099c0 RDI: 0000000000000003
RBP: 00007f8683cc1f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000010002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8683e96038 R14: 00007f8683e95fa0 R15: 00007ffe00da17e8