syzbot

INFO: task syz.6.545:7088 blocked for more than 144 seconds.
      Not tainted 6.1.131-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.545       state:D stack:25864 pid:7088  ppid:6313   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 request_wait_answer fs/fuse/dev.c:407 [inline]
 __fuse_request_send fs/fuse/dev.c:426 [inline]
 fuse_simple_request+0x115a/0x1b40 fs/fuse/dev.c:513
 fuse_flush+0x694/0x950 fs/fuse/file.c:521
 filp_close+0xae/0x150 fs/open.c:1431
 __range_close fs/file.c:697 [inline]
 __close_range+0x597/0x7d0 fs/file.c:747
 __do_sys_close_range fs/open.c:1476 [inline]
 __se_sys_close_range fs/open.c:1473 [inline]
 __x64_sys_close_range+0x76/0x80 fs/open.c:1473
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbadcb8d169
RSP: 002b:00007fffebe50ea8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007fbadcda7ba0 RCX: 00007fbadcb8d169
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fbadcda7ba0 R08: 00000000000000a0 R09: 00000009ebe5119f
R10: 00007fbadcda7ac0 R11: 0000000000000246 R12: 0000000000053078
R13: 00007fffebe50fa0 R14: ffffffffffffffff R15: 00007fffebe50fc0
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32e890 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d32f090 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510
2 locks held by getty/4011:
 #0: ffff8880310a4098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x54a/0x1620 drivers/tty/n_tty.c:2198
3 locks held by kworker/u4:13/4595:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1ca/0x430 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3611 Comm: klogd Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:is_idle_task include/linux/sched.h:1922 [inline]
RIP: 0010:__might_resched+0x20d/0x780 kernel/sched/core.c:9922
Code: 89 de 48 ba 00 00 00 00 00 fc ff df f6 84 24 a1 00 00 00 02 44 8b 64 24 1c 74 4d 4c 8d 66 2c 4c 89 e0 48 c1 e8 03 0f b6 04 10 <84> c0 0f 85 75 04 00 00 41 f6 04 24 02 44 8b 64 24 1c 75 2a 4c 8d
RSP: 0018:ffffc900032a77a0 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: 1ffff92000654f08 RCX: ffff88807d52bb80
RDX: dffffc0000000000 RSI: ffff88807d52bb80 RDI: ffffc900032a7840
RBP: ffffc900032a78c0 R08: ffffffff81cdb2ac R09: fffff9400021ccc1
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88807d52bbac
R13: ffff88807d52bfbc R14: 0000000000000276 R15: 1ffff92000654efc
FS:  00007f1658956380(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f3d377d38 CR3: 0000000018bc5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __might_fault+0x69/0x110 mm/memory.c:5850
 _copy_from_iter+0xfa/0xff0 lib/iov_iter.c:630
 copy_from_iter include/linux/uio.h:187 [inline]
 skb_copy_datagram_from_iter+0xef/0x6b0 net/core/datagram.c:561
 unix_dgram_sendmsg+0x96c/0x2060 net/unix/af_unix.c:1931
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x480/0x600 net/socket.c:2153
 __do_sys_sendto net/socket.c:2165 [inline]
 __se_sys_sendto net/socket.c:2161 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2161
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1658ab89b5
Code: 8b 44 24 08 48 83 c4 28 48 98 c3 48 98 c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 26 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 7a 48 8b 15 44 c4 0c 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffdf2921368 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1658ab89b5
RDX: 000000000000005e RSI: 0000556419ddd790 RDI: 0000000000000003
RBP: 0000556419dd6910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013
R13: 00007f1658c46212 R14: 00007ffdf2921468 R15: 0000000000000000
 </TASK>