INFO: task syz.4.11:5833 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.11        state:D stack:28904 pid:5833  tgid:5829  ppid:5600   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7270
 __schedule_loop kernel/sched/core.c:7347 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7643
 rt_mutex_slowlock_block+0x55e/0x690 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 fdget_pos+0x252/0x320 fs/file.c:1259
 class_fd_pos_constructor include/linux/file.h:85 [inline]
 ksys_read+0x79/0x270 fs/read_write.c:707
 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: 0033:0x7f0b0777e159
RSP: 002b:00007f0b059b5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f0b07a06090 RCX: 00007f0b0777e159
RDX: 0000000000002020 RSI: 0000200000006180 RDI: 0000000000000003
RBP: 00007f0b07815024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0b07a06128 R14: 00007f0b07a06090 R15: 00007ffeb24e3678
 </TASK>

Showing all locks held in the system:
locks held by kthreadd/2: 2, last CPU#1: