syzbot

INFO: task syz.2.5786:27790 blocked for more than 187 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.5786      state:D stack:25024 pid:27790 tgid:27787 ppid:17761  task_flags:0x400040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5360 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7046 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7061
 __vma_enter_locked+0x277/0x380 mm/mmap_lock.c:64
 __vma_start_write+0x1e/0x120 mm/mmap_lock.c:87
 vma_start_write include/linux/mmap_lock.h:212 [inline]
 __split_vma+0x5b1/0xa00 mm/vma.c:545
 vms_gather_munmap_vmas+0x4c6/0x12e0 mm/vma.c:1380
 __mmap_setup mm/vma.c:2375 [inline]
 __mmap_region mm/vma.c:2669 [inline]
 mmap_region+0x724/0x1c70 mm/vma.c:2764
 do_mmap+0xc45/0x10d0 mm/mmap.c:558