syzbot

INFO: task syz-executor.1:19947 can't die for more than 143 seconds.
syz-executor.1  D27344 19947   6935 0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3455 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4180
 schedule+0xd0/0x2a0 kernel/sched/core.c:4255
 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235
 __down_write kernel/locking/rwsem.c:1389 [inline]
 down_write+0x137/0x150 kernel/locking/rwsem.c:1532
 unregister_memcg_shrinker.isra.0+0x26/0x50 mm/vmscan.c:237
 unregister_shrinker+0x230/0x2c0 mm/vmscan.c:403
 deactivate_locked_super+0xe8/0x1f0 fs/super.c:343
 mount_bdev+0x373/0x3b0 fs/super.c:1430
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1558
 do_new_mount fs/namespace.c:2911 [inline]
 do_mount+0x14c5/0x1df0 fs/namespace.c:3237
 __do_sys_mount fs/namespace.c:3447 [inline]
 __se_sys_mount fs/namespace.c:3424 [inline]
 __x64_sys_mount+0x18f/0x230 fs/namespace.c:3424
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45f56a
Code: Bad RIP value.
RSP: 002b:00007f1648df6a68 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 000000000050a400 RCX: 000000000045f56a
RDX: 00007f1648df6ae0 RSI: 00000000200002c0 RDI: 00007f1648df6b00
RBP: 000000000078bf00 R08: 00007f1648df6b40 R09: 00007f1648df6ae0
R10: 0000000000000000 R11: 0000000000000206 R12: 00000000ffffffff
R13: 0000000000000c38 R14: 00000000004ce8ad R15: 00007f1648df76d4
INFO: task syz-executor.1:19947 blocked for more than 149 seconds.
      Not tainted 5.8.0-rc2-next-20200626-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D27344 19947   6935 0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3455 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4180
 schedule+0xd0/0x2a0 kernel/sched/core.c:4255
 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235
 __down_write kernel/locking/rwsem.c:1389 [inline]
 down_write+0x137/0x150 kernel/locking/rwsem.c:1532
 unregister_memcg_shrinker.isra.0+0x26/0x50 mm/vmscan.c:237
 unregister_shrinker+0x230/0x2c0 mm/vmscan.c:403
 deactivate_locked_super+0xe8/0x1f0 fs/super.c:343
 mount_bdev+0x373/0x3b0 fs/super.c:1430
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592