BUG: memory leak
unreferenced object 0xffff888123ae3b00 (size 32):
  comm "syz-executor.4", pid 18200, jiffies 4295072693 (age 9.190s)
  hex dump (first 32 bytes):
    f8 ba 85 16 81 88 ff ff 00 20 4a 23 81 88 ff ff  ......... J#....
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8175fb76>] kmalloc include/linux/slab.h:556 [inline]
    [<ffffffff8175fb76>] ext4_multi_mount_protect+0x4a6/0x5d0 fs/ext4/mmp.c:367
    [<ffffffff8179e104>] ext4_fill_super+0x5864/0x5b30 fs/ext4/super.c:4786
    [<ffffffff81560733>] mount_bdev+0x223/0x260 fs/super.c:1368
    [<ffffffff815c113b>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:592
    [<ffffffff8155e328>] vfs_get_tree+0x28/0x100 fs/super.c:1498
    [<ffffffff8159ea9e>] do_new_mount fs/namespace.c:2905 [inline]
    [<ffffffff8159ea9e>] path_mount+0xc3e/0x1110 fs/namespace.c:3235
    [<ffffffff8159f6be>] do_mount fs/namespace.c:3248 [inline]
    [<ffffffff8159f6be>] __do_sys_mount fs/namespace.c:3456 [inline]
    [<ffffffff8159f6be>] __se_sys_mount fs/namespace.c:3433 [inline]
    [<ffffffff8159f6be>] __x64_sys_mount+0x18e/0x1d0 fs/namespace.c:3433
    [<ffffffff8435405a>] do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
    [<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae