BUG: memory leak
unreferenced object 0xffff888123ddecc0 (size 32):
  comm "syz-executor.2", pid 10535, jiffies 4294981276 (age 16.610s)
  hex dump (first 32 bytes):
    40 63 11 10 81 88 ff ff 00 90 c8 1f 81 88 ff ff  @c..............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000d6e36932>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000d6e36932>] ext4_multi_mount_protect+0x4a6/0x5d0 fs/ext4/mmp.c:367
    [<00000000d1b15051>] ext4_fill_super+0x5650/0x5ad0 fs/ext4/super.c:4768
    [<00000000a91d6c8b>] mount_bdev+0x223/0x260 fs/super.c:1366
    [<0000000064c0ad83>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:592
    [<000000001df0c459>] vfs_get_tree+0x28/0x100 fs/super.c:1496
    [<000000003cf11bc6>] do_new_mount fs/namespace.c:2881 [inline]
    [<000000003cf11bc6>] path_mount+0xc5e/0x1170 fs/namespace.c:3211
    [<00000000c93c2a93>] do_mount fs/namespace.c:3224 [inline]
    [<00000000c93c2a93>] __do_sys_mount fs/namespace.c:3432 [inline]
    [<00000000c93c2a93>] __se_sys_mount fs/namespace.c:3409 [inline]
    [<00000000c93c2a93>] __x64_sys_mount+0x18e/0x1d0 fs/namespace.c:3409
    [<00000000badabef9>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<000000003a1a4d6b>] entry_SYSCALL_64_after_hwframe+0x44/0xa9