BUG: memory leak
unreferenced object 0xffff88800d619ba0 (size 16):
  comm "syz-executor.4", pid 4543, jiffies 4294824656 (age 933.681s)
  hex dump (first 16 bytes):
    58 f6 4c 19 80 88 ff ff 00 00 85 09 80 88 ff ff  X.L.............
  backtrace:
    [<00000000b19ab7e7>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000b19ab7e7>] ext4_multi_mount_protect+0x861/0xb20 fs/ext4/mmp.c:367
    [<00000000604e3bc1>] ext4_fill_super+0xa20e/0xcf20 fs/ext4/super.c:4774
    [<000000006cc0c2d2>] mount_bdev+0x331/0x3f0 fs/super.c:1419
    [<00000000f3842938>] legacy_get_tree+0x105/0x220 fs/fs_context.c:592
    [<0000000080e273a9>] vfs_get_tree+0x8e/0x2f0 fs/super.c:1549
    [<00000000e1a7e6ee>] do_new_mount fs/namespace.c:2881 [inline]
    [<00000000e1a7e6ee>] path_mount+0x139a/0x2080 fs/namespace.c:3211
    [<00000000f58a1009>] do_mount fs/namespace.c:3224 [inline]
    [<00000000f58a1009>] __do_sys_mount fs/namespace.c:3432 [inline]
    [<00000000f58a1009>] __se_sys_mount fs/namespace.c:3409 [inline]
    [<00000000f58a1009>] __x64_sys_mount+0x27e/0x300 fs/namespace.c:3409
    [<000000003799aa60>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
    [<000000007d8422c1>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: leak checking failed