BUG: memory leak
unreferenced object 0xffff88804193a920 (size 16):
  comm "syz-executor.2", pid 15850, jiffies 4295722550 (age 14.387s)
  hex dump (first 16 bytes):
    f8 e9 4b 42 80 88 ff ff 00 20 70 3f 80 88 ff ff  ..KB..... p?....
  backtrace:
    [<0000000021091fc0>] kmalloc include/linux/slab.h:552 [inline]
    [<0000000021091fc0>] ext4_multi_mount_protect+0x861/0xb20 fs/ext4/mmp.c:367
    [<000000006395e6a9>] ext4_fill_super+0xa20e/0xcf20 fs/ext4/super.c:4774
    [<00000000985f80f0>] mount_bdev+0x331/0x3f0 fs/super.c:1419
    [<000000002083f52b>] legacy_get_tree+0x105/0x220 fs/fs_context.c:592
    [<00000000714f23fa>] vfs_get_tree+0x8e/0x2f0 fs/super.c:1549
    [<000000002f9d4e60>] do_new_mount fs/namespace.c:2881 [inline]
    [<000000002f9d4e60>] path_mount+0x139a/0x2080 fs/namespace.c:3211
    [<00000000ed2798c5>] do_mount fs/namespace.c:3224 [inline]
    [<00000000ed2798c5>] __do_sys_mount fs/namespace.c:3432 [inline]
    [<00000000ed2798c5>] __se_sys_mount fs/namespace.c:3409 [inline]
    [<00000000ed2798c5>] __x64_sys_mount+0x27e/0x300 fs/namespace.c:3409
    [<00000000d67aa8da>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
    [<000000001698d08f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: leak checking failed