BUG: memory leak
unreferenced object 0xffff88800c664500 (size 16):
  comm "syz-executor.0", pid 15517, jiffies 4296609499 (age 18.277s)
  hex dump (first 16 bytes):
    d0 21 82 20 80 88 ff ff 00 20 b6 18 80 88 ff ff  .!. ..... ......
  backtrace:
    [<00000000d4b3f543>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000d4b3f543>] ext4_multi_mount_protect+0x861/0xb20 fs/ext4/mmp.c:367
    [<000000006a40479a>] ext4_fill_super+0xa20e/0xcf20 fs/ext4/super.c:4774
    [<000000002066b85d>] mount_bdev+0x331/0x3f0 fs/super.c:1419
    [<000000005ab55d11>] legacy_get_tree+0x105/0x220 fs/fs_context.c:592
    [<000000002257a97c>] vfs_get_tree+0x8e/0x2f0 fs/super.c:1549
    [<000000007c4756de>] do_new_mount fs/namespace.c:2881 [inline]
    [<000000007c4756de>] path_mount+0x139a/0x2080 fs/namespace.c:3211
    [<00000000af68a48c>] do_mount fs/namespace.c:3224 [inline]
    [<00000000af68a48c>] __do_sys_mount fs/namespace.c:3432 [inline]
    [<00000000af68a48c>] __se_sys_mount fs/namespace.c:3409 [inline]
    [<00000000af68a48c>] __x64_sys_mount+0x27e/0x300 fs/namespace.c:3409
    [<00000000c47efb07>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
    [<000000006637c8db>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: leak checking failed