BUG: memory leak
unreferenced object 0xffff888008d4f980 (size 16):
  comm "syz-executor.7", pid 5760, jiffies 4295091719 (age 24.036s)
  hex dump (first 16 bytes):
    d0 91 52 4a 80 88 ff ff 00 e0 a1 44 80 88 ff ff  ..RJ.......D....
  backtrace:
    [<0000000053a0330b>] kmalloc include/linux/slab.h:552 [inline]
    [<0000000053a0330b>] ext4_multi_mount_protect+0x861/0xb20 fs/ext4/mmp.c:367
    [<000000007756119a>] ext4_fill_super+0xa20e/0xcf20 fs/ext4/super.c:4774
    [<000000000f174c66>] mount_bdev+0x331/0x3f0 fs/super.c:1419
    [<0000000086b006b3>] legacy_get_tree+0x105/0x220 fs/fs_context.c:592
    [<000000005c37c985>] vfs_get_tree+0x8e/0x2f0 fs/super.c:1549
    [<00000000a5e5424a>] do_new_mount fs/namespace.c:2881 [inline]
    [<00000000a5e5424a>] path_mount+0x139a/0x2080 fs/namespace.c:3211
    [<000000000fee832d>] do_mount fs/namespace.c:3224 [inline]
    [<000000000fee832d>] __do_sys_mount fs/namespace.c:3432 [inline]
    [<000000000fee832d>] __se_sys_mount fs/namespace.c:3409 [inline]
    [<000000000fee832d>] __x64_sys_mount+0x27e/0x300 fs/namespace.c:3409
    [<00000000e0b9c95a>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
    [<000000006b026c19>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: leak checking failed