BUG: memory leak
unreferenced object 0xffff888125139400 (size 32):
  comm "syz-executor.4", pid 12292, jiffies 4294991199 (age 9.060s)
  hex dump (first 32 bytes):
    60 fb 24 0f 81 88 ff ff 00 f8 fc 23 81 88 ff ff  `.$........#....
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000006c47d360>] kmalloc include/linux/slab.h:552 [inline]
    [<000000006c47d360>] ext4_multi_mount_protect+0x4a6/0x5d0 fs/ext4/mmp.c:367
    [<000000007ccb1e73>] ext4_fill_super+0x5650/0x5ad0 fs/ext4/super.c:4768
    [<000000005fecab53>] mount_bdev+0x223/0x260 fs/super.c:1366
    [<000000006faf1ead>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:592
    [<00000000b0e5967f>] vfs_get_tree+0x28/0x100 fs/super.c:1496
    [<00000000bf406c89>] do_new_mount fs/namespace.c:2878 [inline]
    [<00000000bf406c89>] path_mount+0xc5e/0x1170 fs/namespace.c:3208
    [<00000000a798a5e1>] do_mount fs/namespace.c:3221 [inline]
    [<00000000a798a5e1>] __do_sys_mount fs/namespace.c:3429 [inline]
    [<00000000a798a5e1>] __se_sys_mount fs/namespace.c:3406 [inline]
    [<00000000a798a5e1>] __x64_sys_mount+0x18e/0x1d0 fs/namespace.c:3406
    [<00000000b8454cb2>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<0000000048cc1162>] entry_SYSCALL_64_after_hwframe+0x44/0xa9