BUG: memory leak
unreferenced object 0xffff88812471d240 (size 32):
  comm "syz-executor.0", pid 10299, jiffies 4294980227 (age 12.220s)
  hex dump (first 32 bytes):
    30 8c 47 10 81 88 ff ff 00 48 f7 1f 81 88 ff ff  0.G......H......
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000008a1edffa>] kmalloc include/linux/slab.h:552 [inline]
    [<000000008a1edffa>] ext4_multi_mount_protect+0x4a6/0x5d0 fs/ext4/mmp.c:367
    [<00000000a2f9129e>] ext4_fill_super+0x5650/0x5ad0 fs/ext4/super.c:4728
    [<00000000e4598378>] mount_bdev+0x223/0x260 fs/super.c:1366
    [<00000000909cfe44>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:592
    [<00000000d5700d96>] vfs_get_tree+0x28/0x100 fs/super.c:1496
    [<00000000b0b62639>] do_new_mount fs/namespace.c:2878 [inline]
    [<00000000b0b62639>] path_mount+0xc5e/0x1170 fs/namespace.c:3208
    [<00000000873ac359>] do_mount fs/namespace.c:3221 [inline]
    [<00000000873ac359>] __do_sys_mount fs/namespace.c:3429 [inline]
    [<00000000873ac359>] __se_sys_mount fs/namespace.c:3406 [inline]
    [<00000000873ac359>] __x64_sys_mount+0x18e/0x1d0 fs/namespace.c:3406
    [<00000000324bd39b>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<000000005c0369fb>] entry_SYSCALL_64_after_hwframe+0x44/0xa9