ext4: fix buffer_head leak in ext4_init_orphan_info

In the Linux kernel, the following vulnerability has been resolved: ext4: fix buffer_head leak in ext4_init_orphan_info ext4_init_orphan_info() reads orphan file blocks with ext4_bread() and stores the returned buffer_head in oi->of_binfo[i].ob_bh. If ext4_bread() succeeds but the orphan block magic or checksum validation fails, the function jumps to out_free. However, the old out_free loop starts releasing buffers from i - 1, so the current buffer_head at index i is skipped. This leaks the buffer_head reference obtained by ext4_bread() on the bad magic and bad checksum error paths. Fix this by tracking the number of successfully read buffer_heads and releasing exactly those buffer_heads on the error path.

Where it's fixed