CVE-2026-43244 kcm: fix zero-frag skb in frag_list on partial sendmsg error

In the Linux kernel, the following vulnerability has been resolved: kcm: fix zero-frag skb in fraglist on partial sendmsg error Syzkaller reported a warning in kcmwritemsgs when processing a message with a zero-fragment skb in the fraglist. When kcmsendmsg fills MAXSKBFRAGS fragments in the curre...