CVE-2025-39847 ppp: fix memory leak in pad_compress_skb

In the Linux kernel, the following vulnerability has been resolved: ppp: fix memory leak in padcompressskb If allocskb fails in padcompressskb, it returns NULL without releasing the old skb. The caller does: skb = padcompressskbppp, skb; if !skb goto drop; drop: kfreeskbskb; When padcompressskb...