CVE-2026-43099 ipv4: icmp: fix null-ptr-deref in icmp_build_probe()

In the Linux kernel, the following vulnerability has been resolved: ipv4: icmp: fix null-ptr-deref in icmpbuildprobe ipv6stub-ipv6devfind may return ERRPTR-EAFNOSUPPORT when the IPv6 stack is not active CONFIGIPV6=m and not loaded, and passing this error pointer to devhold will cause a kernel cra...