CVE-2024-36903: Use of Uninitialized Resource

In the Linux kernel, the following vulnerability has been resolved:

ipv6: Fix potential uninit-value access in __ip6_make_skb()

As it was done in commit fc1092f51567 ("ipv4: Fix uninit-value access in __ip_make_skb()") for IPv4, check FLOWI_FLAG_KNOWN_NH on fl6->flowi6_flags instead of testing HDRINCL on the socket to avoid a race condition which causes uninit-value access.