backports: genetlink: avoid NULL dereference

If we fail to allocate extack, we fall back to the code path
that tries to send an error *with* extack, but that will
access our extack pointer. It also doesn't make sense, so just
return an error back to netlink immediately and let it handle
sending the error message to userspace.

Signed-off-by: Johannes Berg <>
Signed-off-by: Luca Coelho <>
1 file changed