On Fri, Apr 3, 2020 at 10:15 PM Jeremy Cline <jcline@xxxxxxxxxx> wrote: > > Builds of Fedora's kernel-tools package started to fail with "may be > used uninitialized" warnings for nl_pid in bpf_set_link_xdp_fd() and > bpf_get_link_xdp_info() on the s390 architecture. > > Although libbpf_netlink_open() always returns a negative number when it > does not set *nl_pid, the compiler does not determine this and thus > believes the variable might be used uninitialized. Assuage gcc's fears > by explicitly initializing nl_pid. > > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1807781 > Signed-off-by: Jeremy Cline <jcline@xxxxxxxxxx> > --- Yep, unfortunately compiler is not that smart. Acked-by: Andrii Nakryiko <andriin@xxxxxx> > tools/lib/bpf/netlink.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c > index 18b5319025e19..9a14694176de0 100644 > --- a/tools/lib/bpf/netlink.c > +++ b/tools/lib/bpf/netlink.c > @@ -142,7 +142,7 @@ static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, > struct ifinfomsg ifinfo; > char attrbuf[64]; > } req; > - __u32 nl_pid; > + __u32 nl_pid = 0; > > sock = libbpf_netlink_open(&nl_pid); > if (sock < 0) > @@ -288,7 +288,7 @@ int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info, > { > struct xdp_id_md xdp_id = {}; > int sock, ret; > - __u32 nl_pid; > + __u32 nl_pid = 0; > __u32 mask; > > if (flags & ~XDP_FLAGS_MASK || !info_size) > -- > 2.26.0 >
