[PATCH AUTOSEL 5.6 01/38] libbpf: Initialize *nl_pid so gcc 10 is happy

Sasha Levin
2020-04-24T12:22:41Z

From: Jeremy Cline <jcline@redhat.com>

[ Upstream commit 4734b0fefbbf98f8c119eb8344efa19dac82cd2c ]

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@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200404051430.698058-1-jcline@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 6d47345a310bd..b294e2aeb3283 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -141,7 +141,7 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
struct ifinfomsg ifinfo;
char attrbuf[64];
} req;
- __u32 nl_pid;
+ __u32 nl_pid = 0;

sock = libbpf_netlink_open(&nl_pid);
if (sock < 0)
@@ -256,7 +256,7 @@ 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)
--
2.20.1