Commit 4734b0fe authored Apr 04, 2020 by Jeremy Cline Committed by Daniel Borkmann Apr 06, 2020

libbpf: Initialize *nl_pid so gcc 10 is happy

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

parent db5c97f0

tools/lib/bpf/netlink.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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)

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