From d2b024d32d6e6f704633a8a474bd883cf9e25254 Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@fb.com>
Date: Tue, 22 Nov 2016 16:52:08 -0800
Subject: [PATCH] samples/bpf: fix sockex2 example
since llvm commit "Do not expand UNDEF SDNode during insn selection lowering"
llvm will generate code that uses uninitialized registers for cases
where C code is actually uses uninitialized data.
So this sockex2 example is technically broken.
Fix it by initializing on the stack variable fully.
Also increase verifier buffer limit, since verifier output
may not fit in 64k for this sockex2 code depending on llvm version.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
samples/bpf/libbpf.h | 2 +-
samples/bpf/sockex2_kern.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h
index ac6edb61b64a2..de96a935068d1 100644
--- a/samples/bpf/libbpf.h
+++ b/samples/bpf/libbpf.h
@@ -18,7 +18,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
int bpf_obj_pin(int fd, const char *pathname);
int bpf_obj_get(const char *pathname);
-#define LOG_BUF_SIZE 65536
+#define LOG_BUF_SIZE (256 * 1024)
extern char bpf_log_buf[LOG_BUF_SIZE];
/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
diff --git a/samples/bpf/sockex2_kern.c b/samples/bpf/sockex2_kern.c
index 44e5846c988f8..f58acfc925561 100644
--- a/samples/bpf/sockex2_kern.c
+++ b/samples/bpf/sockex2_kern.c
@@ -198,7 +198,7 @@ struct bpf_map_def SEC("maps") hash_map = {
SEC("socket2")
int bpf_prog2(struct __sk_buff *skb)
{
- struct bpf_flow_keys flow;
+ struct bpf_flow_keys flow = {};
struct pair *value;
u32 key;
--
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