From d0b2818efbe27e6c2e0c52621c8db18eb5abb5e1 Mon Sep 17 00:00:00 2001
From: Peter Oskolkov <posk@google.com>
Date: Wed, 16 Jan 2019 10:43:01 -0800
Subject: [PATCH] bpf: fix a (false) compiler warning
An older GCC compiler complains:
kernel/bpf/verifier.c: In function 'bpf_check':
kernel/bpf/verifier.c:4***:13: error: 'prev_offset' may be used uninitialized
in this function [-Werror=maybe-uninitialized]
} else if (krecord[i].insn_offset <= prev_offset) {
^
kernel/bpf/verifier.c:4***:38: note: 'prev_offset' was declared here
u32 i, nfuncs, urec_size, min_size, prev_offset;
Although the compiler is wrong here, the patch makes sure
that prev_offset is always initialized, just to silence the warning.
v2: fix a spelling error in the commit message.
Signed-off-by: Peter Oskolkov <posk@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
kernel/bpf/verifier.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 56674a7c37788..ce87198ecd01e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4997,13 +4997,14 @@ static int check_btf_func(struct bpf_verifier_env *env,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
- u32 i, nfuncs, urec_size, min_size, prev_offset;
+ u32 i, nfuncs, urec_size, min_size;
u32 krec_size = sizeof(struct bpf_func_info);
struct bpf_func_info *krecord;
const struct btf_type *type;
struct bpf_prog *prog;
const struct btf *btf;
void __user *urecord;
+ u32 prev_offset = 0;
int ret = 0;
nfuncs = attr->func_info_cnt;
--
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