From d0b2818efbe27e6c2e0c52621c8db18eb5abb5e1 Mon Sep 17 00:00:00 2001 From: Peter Oskolkov 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 Acked-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann --- 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 56674a7c3778..ce87198ecd01 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; -- 2.30.2