Commit d0b2818e authored Jan 16, 2019 by Peter Oskolkov Committed by Daniel Borkmann Jan 17, 2019

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>

parent 4edc01b8

kernel/bpf/verifier.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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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