On 10/26/2022 2:32 PM, Alexei Starovoitov wrote:
On Tue, Oct 25, 2022 at 7:42 PM Xu Kuohai <xukuohai@xxxxxxxxxxxxxxx> wrote:From: Xu Kuohai <xukuohai@xxxxxxxxxx> There is a typo in comment for DFS algorithm in bpf/verifier.c. The top element should not be popped until all its neighbors have been checked. Fix it. Fixes: 475fb78fbf48 ("bpf: verifier (add branch/goto checks)") Signed-off-by: Xu Kuohai <xukuohai@xxxxxxxxxx> --- kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b83a8d420520..96ba5ea6d1a6 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10662,7 +10662,7 @@ static int check_return_code(struct bpf_verifier_env *env) * 3 let S be a stack * 4 S.push(v) * 5 while S is not empty - * 6 t <- S.pop() + * 6 t <- S.top()Even with this fix the comment is not quite accurate. I wonder whether we should keep it or delete it completely.
The comment describes the non-recursive DFS algorithm used by the C code. Although it does not describe the full details, it helps us to understand the code, so I think it should be kept.
At least please use 'peek' instead of 'top'.
OK.
