bpf: Avoid extra bpf_prog_ksym_find in bpf_stack_walker

Just like previous patch, call bpf_prog_ksym_find once, which lets us
know the prog pointer and as a consequence also test whether we have a
BPF program IP.

Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]>

Author: kkdwivedi

kernel/bpf/helpers.c

@@ -2934,11 +2934,11 @@ static bool bpf_stack_walker(void *cookie, u64 ip, u64 sp, u64 bp)
 	struct bpf_throw_ctx *ctx = cookie;
 	struct bpf_prog *prog;
 
-	if (!is_bpf_text_address(ip))
-		return !ctx->cnt;
 	rcu_read_lock();
 	prog = bpf_prog_ksym_find(ip);
 	rcu_read_unlock();
+	if (!prog)
+		return !ctx->cnt;
 	ctx->cnt++;
 	if (bpf_is_subprog(prog))
 		return true;