Re: [PATCH] objtool: Fix stack overflow in validate_branch()

[David Laight]

On Tue, 2 Dec 2025 15:01:17 -0800
Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:

...
> +	while (fgets(line, sizeof(line), fp)) {
> +		if (strstr(line, "[stack]")) {
> +			if (sscanf(line, "%lx-%lx", &stack_start, &stack_end) != 2) {
> +				ERROR_GLIBC("sscanf");
> +				ret = -1;
> +				goto done;
> +			}
> +			stack_limit = stack_end - rlim.rlim_cur;
> +			goto done;

That assumes 'stack grows down'.
Someone will copy the code onto a 'backwards stack' system one day.
(I can't remember which ones they are.)

	David