Re: [bug report] net: ipa: reduce arguments to ipa_table_init_add()

[Dan Carpenter <error27@gmail.com>]

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On Tue, Nov 15, 2022 at 11:00:49AM -0600, Alex Elder wrote:
> > drivers/net/ipa/ipa_table.c
> >     413			count = mem->size / sizeof(__le64);
> >     414			hash_count = hash_mem && hash_mem->size / sizeof(__le64);
> 
> Line 414 is wrong.  It should be:
>     hash_count = hash_mem ? hash_mem->size / sizeof(__le64) : 0;
> 

Heh.  It really feels like this line should have generated a checker
warning as well.  I've created two versions.  The first complains when
ever there is a divide used as a condition:

	if (a / b) {

The other complains when it's part of a logical && or ||.

	if (a && a / b) {

drivers/net/ipa/ipa_table.c:414 ipa_table_init_add() warn: divide condition: 'hash_mem->size / 8'
drivers/net/ipa/ipa_table.c:414 ipa_table_init_add() warn: divide condition (logical): 'hash_mem->size / 8'

I'll test them out tonight and see if either gives useful results.

regards,
dan carpenter


[-- Attachment #2: check_divide_condition.c --]
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/*
 * Copyright (C) 2022 Dan Carpenter.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
 */

#include "smatch.h"
#include "smatch_extra.h"

static int my_id;

static void match_condition1(struct expression *expr)
{
	char *name;

	if (expr->type != EXPR_BINOP || expr->op != '/')
		return;

	name = expr_to_str(expr);
	sm_warning("divide condition: '%s'", name);
	free_string(name);
}

static void match_condition2(struct expression *expr)
{
	struct expression *parent;
	char *name;

	if (expr->type != EXPR_BINOP || expr->op != '/')
		return;

	parent = expr_get_parent_expr(expr);
	while (parent && parent->type == EXPR_PREOP && parent->op == '(')
		parent = expr_get_parent_expr(parent);

	if (!parent || parent->type != EXPR_LOGICAL)
		return;

	name = expr_to_str(expr);
	sm_warning("divide condition (logical): '%s'", name);
	free_string(name);
}

void check_divide_condition(int id)
{
	my_id = id;

	add_hook(&match_condition1, CONDITION_HOOK);
	add_hook(&match_condition2, CONDITION_HOOK);

}