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Revision b5d281f6c16dd432b618bdfd36ddba1a58d5b603 authored by Christian Marangi on 19 June 2022, 22:03:51 UTC, committed by Chanwoo Choi on 29 June 2022, 20:11:17 UTC 
PM / devfreq: Rework freq_table to be local to devfreq struct
 
On a devfreq PROBE_DEFER, the freq_table in the driver profile struct,
is never reset and may be leaved in an undefined state.

This comes from the fact that we store the freq_table in the driver
profile struct that is commonly defined as static and not reset on
PROBE_DEFER.
We currently skip the reinit of the freq_table if we found
it's already defined since a driver may declare his own freq_table.

This logic is flawed in the case devfreq core generate a freq_table, set
it in the profile struct and then PROBE_DEFER, freeing the freq_table.
In this case devfreq will found a NOT NULL freq_table that has been
freed, skip the freq_table generation and probe the driver based on the
wrong table.

To fix this and correctly handle PROBE_DEFER, use a local freq_table and
max_state in the devfreq struct and never modify the freq_table present
in the profile struct if it does provide it.

Fixes: 0ec09ac2cebe ("PM / devfreq: Set the freq_table of devfreq device")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
1 parent f44b799
Raw File
test_sort.c 
// SPDX-License-Identifier: GPL-2.0-only

#include <kunit/test.h>

#include <linux/sort.h>
#include <linux/slab.h>
#include <linux/module.h>

/* a simple boot-time regression test */

#define TEST_LEN 1000

static int cmpint(const void *a, const void *b)
{
	return *(int *)a - *(int *)b;
}

static void test_sort(struct kunit *test)
{
	int *a, i, r = 1;

	a = kunit_kmalloc_array(test, TEST_LEN, sizeof(*a), GFP_KERNEL);
	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, a);

	for (i = 0; i < TEST_LEN; i++) {
		r = (r * 725861) % 6599;
		a[i] = r;
	}

	sort(a, TEST_LEN, sizeof(*a), cmpint, NULL);

	for (i = 0; i < TEST_LEN-1; i++)
		KUNIT_ASSERT_LE(test, a[i], a[i + 1]);
}

static struct kunit_case sort_test_cases[] = {
	KUNIT_CASE(test_sort),
	{}
};

static struct kunit_suite sort_test_suite = {
	.name = "lib_sort",
	.test_cases = sort_test_cases,
};

kunit_test_suites(&sort_test_suite);

MODULE_LICENSE("GPL");
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