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
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
test_free_pages.c
// SPDX-License-Identifier: GPL-2.0+
/*
* test_free_pages.c: Check that free_pages() doesn't leak memory
* Copyright (c) 2020 Oracle
* Author: Matthew Wilcox <willy@infradead.org>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/module.h>
static void test_free_pages(gfp_t gfp)
{
unsigned int i;
for (i = 0; i < 1000 * 1000; i++) {
unsigned long addr = __get_free_pages(gfp, 3);
struct page *page = virt_to_page(addr);
/* Simulate page cache getting a speculative reference */
get_page(page);
free_pages(addr, 3);
put_page(page);
}
}
static int m_in(void)
{
pr_info("Testing with GFP_KERNEL\n");
test_free_pages(GFP_KERNEL);
pr_info("Testing with GFP_KERNEL | __GFP_COMP\n");
test_free_pages(GFP_KERNEL | __GFP_COMP);
pr_info("Test completed\n");
return 0;
}
static void m_ex(void)
{
}
module_init(m_in);
module_exit(m_ex);
MODULE_AUTHOR("Matthew Wilcox <willy@infradead.org>");
MODULE_LICENSE("GPL");
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