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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
kasprintf.c 
// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/lib/kasprintf.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/stdarg.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/string.h>

/* Simplified asprintf. */
char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
{
	unsigned int first, second;
	char *p;
	va_list aq;

	va_copy(aq, ap);
	first = vsnprintf(NULL, 0, fmt, aq);
	va_end(aq);

	p = kmalloc_track_caller(first+1, gfp);
	if (!p)
		return NULL;

	second = vsnprintf(p, first+1, fmt, ap);
	WARN(first != second, "different return values (%u and %u) from vsnprintf(\"%s\", ...)",
	     first, second, fmt);

	return p;
}
EXPORT_SYMBOL(kvasprintf);

/*
 * If fmt contains no % (or is exactly %s), use kstrdup_const. If fmt
 * (or the sole vararg) points to rodata, we will then save a memory
 * allocation and string copy. In any case, the return value should be
 * freed using kfree_const().
 */
const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list ap)
{
	if (!strchr(fmt, '%'))
		return kstrdup_const(fmt, gfp);
	if (!strcmp(fmt, "%s"))
		return kstrdup_const(va_arg(ap, const char*), gfp);
	return kvasprintf(gfp, fmt, ap);
}
EXPORT_SYMBOL(kvasprintf_const);

char *kasprintf(gfp_t gfp, const char *fmt, ...)
{
	va_list ap;
	char *p;

	va_start(ap, fmt);
	p = kvasprintf(gfp, fmt, ap);
	va_end(ap);

	return p;
}
EXPORT_SYMBOL(kasprintf);
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