mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 05:04:00 +08:00
bba3d2daa8
In cas of probe failure, devres may free the memory allocated for
rtc->nvram before devm_rtc_release_device() is called. This leads to
rtc_nvram_unregister using it after being freed which may lead to a crash.
This has been shown to happen after commit 461e557b97 ("rtc: nvmem: use
devm_nvmem_register()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
|
|
* RTC subsystem, nvmem interface
|
|
*
|
|
* Copyright (C) 2017 Alexandre Belloni
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/err.h>
|
|
#include <linux/types.h>
|
|
#include <linux/nvmem-consumer.h>
|
|
#include <linux/rtc.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/sysfs.h>
|
|
|
|
/*
|
|
* Deprecated ABI compatibility, this should be removed at some point
|
|
*/
|
|
|
|
static const char nvram_warning[] = "Deprecated ABI, please use nvmem";
|
|
|
|
static ssize_t
|
|
rtc_nvram_read(struct file *filp, struct kobject *kobj,
|
|
struct bin_attribute *attr,
|
|
char *buf, loff_t off, size_t count)
|
|
{
|
|
dev_warn_once(kobj_to_dev(kobj), nvram_warning);
|
|
|
|
return nvmem_device_read(attr->private, off, count, buf);
|
|
}
|
|
|
|
static ssize_t
|
|
rtc_nvram_write(struct file *filp, struct kobject *kobj,
|
|
struct bin_attribute *attr,
|
|
char *buf, loff_t off, size_t count)
|
|
{
|
|
dev_warn_once(kobj_to_dev(kobj), nvram_warning);
|
|
|
|
return nvmem_device_write(attr->private, off, count, buf);
|
|
}
|
|
|
|
static int rtc_nvram_register(struct rtc_device *rtc,
|
|
struct nvmem_device *nvmem, size_t size)
|
|
{
|
|
int err;
|
|
|
|
rtc->nvram = kzalloc(sizeof(struct bin_attribute), GFP_KERNEL);
|
|
if (!rtc->nvram)
|
|
return -ENOMEM;
|
|
|
|
rtc->nvram->attr.name = "nvram";
|
|
rtc->nvram->attr.mode = 0644;
|
|
rtc->nvram->private = nvmem;
|
|
|
|
sysfs_bin_attr_init(rtc->nvram);
|
|
|
|
rtc->nvram->read = rtc_nvram_read;
|
|
rtc->nvram->write = rtc_nvram_write;
|
|
rtc->nvram->size = size;
|
|
|
|
err = sysfs_create_bin_file(&rtc->dev.parent->kobj,
|
|
rtc->nvram);
|
|
if (err) {
|
|
kfree(rtc->nvram);
|
|
rtc->nvram = NULL;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static void rtc_nvram_unregister(struct rtc_device *rtc)
|
|
{
|
|
sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram);
|
|
kfree(rtc->nvram);
|
|
rtc->nvram = NULL;
|
|
}
|
|
|
|
/*
|
|
* New ABI, uses nvmem
|
|
*/
|
|
int rtc_nvmem_register(struct rtc_device *rtc,
|
|
struct nvmem_config *nvmem_config)
|
|
{
|
|
struct nvmem_device *nvmem;
|
|
|
|
if (!nvmem_config)
|
|
return -ENODEV;
|
|
|
|
nvmem_config->dev = rtc->dev.parent;
|
|
nvmem_config->owner = rtc->owner;
|
|
nvmem = devm_nvmem_register(rtc->dev.parent, nvmem_config);
|
|
if (IS_ERR(nvmem))
|
|
return PTR_ERR(nvmem);
|
|
|
|
/* Register the old ABI */
|
|
if (rtc->nvram_old_abi)
|
|
rtc_nvram_register(rtc, nvmem, nvmem_config->size);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_nvmem_register);
|
|
|
|
void rtc_nvmem_unregister(struct rtc_device *rtc)
|
|
{
|
|
/* unregister the old ABI */
|
|
if (rtc->nvram)
|
|
rtc_nvram_unregister(rtc);
|
|
}
|