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drivers: soc: qcom: rpm_stats: Add mutex lock for shared data 

The buffer allocated in rpmstats_show need to be protected
as there can be a possiblity of use-after-free scenario.
Process A              B
        |              |
      open             |
        |              |
      read started     |
        |             close

Add mutex lock to protect the buffer to avoid this.

Also allow reading RPM stats information using sysfs nodes.

The stats are available at
	/sys/power/system_sleep/stats

Change-Id: I28ab98e264fc4e425f23c71ddc6dcc8f275d8f6b
Signed-off-by: Naresh Malladi <namall@codeaurora.org>
This commit is contained in:
Naresh Malladi 2017-07-04 15:57:12 +05:30 committed by Gerrit - the friendly Code Review server
parent fa173fa679
commit a9dcbcf326
1 changed files with 16 additions and 13 deletions
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29
drivers/soc/qcom/rpm_stats.c
View File

@ -389,22 +389,26 @@ static ssize_t rpmstats_show(struct kobject *kobj,
{
struct msm_rpmstats_private_data *prvdata = NULL;
struct msm_rpmstats_platform_data *pdata = NULL;
ssize_t ret;
mutex_lock(&rpm_stats_mutex);
pdata = GET_PDATA_OF_ATTR(attr);
prvdata =
kmalloc(sizeof(*prvdata), GFP_KERNEL);
if (!prvdata)
return -ENOMEM;
if (!prvdata) {
ret = -ENOMEM;
goto kmalloc_fail;
}
prvdata->reg_base = ioremap_nocache(pdata->phys_addr_base,
pdata->phys_size);
if (!prvdata->reg_base) {
kfree(prvdata);
pr_err("%s: ERROR could not ioremap start=%pa, len=%u\n",
__func__, &pdata->phys_addr_base,
pdata->phys_size);
return -EBUSY;
ret = -EBUSY;
goto ioremap_fail;
}
prvdata->read_idx = prvdata->num_records = prvdata->len = 0;
@ -426,23 +430,22 @@ static ssize_t rpmstats_show(struct kobject *kobj,
prvdata);
}
return snprintf(buf, prvdata->len, prvdata->buf);
ret = snprintf(buf, prvdata->len, prvdata->buf);
iounmap(prvdata->reg_base);
ioremap_fail:
kfree(prvdata);
kmalloc_fail:
mutex_unlock(&rpm_stats_mutex);
return ret;
}
static int msm_rpmstats_create_sysfs(struct msm_rpmstats_platform_data *pd)
{
struct kobject *module_kobj = NULL;
struct kobject *rpmstats_kobj = NULL;
struct msm_rpmstats_kobj_attr *rpms_ka = NULL;
int ret = 0;
module_kobj = kset_find_obj(module_kset, KBUILD_MODNAME);
if (!module_kobj) {
pr_err("%s: Cannot find module_kset\n", __func__);
return -ENODEV;
}
rpmstats_kobj = kobject_create_and_add("rpmstats", module_kobj);
rpmstats_kobj = kobject_create_and_add("system_sleep", power_kobj);
if (!rpmstats_kobj) {
pr_err("%s: Cannot create rpmstats kobject\n", __func__);
ret = -ENOMEM;