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Date: Tue, 19 Apr 2022 16:48:29 +0800
From: Zhang Rui <rui.zhang@...el.com>
To: Junwen Wu <wudaemon@....com>, rafael@...nel.org,
daniel.lezcano@...aro.org, amitk@...nel.org
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v1] thermal/core: change mm alloc method to avoid kernel
warning
On Sun, 2022-04-17 at 12:56 +0000, Junwen Wu wrote:
> Very high cooling device max state value makes cooling device stats
> buffer allocation fails,like below.Using kzvalloc instead of kzalloc
> can avoid this issue.
When a cooling device has big max_state, this patch can get ride of the
warning here, but still we end up with the read failure of the
trans_table in sysfs because it is larger than PAGE_SIZE.
$ cat /sys/class/thermal/cooling_device8/stats/trans_table
cat: /sys/class/thermal/cooling_device8/stats/trans_table: File too
large
IMO, unless we can fix both places, I'd suggest we skip allocating and
creating the broken trans_table attr. Like a prototype patch below
thanks,
rui
>From 2a504596d06a91d6f01d25eee71ebcdeff164e59 Mon Sep 17 00:00:00 2001
From: Zhang Rui <rui.zhang@...el.com>
Date: Tue, 19 Apr 2022 16:40:04 +0800
Subject: [PATCH] thermal: thermal_stats: skip broken trans_table
Signed-off-by: Zhang Rui <rui.zhang@...el.com>
---
drivers/thermal/thermal_sysfs.c | 40 ++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 8 deletions(-)
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index f154bada2906..d917489f89bc 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -686,7 +686,8 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
goto unlock;
update_time_in_state(stats);
- stats->trans_table[stats->state * stats->max_states + new_state]++;
+ if (stats->trans_table)
+ stats->trans_table[stats->state * stats->max_states + new_state]++;
stats->state = new_state;
stats->total_trans++;
@@ -741,8 +742,9 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf,
stats->total_trans = 0;
stats->last_time = ktime_get();
- memset(stats->trans_table, 0,
- states * states * sizeof(*stats->trans_table));
+ if (stats->trans_table)
+ memset(stats->trans_table, 0,
+ states * states * sizeof(*stats->trans_table));
for (i = 0; i < stats->max_states; i++)
stats->time_in_state[i] = ktime_set(0, 0);
@@ -805,7 +807,6 @@ static struct attribute *cooling_device_stats_attrs[] = {
&dev_attr_total_trans.attr,
&dev_attr_time_in_state_ms.attr,
&dev_attr_reset.attr,
- &dev_attr_trans_table.attr,
NULL
};
@@ -814,11 +815,25 @@ static const struct attribute_group cooling_device_stats_attr_group = {
.name = "stats"
};
+static struct attribute *cooling_device_stats_ext_attrs[] = {
+ &dev_attr_total_trans.attr,
+ &dev_attr_time_in_state_ms.attr,
+ &dev_attr_reset.attr,
+ &dev_attr_trans_table.attr,
+ NULL
+};
+
+static const struct attribute_group cooling_device_stats_ext_attr_group = {
+ .attrs = cooling_device_stats_ext_attrs,
+ .name = "stats"
+};
+
static void cooling_device_stats_setup(struct thermal_cooling_device *cdev)
{
struct cooling_dev_stats *stats;
unsigned long states;
- int var;
+ int var, size;
+ bool ext = false;
if (cdev->ops->get_max_state(cdev, &states))
return;
@@ -827,14 +842,20 @@ static void cooling_device_stats_setup(struct thermal_cooling_device *cdev)
var = sizeof(*stats);
var += sizeof(*stats->time_in_state) * states;
- var += sizeof(*stats->trans_table) * states * states;
+ size = sizeof(*stats->trans_table) * states * states;
+
+ if (var + size < PAGE_SIZE) {
+ ext = true;
+ var += size;
+ }
stats = kzalloc(var, GFP_KERNEL);
if (!stats)
return;
stats->time_in_state = (ktime_t *)(stats + 1);
- stats->trans_table = (unsigned int *)(stats->time_in_state + states);
+ if (ext)
+ stats->trans_table = (unsigned int *)(stats->time_in_state + states);
cdev->stats = stats;
stats->last_time = ktime_get();
stats->max_states = states;
@@ -843,7 +864,10 @@ static void cooling_device_stats_setup(struct thermal_cooling_device *cdev)
/* Fill the empty slot left in cooling_device_attr_groups */
var = ARRAY_SIZE(cooling_device_attr_groups) - 2;
- cooling_device_attr_groups[var] = &cooling_device_stats_attr_group;
+ if (ext)
+ cooling_device_attr_groups[var] = &cooling_device_stats_ext_attr_group;
+ else
+ cooling_device_attr_groups[var] = &cooling_device_stats_attr_group;
}
static void cooling_device_stats_destroy(struct thermal_cooling_device *cdev)
--
2.17.1
>
> [ 7.392644]WARNING: CPU: 7 PID: 1747 at mm/page_alloc.c:5090
> __alloc_pages_nodemask+0x1c0/0x3dc
> [ 7.392989]Call trace:
> [ 7.392992]__alloc_pages_nodemask+0x1c0/0x3dc
> [ 7.392995]kmalloc_order+0x54/0x358
> [ 7.392997]kmalloc_order_trace+0x34/0x1bc
> [ 7.393001]__kmalloc+0x5cc/0x9c8
> [ 7.393005]thermal_cooling_device_setup_sysfs+0x90/0x218
> [ 7.393008]__thermal_cooling_device_register+0x160/0x7a4
> [ 7.393012]thermal_of_cooling_device_register+0x14/0x24
> [ 7.393140]backlight_cdev_register+0x88/0x100 [msm_drm]
>
>
> Signed-off-by: Junwen Wu <wudaemon@....com>
> ---
> drivers/thermal/thermal_sysfs.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/thermal_sysfs.c
> b/drivers/thermal/thermal_sysfs.c
> index f154bada2906..361e0d0c241b 100644
> --- a/drivers/thermal/thermal_sysfs.c
> +++ b/drivers/thermal/thermal_sysfs.c
> @@ -829,7 +829,7 @@ static void cooling_device_stats_setup(struct
> thermal_cooling_device *cdev)
> var += sizeof(*stats->time_in_state) * states;
> var += sizeof(*stats->trans_table) * states * states;
>
> - stats = kzalloc(var, GFP_KERNEL);
> + stats = kvzalloc(var, GFP_KERNEL);
> if (!stats)
> return;
>
> @@ -848,7 +848,7 @@ static void cooling_device_stats_setup(struct
> thermal_cooling_device *cdev)
>
> static void cooling_device_stats_destroy(struct
> thermal_cooling_device *cdev)
> {
> - kfree(cdev->stats);
> + kvfree(cdev->stats);
> cdev->stats = NULL;
> }
>
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