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Update devfreq next for v6.8

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Detailed description for this pull request:
 1. Fix buffer overflow of trans_stat_show sysfs node on devfreq core
 - Fix buffer overflow of trans_stat_show sysfs node to replace
   sprintf with scnprintf and then replace it with sysfs_emit
   according to the syfs guide.
 
 2. Fix the timer list corruption when frequent switching of governor
 by synchronizing the devfreq_moniotr_start and _stop function.
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Merge tag 'devfreq-next-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux into pm-devfreq

Merge devfreq updates for v6.8 from Chanwoo Choi:

"1. Fix buffer overflow of trans_stat_show sysfs node on devfreq core

    - Fix buffer overflow of trans_stat_show sysfs node to replace
      sprintf with scnprintf and then replace it with sysfs_emit
      according to the syfs guide.

 2. Fix the timer list corruption when frequent switching of governor
    by synchronizing the devfreq_moniotr_start and _stop function."

* tag 'devfreq-next-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux:
  PM / devfreq: Synchronize devfreq_monitor_[start/stop]
  PM / devfreq: Convert to use sysfs_emit_at() API
  PM / devfreq: Fix buffer overflow in trans_stat_show
This commit is contained in:
Rafael J. Wysocki 2023-12-21 14:43:46 +01:00
commit bfd7b2d95e
2 changed files with 67 additions and 26 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
Documentation/ABI/testing/sysfs-class-devfreq
View file

@ -52,6 +52,9 @@ Description:
echo 0 > /sys/class/devfreq/.../trans_stat
If the transition table is bigger than PAGE_SIZE, reading
this will return an -EFBIG error.
What: /sys/class/devfreq/.../available_frequencies
Date: October 2012
Contact: Nishanth Menon <nm@ti.com>

90
drivers/devfreq/devfreq.c
View file

@ -461,10 +461,14 @@ static void devfreq_monitor(struct work_struct *work)
if (err)
dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
if (devfreq->stop_polling)
goto out;
queue_delayed_work(devfreq_wq, &devfreq->work,
msecs_to_jiffies(devfreq->profile->polling_ms));
mutex_unlock(&devfreq->lock);
out:
mutex_unlock(&devfreq->lock);
trace_devfreq_monitor(devfreq);
}
@ -483,6 +487,10 @@ void devfreq_monitor_start(struct devfreq *devfreq)
if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
return;
mutex_lock(&devfreq->lock);
if (delayed_work_pending(&devfreq->work))
goto out;
switch (devfreq->profile->timer) {
case DEVFREQ_TIMER_DEFERRABLE:
INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
@ -491,12 +499,16 @@ void devfreq_monitor_start(struct devfreq *devfreq)
INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
break;
default:
return;
goto out;
}
if (devfreq->profile->polling_ms)
queue_delayed_work(devfreq_wq, &devfreq->work,
msecs_to_jiffies(devfreq->profile->polling_ms));
out:
devfreq->stop_polling = false;
mutex_unlock(&devfreq->lock);
}
EXPORT_SYMBOL(devfreq_monitor_start);
@ -513,6 +525,14 @@ void devfreq_monitor_stop(struct devfreq *devfreq)
if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
return;
mutex_lock(&devfreq->lock);
if (devfreq->stop_polling) {
mutex_unlock(&devfreq->lock);
return;
}
devfreq->stop_polling = true;
mutex_unlock(&devfreq->lock);
cancel_delayed_work_sync(&devfreq->work);
}
EXPORT_SYMBOL(devfreq_monitor_stop);
@ -1688,7 +1708,7 @@ static ssize_t trans_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct devfreq *df = to_devfreq(dev);
ssize_t len;
ssize_t len = 0;
int i, j;
unsigned int max_state;
@ -1697,7 +1717,7 @@ static ssize_t trans_stat_show(struct device *dev,
max_state = df->max_state;
if (max_state == 0)
return sprintf(buf, "Not Supported.\n");
return sysfs_emit(buf, "Not Supported.\n");
mutex_lock(&df->lock);
if (!df->stop_polling &&
@ -1707,31 +1727,49 @@ static ssize_t trans_stat_show(struct device *dev,
}
mutex_unlock(&df->lock);
len = sprintf(buf, " From : To\n");
len += sprintf(buf + len, " :");
for (i = 0; i < max_state; i++)
len += sprintf(buf + len, "%10lu",
df->freq_table[i]);
len += sprintf(buf + len, " time(ms)\n");
len += sysfs_emit_at(buf, len, " From : To\n");
len += sysfs_emit_at(buf, len, " :");
for (i = 0; i < max_state; i++) {
if (df->freq_table[i] == df->previous_freq)
len += sprintf(buf + len, "*");
else
len += sprintf(buf + len, " ");
len += sprintf(buf + len, "%10lu:", df->freq_table[i]);
for (j = 0; j < max_state; j++)
len += sprintf(buf + len, "%10u",
df->stats.trans_table[(i * max_state) + j]);
len += sprintf(buf + len, "%10llu\n", (u64)
jiffies64_to_msecs(df->stats.time_in_state[i]));
if (len >= PAGE_SIZE - 1)
break;
len += sysfs_emit_at(buf, len, "%10lu",
df->freq_table[i]);
}
if (len >= PAGE_SIZE - 1)
return PAGE_SIZE - 1;
len += sysfs_emit_at(buf, len, " time(ms)\n");
for (i = 0; i < max_state; i++) {
if (len >= PAGE_SIZE - 1)
break;
if (df->freq_table[2] == df->previous_freq)
len += sysfs_emit_at(buf, len, "*");
else
len += sysfs_emit_at(buf, len, " ");
if (len >= PAGE_SIZE - 1)
break;
len += sysfs_emit_at(buf, len, "%10lu:", df->freq_table[i]);
for (j = 0; j < max_state; j++) {
if (len >= PAGE_SIZE - 1)
break;
len += sysfs_emit_at(buf, len, "%10u",
df->stats.trans_table[(i * max_state) + j]);
}
if (len >= PAGE_SIZE - 1)
break;
len += sysfs_emit_at(buf, len, "%10llu\n", (u64)
jiffies64_to_msecs(df->stats.time_in_state[i]));
}
if (len < PAGE_SIZE - 1)
len += sysfs_emit_at(buf, len, "Total transition : %u\n",
df->stats.total_trans);
if (len >= PAGE_SIZE - 1) {
pr_warn_once("devfreq transition table exceeds PAGE_SIZE. Disabling\n");
return -EFBIG;
}
len += sprintf(buf + len, "Total transition : %u\n",
df->stats.total_trans);
return len;
}