Home
last modified time | relevance | path

Searched hist:e6e8df07268c1f75dd9215536e2ce4587b70f977 (Results 1 – 1 of 1) sorted by relevance

/openbmc/linux/drivers/cpufreq/
H A Dcpufreq.cdiff e6e8df07268c1f75dd9215536e2ce4587b70f977 Wed Nov 06 23:08:17 CST 2019 Kai Shen <shenkai8@huawei.com> cpufreq: Add NULL checks to show() and store() methods of cpufreq

Add NULL checks to show() and store() in cpufreq.c to avoid attempts
to invoke a NULL callback.

Though some interfaces of cpufreq are set as read-only, users can
still get write permission using chmod which can lead to a kernel
crash, as follows:

chmod +w /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
echo 1 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

This bug was found in linux 4.19.

Signed-off-by: Kai Shen <shenkai8@huawei.com>
Reported-by: Feilong Lin <linfeilong@huawei.com>
Reviewed-by: Feilong Lin <linfeilong@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>