cpufreq: dt: fix oops on armada37xx

BugLink: https://bugs.launchpad.net/bugs/1892417
commit 10470dec3decaf5ed3c596f85debd7c42777ae12 upstream.

Commit 0c868627e617e43a295d8 (cpufreq: dt: Allow platform specific
intermediate callbacks) added two function pointers to the
struct cpufreq_dt_platform_data. However, armada37xx_cpufreq_driver_init()
has this struct (pdata) located on the stack and uses only "suspend"
and "resume" fields. So these newly added "get_intermediate" and
"target_intermediate" pointers are uninitialized and contain arbitrary
non-null values, causing all kinds of trouble.

For instance, here is an oops on espressobin after an attempt to change
the cpefreq governor:

[   29.174554] Unable to handle kernel execute from non-executable memory at virtual address ffff00003f87bdc0
...
[   29.269373] pc : 0xffff00003f87bdc0
[   29.272957] lr : __cpufreq_driver_target+0x138/0x580
...

Fixed by zeroing out pdata before use.

Cc: <stable@vger.kernel.org> # v5.7+
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c
index aa0f06dec959cbe0df3c34cc60e337f5142ecdfd..df1c941260d14047e71a3d9d1eaaa633e28ae855 100644 (file)
--- a/drivers/cpufreq/armada-37xx-cpufreq.c
+++ b/drivers/cpufreq/armada-37xx-cpufreq.c
@@ -456,6 +456,7 @@ static int __init armada37xx_cpufreq_driver_init(void)
        /* Now that everything is setup, enable the DVFS at hardware level */
        armada37xx_cpufreq_enable_dvfs(nb_pm_base);
 
+       memset(&pdata, 0, sizeof(pdata));
        pdata.suspend = armada37xx_cpufreq_suspend;
        pdata.resume = armada37xx_cpufreq_resume;