Re: [tip:smp/hotplug] cpufreq: Fix up conversion to hotplug state machine

2016-09-20 Thread Borislav Petkov 
On Tue, Sep 20, 2016 at 08:07:08AM -0700, tip-bot for Sebastian Andrzej Siewior 
wrote:
> Commit-ID:  5372e054a1928fe704cf0a5e2e139645a777b50a
> Gitweb: http://git.kernel.org/tip/5372e054a1928fe704cf0a5e2e139645a777b50a
> Author: Sebastian Andrzej Siewior 
> AuthorDate: Tue, 20 Sep 2016 16:56:28 +0200
> Committer:  Thomas Gleixner 
> CommitDate: Tue, 20 Sep 2016 16:59:21 +0200
> 
> cpufreq: Fix up conversion to hotplug state machine
> 
> The function cpufreq_register_driver() returns zero on success and since
> commit 27622b061eb4 ("cpufreq: Convert to hotplug state machine")
> erroneously a positive number. Due to the "if (x) assume_error" construct
> all callers assumed an error and as a consequence the cpu freq kworker
> crashes with a NULL pointer dereference.
> 
> Reset the return value back to zero in the success case.
> 
> Fixes: 27622b061eb4 ("cpufreq: Convert to hotplug state machine")
> Reported-by: Borislav Petkov 

-and-tested-by: me.

Thanks!

-- 
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.

[tip:smp/hotplug] cpufreq: Fix up conversion to hotplug state machine

2016-09-20 Thread tip-bot for Sebastian Andrzej Siewior 
Commit-ID:  5372e054a1928fe704cf0a5e2e139645a777b50a
Gitweb: http://git.kernel.org/tip/5372e054a1928fe704cf0a5e2e139645a777b50a
Author: Sebastian Andrzej Siewior 
AuthorDate: Tue, 20 Sep 2016 16:56:28 +0200
Committer:  Thomas Gleixner 
CommitDate: Tue, 20 Sep 2016 16:59:21 +0200

cpufreq: Fix up conversion to hotplug state machine

The function cpufreq_register_driver() returns zero on success and since
commit 27622b061eb4 ("cpufreq: Convert to hotplug state machine")
erroneously a positive number. Due to the "if (x) assume_error" construct
all callers assumed an error and as a consequence the cpu freq kworker
crashes with a NULL pointer dereference.

Reset the return value back to zero in the success case.

Fixes: 27622b061eb4 ("cpufreq: Convert to hotplug state machine")
Reported-by: Borislav Petkov 
Reported-and-tested-by: Ingo Molnar 
Signed-off-by: Sebastian Andrzej Siewior 
Cc: pet...@infradead.org
Cc: r...@rjwysocki.net
Link: http://lkml.kernel.org/r/20160920145628.lp2bmq72ip3oi...@linutronix.de
Signed-off-by: Thomas Gleixner 

---
 drivers/cpufreq/cpufreq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e0bc632..8b44de4 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2503,6 +2503,7 @@ int cpufreq_register_driver(struct cpufreq_driver 
*driver_data)
if (ret < 0)
goto err_if_unreg;
hp_online = ret;
+   ret = 0;
 
pr_debug("driver %s up and running\n", driver_data->name);
goto out;