Re: [PATCH][RT] x86: Fix an RT MCE crash

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 6 Jul 2016 15:43:51 +0200
Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> On 07/06/2016 03:32 PM, Steven Rostedt wrote:
> > On Wed, 6 Jul 2016 07:03:43 -0500
> > Corey Minyard <cminyard@mvista.com> wrote:
> >   
> >>> ---
> >>> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> >>> index aaf4b9b94f38..cc70d98a30f6 100644
> >>> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> >>> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> >>> @@ -1391,7 +1391,8 @@ static int mce_notify_work_init(void)
> >>>   
> >>>   static void mce_notify_work(void)
> >>>   {
> >>> -	wake_up_process(mce_notify_helper);
> >>> +	if (mce_notify_helper)
> >>> +		wake_up_process(mce_notify_helper);
> >>>   }  
> > 
> > Actually, this appears to be the fix in 4.6-rt.  
> 
> This is in there since it was switched to swork instead of using its
> own thread and is also in v4.1:
> 
> https://git.kernel.org/cgit/linux/kernel/git/rt/linux-rt-devel.git/tree/arch/x86/kernel/cpu/mcheck/mce.c?h=linux-4.1.y-rt#n1387
> 
> as part of x86-mce-use-swait-queue-for-mce-wakeups.patch. And this
> patch was first part of v3.18.9-rt4 as a new patch dropping x86-mce-
> Defer-mce-wakeups-to-threads-for-PREEMPT_RT.patch.
> 

I'm doing backports now. I'm currently on 4.1, but trying to move
quickly.

Corey, what commits did you backport (plus the one Boris showed)? And
does that fix your issue?

-- Steve