On Thu, 30 Jun 2016 09:49:19 -0500
Corey Minyard <minyard@xxxxxxx> wrote:
> On 06/30/2016 08:43 AM, Steven Rostedt wrote:
> > On Thu, 30 Jun 2016 08:24:49 -0500
> > minyard@xxxxxxx wrote:
> >
> >> From: Corey Minyard <cminyard@xxxxxxxxxx>
> >>
> >> On some x86 systems an MCE interrupt would come in before the kernel
> >> was ready for it. Looking at the latest RT code, it has similar
> >> (but not quite the same) code, except it adds a bool that tells if
> >> MCE handling is initialized. Add the same bool for older versions.
> >>
> >> Signed-off-by: Corey Minyard <cminyard@xxxxxxxxxx>
> >> ---
> >> arch/x86/kernel/cpu/mcheck/mce.c | 5 ++++-
> >> 1 file changed, 4 insertions(+), 1 deletion(-)
> >>
> >> We noticed this issue on a new Broadwell system when we booted RT
> >> on it. This patch is for 3.10, I'm not sure if it applies to
> >> other kernel versions.
> > Do you mean other 'older' versions? and that this works with the
> > versions after 3.10 without this patch?
>
> I haven't look at supported kernel versions besides 3.10 and 4.4.
> The fix was from the 4.4 version of this code. This patch fixes
> v3.10-rt; I can look at finding which other versions need this. I
> was planning to do this, but I wanted to get the patch out for
> comments first.
I'm not an MCE expert (I just Cc'd one though ;-)
OK, so you are saying that the fix was from 4.4-rt? I can go and look
for it, and if so, I can add it to the "backport" patches I need to do.
Which I need to go and do that soon (backport patches from previous
versions). It may already be in that list.
-- Steve
>
> -corey
>
> > -- Steve
> >
> >> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> >> index aaf4b9b..7125584 100644
> >> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> >> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> >> @@ -1365,6 +1365,7 @@ static void __mce_notify_work(void)
> >> }
> >>
> >> #ifdef CONFIG_PREEMPT_RT_FULL
> >> +static bool notify_work_ready __read_mostly;
> >> struct task_struct *mce_notify_helper;
> >>
> >> static int mce_notify_helper_thread(void *unused)
> >> @@ -1386,12 +1387,14 @@ static int mce_notify_work_init(void)
> >> if (!mce_notify_helper)
> >> return -ENOMEM;
> >>
> >> + notify_work_ready = true;
> >> return 0;
> >> }
> >>
> >> static void mce_notify_work(void)
> >> {
> >> - wake_up_process(mce_notify_helper);
> >> + if (notify_work_ready)
> >> + wake_up_process(mce_notify_helper);
> >> }
> >> #else
> >> static void mce_notify_work(void)
--
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