+ Tony.
On Thu, Jun 30, 2016 at 11:51:01AM -0400, Steven Rostedt 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
Do you have any logs which hint at when exactly the MCE gets raised?
> > >> 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)
Hmm, what is mce_notify_work_init() ?
This must be some RT-homegrown thing.
What it is supposed to do? Upstream is much different from 3.10 or
whatever that kernel version is.
> > >> if (!mce_notify_helper)
> > >> return -ENOMEM;
> > >>
> > >> + notify_work_ready = true;
> > >> return 0;
> > >> }
> > >>
> > >> static void mce_notify_work(void)
That is gone upstream too AFAICT.
> > >> {
> > >> - wake_up_process(mce_notify_helper);
> > >> + if (notify_work_ready)
> > >> + wake_up_process(mce_notify_helper);
> > >> }
> > >> #else
> > >> static void mce_notify_work(void)
Color me puzzled.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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