Re: [PATCH v3 2/2] x86 mce: use new printk recursion disablinginterface

From: Yanmin Zhang
Date: Mon Jun 04 2012 - 20:31:31 EST


On Mon, 2012-06-04 at 19:12 +0200, Borislav Petkov wrote:
> On Mon, May 28, 2012 at 10:56:04AM +0800, ShuoX Liu wrote:
> > From: ShuoX Liu <shuox.liu@xxxxxxxxx>
> >
> > Disable printk recursion to make sure MCE logs printed out.
> >
> > Signed-off-by: Yanmin Zhang <yanmin_zhang@xxxxxxxxxxxxxxx>
> > Signed-off-by: ShuoX Liu <shuox.liu@xxxxxxxxx>
> > ---
> > arch/x86/kernel/cpu/mcheck/mce.c | 2 ++
> > 1 files changed, 2 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> > index 2afcbd2..365c35d 100644
> > --- a/arch/x86/kernel/cpu/mcheck/mce.c
> > +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> > @@ -1015,6 +1015,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
> > DECLARE_BITMAP(toclear, MAX_NR_BANKS);
> > char *msg = "Unknown";
> >
> > + printk_recursion_check_disable();
> > atomic_inc(&mce_entry);
> >
> > this_cpu_inc(mce_exception_count);
> > @@ -1144,6 +1145,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
> > mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
> > out:
> > atomic_dec(&mce_entry);
> > + printk_recursion_check_enable();
> > sync_core();
>
> This is still adding the recursion check things in do_machine_check
> instead of in print_mce.
Boris,

You are seeing an old patch. The new patches V4 are:
https://lkml.org/lkml/2012/6/3/176
https://lkml.org/lkml/2012/6/3/177


The new patches change mce_panic instead of do_machine_check.

>
> Also, this commit message above needs more explanation why we want to
> disable the recursion check on an MCE, maybe an example...
V4 doesn't have the comment. We would add it in V5.

Thanks.


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