Re: [PATCH] x86/mce: Need to let kill_proc() send signal to doomed process

[Borislav Petkov <bp@amd64.org>]

On Mon, Jul 09, 2012 at 01:34:36PM -0700, Tony Luck wrote:
> In commit dad1743e5993f19b3d7e7bd0fb35dc45b5326626
>   x86/mce: Only restart instruction after machine check recovery if it is safe
> 
> we fixed mce_notify_process() to force a signal to the current process
> if it was not restartable (RIPV bit not set in MCG_STATUS). But doing
> it here means that the process doesn't get told the virtual address of
> the fault via siginfo_t->si_addr. This would prevent application level
> recovery from the fault.
> 
> Make a new MF_MUST_KILL flag bit for memory_failure() et. al. to use
> so that we will provide the right information with the signal.
> 
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
> 
> v2: Fix brainfart where I forgot to check mi->restartable to decide whether
>     to pass in the new MF_MUST_KILL bit [Thanks Boris for spotting this!]
>     Use same style syntax !!(flags & MF_MUST_KILL) [Also from Boris]
>     Faked tests with RIPV set and not set ... and found that we need one
>     more check on MF_MUST_KILL earlier in hwpoison_user_mappings() to
>     make sure it doesn't think the clean page case is recoverable.

Ok, now it makes pretty good sense.

Acked-by: Borislav Petkov <borislav.petkov@amd.com>

Thanks.

-- 
Regards/Gruss,
Boris.

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