Re: [PATCH V2] acpi: apei: clear error status before acknowledging the error

[Baicar, Tyler]

On 8/24/2017 2:14 AM, Borislav Petkov wrote:
> On Thu, Aug 03, 2017 at 04:12:31PM -0600, Tyler Baicar wrote:
> > Currently we acknowledge errors before clearing the error status.
> > This could cause a new error to be populated by firmware in-between
> > the error acknowledgment and the error status clearing which would
> > cause the second error's status to be cleared without being handled.
> > So, clear the error status before acknowledging the errors.
> >
> > Also, make sure to acknowledge the error if the error status read
> > fails.
> >
> > V2: Only send error ack if there was an error populated
> >      Remove curly braces that are no longer needed
> >
> > Signed-off-by: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx>
> > ---
> >   drivers/acpi/apei/ghes.c | 9 +++------
> >   1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> > index d661d45..cda4a4f 100644
> > --- a/drivers/acpi/apei/ghes.c
> > +++ b/drivers/acpi/apei/ghes.c
> > @@ -743,17 +743,14 @@ static int ghes_proc(struct ghes *ghes)
> >   	}
> >   	ghes_do_proc(ghes, ghes->estatus);
> >   
> > +out:
> > +	ghes_clear_estatus(ghes);
> >   	/*
> >   	 * GHESv2 type HEST entries introduce support for error acknowledgment,
> >   	 * so only acknowledge the error if this support is present.
> >   	 */
> > -	if (is_hest_type_generic_v2(ghes)) {
> > +	if (is_hest_type_generic_v2(ghes) && rc != -ENOENT)
> I think you should do something like this:
>
> out:
>          ghes_clear_estatus(ghes);
>
> 	if (rc == -ENOENT)
>                  return rc;
>
> 	/*
>           * GHESv2 type HEST entries introduce support for error acknowledgment,
>           * so only acknowledge the error if this support is present.
>           */
>          if (is_hest_type_generic_v2(ghes))
>                  return ghes_ack_error(ghes->generic_v2);
>
>          return rc;
>
>
> First check the -ENOENT because if there's no entry, you don't need to
> ACK anything anyway.
>
> And then only if it is an entry present and it is v2, you can ACK it.
>
> Hmmm?
Looks good to me, I'll send a v3 with this change.

Thanks,
Tyler

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