edk2-stable202111 Re: [edk2-devel] [PATCH] MdeModulePkg AtaAtapiPassThru: Skip the potential NULL pointer access

["Leif Lindholm" <leif@nuviainc.com>]

Since BZ3732 has been triggered by a standard build of a platform in
edk2-platforms, I would request that this fix is brought into the
upcoming stable tag.

SbsaQemu isn't a "real" platform, so I don't consider that in itself
sufficient reason, but I feel the risk of it affecting other
(including out-of-tree) platforms justifies it.

Best Regards,

Leif

On Tue, Nov 23, 2021 at 06:10:14 -0700, Rebecca Cran wrote:
> Acked-by: Rebecca Cran <rebecca@nuviainc.com>
> 
> 
> I've confirmed that this patch fixes the exception I was seeing when running
> the DEBUG build of SbsaQemu.
> 
> 
> -- 
> 
> Rebecca Cran
> 
> 
> On 11/15/21 7:53 PM, gaoliming wrote:
> > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3732
> > Recent change c974257821208fc6191779d1ddea918499f165b8 exposes this potential issue.
> > 
> > Signed-off-by: Liming Gao <gaoliming@byosoft.com.cn>
> > Cc: Hao A Wu <hao.a.wu@intel.com>
> > Cc: Ray Ni <ray.ni@intel.com>
> > ---
> >   MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c | 7 +++++++
> >   1 file changed, 7 insertions(+)
> > 
> > diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c
> > index 7626bac38d..bda900a161 100644
> > --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c
> > +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c
> > @@ -885,6 +885,13 @@ AhciPrintStatusBlock (
> >     IN UINT32                DebugLevel
> >     )
> >   {
> > +  //
> > +  // Skip NULL pointer
> > +  //
> > +  if (AtaStatusBlock == NULL) {
> > +    return;
> > +  }
> > +
> >     //
> >     // Only print status and error since we have all of the rest printed as
> >     // a part of command block print.