Re: [edk2-devel] [PATCH 2/2] MdeModulePkg/Bus/Ata/AtaAtapiPassThru: Fix UNUSED_VALUE Coverity issue

["Ard Biesheuvel" <ardb@kernel.org>]

On Mon, 5 Jun 2023 at 10:10, Ranbir Singh <rsingh@ventanamicro.com> wrote:
>
> I counted myself as not the right person to decide what all to do if Status is not successful. Adding the DEBUG statement from the Coverity aspect doesn't count as a fix as RELEASE mode behavior remains the same.
>
> In the comments / description, I already mentioned - Assuming, this non-usage is deliberate, so as such I did not intend to hide anything - and left it in the status quo.
>
> The patch proposed may not be appropriate, but should now give a thinking point to active module developers / owners / maintainers if they indeed feel that there is a bug here and it needs to be fixed.
>

Thanks - I agree that it is a good thing that people are aware of this now.

> On Mon, Jun 5, 2023 at 4:33 AM Ard Biesheuvel <ardb@kernel.org> wrote:
>>
>> On Sat, 3 Jun 2023 at 18:04, Pedro Falcato <pedro.falcato@gmail.com> wrote:
>> >
>> > On Fri, Jun 2, 2023 at 8:42 PM Ranbir Singh <rsingh@ventanamicro.com> wrote:
>> > >
>> > > From: Ranbir Singh <Ranbir.Singh3@Dell.com>
>> > >
>> > > The return value stored in Status after call to SetDriveParameters
>> > > is not made of any use thereafter and hence it remains as UNUSED.
>> > > Assuming, this non-usage is deliberate, the storage in Status can be
>> > > done away with.
>> > >
>> > > Cc: Hao A Wu <hao.a.wu@intel.com>
>> > > Cc: Ray Ni <ray.ni@intel.com>
>> > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4204
>> > > Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
>> > > ---
>> > >  MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c | 2 +-
>> > >  1 file changed, 1 insertion(+), 1 deletion(-)
>> > >
>> > > diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
>> > > index 75403886e44a..c6d637afa989 100644
>> > > --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
>> > > +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
>> > > @@ -2555,7 +2555,7 @@ DetectAndConfigIdeDevice (
>> > >        DriveParameters.Heads          = (UINT8)(((ATA5_IDENTIFY_DATA *)(&Buffer.AtaData))->heads - 1);
>> > >        DriveParameters.MultipleSector = (UINT8)((ATA5_IDENTIFY_DATA *)(&Buffer.AtaData))->multi_sector_cmd_max_sct_cnt;
>> > >
>> > > -      Status = SetDriveParameters (Instance, IdeChannel, IdeDevice, &DriveParameters, NULL);
>> > > +      SetDriveParameters (Instance, IdeChannel, IdeDevice, &DriveParameters, NULL);
>> >
>> > I'm /fairly/ sure this is wrong and that you need to use Status.
>> >
>>
>> Yeah, removing the assignment fixes the coverity warning, but now you
>> are hiding a bug instead of fixing it.
>>
>> SetDriveParameters () can apparently fail, and this is being ignored.
>> At the very least, we should emit a diagnostic here in DEBUG mode to
>> log this. E.g.,
>>
>> DEBUG ((DEBUG_WARN, "%a: SetDriveParameters () failed - %r\n",
>> __func__, Status));