<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Looks good to me! </div></div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">Den mån 16 maj 2022 kl 20:15 skrev Alex Deucher <<a href="mailto:alexdeucher@gmail.com">alexdeucher@gmail.com</a>>: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Mon, May 16, 2022 at 2:10 PM Christian König <<a href="mailto:ckoenig.leichtzumerken@gmail.com" target="_blank">ckoenig.leichtzumerken@gmail.com</a>> wrote: > > Am 16.05.22 um 19:49 schrieb Ernst Sjöstrand: > > Den mån 16 maj 2022 kl 17:13 skrev Alex Deucher <<a href="mailto:alexdeucher@gmail.com" target="_blank">alexdeucher@gmail.com</a>>: >> >> On Sun, May 15, 2022 at 11:46 AM Ernst Sjöstrand <<a href="mailto:ernstp@gmail.com" target="_blank">ernstp@gmail.com</a>> wrote: >> > >> > smatch found this problem on amd-staging-drm-next: >> > >> > drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c:1443 amdgpu_discovery_get_vcn_info() error: buffer overflow 'adev->vcn.vcn_codec_disable_mask' 2 <= 3 >> > >> > This is caused by: >> > #define AMDGPU_MAX_VCN_INSTANCES 2 >> > #define VCN_INFO_TABLE_MAX_NUM_INSTANCES 4 >> > >> > Can we just drop VCN_INFO_TABLE_MAX_NUM_INSTANCES completely and use AMDGPU_MAX_VCN_INSTANCES everywhere instead (and bump it to 4)? >> >> We should be able to bump AMDGPU_MAX_VCN_INSTANCES to 4 (although it >> would waste some memory in the places it is used at this point). >> VCN_INFO_TABLE_MAX_NUM_INSTANCES is part of a firmware structure so we >> can't change that without breaking the firmware structure. >> >> Alex > > > It would be nice to get rid of this pattern and make sure it doesn't happen again when the VCN info table is raised to 5. > It's very similar to the HWIP_MAX_INSTANCE issue. > > > No, as Alex explained that distinction is intentional. > > The firmware definition is 4 for future extensions, that doesn't mean that this is currently used. > > There is currently simply no need to set AMDGPU_MAX_VCN_INSTANCES to more than 2. Right. The attached patch should protect against the scenario you are envisioning. Alex > > Regards, > Christian. > > > //E > > </blockquote></div>