On 2019-07-16 6:35 p.m., Jason Gunthorpe wrote: > On Tue, Jul 16, 2019 at 06:31:09PM +0200, Michel Dänzer wrote: >> On 2019-07-15 7:25 p.m., Jason Gunthorpe wrote: >>> On Mon, Jul 15, 2019 at 06:51:06PM +0200, Michel Dänzer wrote: >>>> >>>> With a KASAN enabled kernel built from amd-staging-drm-next, the >>>> attached use-after-free is pretty reliably detected during a piglit gpu run. >>> >>> Does this branch you are testing have the hmm.git merged? I think from >>> the name it does not? >> >> Indeed, no. >> >> >>> Use after free's of this nature were something that was fixed in >>> hmm.git.. >>> >>> I don't see an obvious way you can hit something like this with the >>> new code arrangement.. >> >> I tried merging the hmm-devmem-cleanup.4 changes[0] into my 5.2.y + >> drm-next for 5.3 kernel. While the result didn't hit the problem, all >> GL_AMD_pinned_memory piglit tests failed, so I suspect the problem was >> simply avoided by not actually hitting the HMM related functionality. >> >> It's possible that I made a mistake in merging the changes, or that I >> missed some other required changes. But it's also possible that the HMM >> changes broke the corresponding user-pointer functionality in amdgpu. > > Not sure, this was all Tested by the AMD team so it should work, I > hope. It can't, due to the issue pointed out by Linus in the "drm pull for 5.3-rc1" thread: DRM_AMDGPU_USERPTR still depends on ARCH_HAS_HMM, which no longer exists, so it can't be enabled. Fixing that up manually, it successfully finished a piglit run with that functionality enabled as well. -- Earthling Michel Dänzer | https://www.amd.com Libre software enthusiast | Mesa and X developer
