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. [0] Specifically, the following (ranges of) commits: 9ffbe8ac05dbb4ab4a4836a55a47fc6be945a38f (-> lockdep_assert_held_write) e1bfa87399e372446454ecbaeba2800f0a385733..5da04cc86d1215fd9fe0e5c88ead6e8428a75e56 fec88ab0af9706b2201e5daf377c5031c62d11f7^..fec88ab0af9706b2201e5daf377c5031c62d11f7 -- Earthling Michel Dänzer | https://www.amd.com Libre software enthusiast | Mesa and X developer
