Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 20 Mar 2024 16:32:53 +0100 | From | Michal Hocko <> | Subject | Re: CVE-2024-26628: drm/amdkfd: Fix lock dependency warning |
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On Thu 14-03-24 11:09:38, Lee Jones wrote: > On Fri, 08 Mar 2024, Michal Hocko wrote: > > > On Wed 06-03-24 06:46:11, Greg KH wrote: > > [...] > > > Possible unsafe locking scenario: > > > > > > CPU0 CPU1 > > > ---- ---- > > > lock(&svms->lock); > > > lock(&mm->mmap_lock); > > > lock(&svms->lock); > > > lock((work_completion)(&svm_bo->eviction_work)); > > > > > > I believe this cannot really lead to a deadlock in practice, because > > > svm_range_evict_svm_bo_worker only takes the mmap_read_lock if the BO > > > refcount is non-0. That means it's impossible that svm_range_bo_release > > > is running concurrently. However, there is no good way to annotate this. > > > > OK, so is this even a bug (not to mention a security/weakness)? > > Looks like the patch fixes a warning which can crash some kernels. So > the CVE appears to be fixing that, rather than the impossible deadlock.
Are you talking about lockdep warning or anything else? -- Michal Hocko SUSE Labs
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