Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 31 May 2023 10:03:36 -0700 | From | Ricardo Neri <> | Subject | Re: [PATCH v4 1/3] cacheinfo: Add arch specific early level initializer |
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On Wed, May 31, 2023 at 01:22:01PM +0100, Sudeep Holla wrote: > On Thu, May 18, 2023 at 10:34:14AM +0100, Sudeep Holla wrote: > > On Wed, May 17, 2023 at 06:27:03PM -0700, Ricardo Neri wrote: > > > On Mon, May 15, 2023 at 10:36:08AM +0100, Sudeep Holla wrote: > > > > On Wed, May 10, 2023 at 12:12:07PM -0700, Ricardo Neri wrote: > > > > > Hi, > > > > > > > > > > I had posted a patchset[1] for x86 that initializes > > > > > ci_cacheinfo(cpu)->num_leaves during SMP boot. > > > > > > > > > > > > > It is entirely clear to me if this is just a clean up or a fix to some > > > > issue you faced ? Just wanted to let you know Prateek from AMD has couple > > > > of fixes [2] > > > > > > My first patch is a bug fix. The second patch is clean up that results > > > from fixing the bug in patch 1. > > > > > > > > > > > > This means that early_leaves and a late cache_leaves() are equal but > > > > > per_cpu_cacheinfo(cpu) is never allocated. Currently, x86 does not use > > > > > fetch_cache_info(). > > > > > > > > > > I think that we should check here that per_cpu_cacheinfo() has been allocated to > > > > > take care of the case in which early and late cache leaves remain the same: > > > > > > > > > > - if (cache_leaves(cpu) <= early_leaves) > > > > > + if (cache_leaves(cpu) <= early_leaves && per_cpu_cacheinfo(cpu)) > > > > > > > > > > Otherwise, in v6.4-rc1 + [1] I observe a NULL pointer dereference from > > > > > last_level_cache_is_valid(). > > > > > > > > > > > > > I think this is different issue as Prateek was just observing wrong info > > > > after cpuhotplug operations. But the patches manage the cpumap_populated > > > > state better with the patches. Can you please look at that as weel ? > > > > > > I verified that the patches from Prateek fix a different issue. I was able > > > to reproduce his issue. His patches fixes it. > > > > > > I still see my issue after applying Prateek's patches. > > > > Thanks, I thought it is different issue and good that you were able to test > > them as well. Please post a proper patch for the NULL ptr dereference you > > are hitting on x86. > > Gentle ping! Are you still observing NULL ptr dereference with v6.4-rcx ?
Yes, I still observe it on v6.4-rc4.
> If so, can you please post the fix as a proper patch ? Some of the patches > in v6.4-rc1 are being backported, so I prefer to have all the known issues > fixed before that happens. Sorry for the nag, but backport is the reason > I am pushing for this.
Sure. Sorry for the delay. I have the patch ready and post this week. I will post it as part my previous patches in [1].
Thanks and BR, Ricardo
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