Thanks a lot Vlastimil, and Peter for the pointers! Many thanks Will for actually fixing it (v5.12)! Thanks, Mohamed On Mon, Nov 30, 2020 at 1:50 PM Will Deacon <will@xxxxxxxxxx> wrote: > > On Mon, Nov 30, 2020 at 01:02:41PM +0100, Peter Zijlstra wrote: > > On Mon, Nov 30, 2020 at 12:51:59PM +0100, Vlastimil Babka wrote: > > > On 11/30/20 11:37 AM, Mohamed Alzayat wrote: > > > > > > Thanks for confirming, Vlastimil! > > > > > > > > The first bad commit is: 0758cd8304942292e95a0f750c374533db378b32 > > > > asm-generic/tlb: avoid potential double flush > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0758cd8304942292e95a0f750c374533db378b32 > > > > > > > > Reverting this commit solves the problem, but this might not be the > > > > right way of fixing it. > > > > > > Thanks for bisecting! Let's CC people involved in that commit. All important > > > should be in the quoted conversation above. > > > > There's a thread about it here: > > > > https://lkml.kernel.org/r/20201120143557.6715-1-will@xxxxxxxxxx > > > > That softdirty code really shouldn't be using mmu_gather imo, but I'm > > still not clear on what exactly is broken why there. > > I'll spin a v2 of that series soon, so I'll add folks here to cc. The > fact that a test noticed the missing invalidation is a pretty good reason > for us to add it back! Thanks, everyone! I appreciate your helpful comments and pointers, looking forward to the v2 of that series. Until then, reverting to double TLB flush works fine on recent kernels (tested on v5.10-rc5). Thanks, Mohamed > > Will >
