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[84.3.50.134]) by smtp.gmail.com with ESMTPSA id ah1sm4955923ejc.43.2020.08.13.12.30.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Aug 2020 12:30:10 -0700 (PDT) Date: Thu, 13 Aug 2020 21:30:08 +0200 From: Ingo Molnar To: Joerg Roedel Cc: Linus Torvalds , "Jason A. Donenfeld" , Linux Kernel Mailing List , Thomas Gleixner , Borislav Petkov , Peter Zijlstra , Andrew Morton Subject: Re: [GIT PULL] x86/mm changes for v5.9 Message-ID: <20200813193008.GB2338781@gmail.com> References: <20200803190354.GA1293087@gmail.com> <20200805110348.GA108872@zx2c4.com> <20200806131034.GA2067370@gmail.com> <20200806185723.GA24304@suse.de> <20200806212019.GA2149204@gmail.com> <20200807084728.GA29510@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200807084728.GA29510@suse.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Joerg Roedel wrote: > On Thu, Aug 06, 2020 at 11:20:19PM +0200, Ingo Molnar wrote: > > I've reverted it in x86/urgent as well earlier today, can send you > > that tree right now if you prefer that route. > > I sent a fix for preallocate_vmalloc_pages() to correctly pre-allocate > the vmalloc PGD entries. I verified that it works and that > swapper_pg_dir contains the correct entries now. This should also fix > the issue Jason is seeing. Thanks! There's one thing left to do. Linus has reverted the patch which exposed this bug: 7b4ea9456dd3: ("Revert "x86/mm/64: Do not sync vmalloc/ioremap mappings"") and has applied your fix: 995909a4e22b: ("x86/mm/64: Do not dereference non-present PGD entries") I think now we can re-apply the original commit: 8bb9bf242d1f: ("x86/mm/64: Do not sync vmalloc/ioremap mappings") Mind re-sending it, with an updated changelog that explains why it's now truly safe? Would be tentatively scheduled for v5.10 though, we've had enough excitement in this area for v5.9 I think. :-/ > Sorry for screwing this up :-( No problem, and it was my fault too: I sent 8bb9bf242d1f to Linus too quickly, just 7 days after applying it - x86/mm patches usually need a few weeks of testing. Thanks, Ingo