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b=omdXoTrcdHsNFbdpmr+nH8KapdBZLg20P32XW68CN35Qw/yi47HqzWe7UnaEo09F7 DjBX+0/SEXz8rEJiffc/BKCLjU+IK6cMW+8SN8F+ApLdfhGShIciGVTJ2RMzbj0oeQ /yZuCV2V4cJVCNOJeunr8tweiTSIDm3lQfwUOCV6pCMTXXlkLAESrBVeKM4iHUeBwa t2lQwQcO/fDNi4wiUIYYb+nIqZV9QSZjdtNGWwHzLkx6tRZwp6b1DerpmcwK2D+UtF 6zAfWcF4HAj+WKRIcF76jj00LjO2mDgOiWVNxqJHpiLW5CZc4f+LHcgFy7KGh2T/am HrLl8ZAGFcBDQ== Date: Thu, 13 Aug 2026 10:23:56 +0100 From: "Lorenzo Stoakes (ARM)" To: Mike Rapoport Cc: Nikunj A Dadhania , akpm@linux-foundation.org, baolu.lu@linux.intel.com, bp@alien8.de, dave.hansen@linux.intel.com, david@kernel.org, den@openvz.org, devnexen@gmail.com, hpa@zytor.com, iommu@lists.linux.dev, jgg@ziepe.ca, jgross@suse.com, jirislaby@kernel.org, kas@kernel.org, kevin.tian@intel.com, liam@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lists@steffen.cc, luto@kernel.org, mingo@redhat.com, peterz@infradead.org, pfalcato@suse.de, shakeel.butt@linux.dev, stable@vger.kernel.org, surenb@google.com, syzbot@syzkaller.appspotmail.com, tglx@kernel.org, toshi.kani@hpe.com, vbabka@kernel.org, vishal.moola@gmail.com, will@kernel.org, x86@kernel.org, bharata@amd.com, Ananth.Narayan@amd.com Subject: Re: [PATCH 0/5] x86/mm/pat: CPA fixes Message-ID: References: <20260813055544.25567-1-nikunj@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: B7C3740004 X-Stat-Signature: z86zrqrhi8mu85hc4cqd1j5dqxcrh555 X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1786613062-132329 X-HE-Meta: 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 2tFosJff BGn13m54WfC3yB/S0egeLW7d/9f18M9BZhbcdS8oxVx7qt0m8mx7OhmfCfUcNkDHOdRYClvGB/JLUEP7whG9bg3ND2nm3Ov5e4nxFzK/g8QXDzt9EqZucjHlYt/9mxQItNhXVDDXEpndOgFCTPc05edsQWrWaHB6gtH7U8JeUrNg2gZJDmT4ehEn+E567f29+wMsuvVASqUFTfxqrkNA8sc+/h0IZq5tX+dGrQIdntepzUgKRkAuscXKUynQcS/I26D73oK+D5SScDUkVBzDjnf7P4tV3fWvdW5nJYO1B7Ql1gc3BHNhBkkhAvicTyc4UagSEAUWx5vYjpEm89HA6ymaD16RykdSkvbE+uA5fGtWSh8n+6Wa/p81FiA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 13, 2026 at 11:51:00AM +0300, Mike Rapoport wrote: > On Thu, Aug 13, 2026 at 05:55:44AM +0000, Nikunj A Dadhania wrote: > > On Fri, Aug 07, 2026 at 04:36:08PM +0100, Lorenzo Stoakes (ARM) wrote: > > > +static void poke_vmalloc_pages_safe(struct page **pages, void *addr, > > > + bool cross_page_boundary) > > > +{ > > > + guard(mmap_read_lock)(&init_mm); > > > + poke_vmalloc_pages(pages, addr, cross_page_boundary); > > > +} > > > > Tested just the proposed patch from this email (without the rest of the > > CPA fixes series) on the 512-guest concurrent boot harness (details in > > For this fix to actually fix anything, the patches that add locking of > mmap_lock to CPA are needed still. And just in time the fully respun series (based on tip tree x86/mm) is in: https://lore.kernel.org/all/20260813-cpa-fixes-v2-0-39b4ff90f91d@kernel.org/ Please do try with the full series applied. > > > [1]) and still see the memcmp BUG, I havent hit the first BUG though: > > > > kernel BUG at arch/x86/kernel/alternative.c:2727! > > Oops: invalid opcode: 0000 [#1] SMP NOPTI > > CPU: 1 UID: 0 PID: 485 Comm: (udev-worker) Not tainted 7.2.0-rc5-pokesafe+ #42 PREEMPT(full) > > RIP: 0010:__text_poke.cold+0xdb/0x2af > > > > The instrumentation captured the following before the memcmp BUG: > > > > SMP alternatives: __text_poke: memcmp failed at addr=ffffffffc06ce1bb len=4 > > SMP alternatives: __text_poke: expected (src): 2e 2e 31 c0 > > SMP alternatives: __text_poke: found (dst): f9 b8 9b d3 > > SMP alternatives: __text_poke: pfn at poke time (vmalloc_to_page): 8ece > > SMP alternatives: __text_poke: pfn at readback time (vmalloc_to_page): c6ce > > SMP alternatives: __text_poke: page table dump for addr: > > PGD 2f042067 P4D 2f043067 PUD 2f045067 PMD c6001a1 > > > > pfn acquired at the start of __text_poke() (0x8ece) differs from pfn > > at readback time (0xc6ce) in the instrumentaion. > > > > [1] https://lore.kernel.org/all/20260812063316.21371-1-nikunj@amd.com/ > > > > Regards, > > Nikunj > > -- > Sincerely yours, > Mike. -- Cheers, Lorenzo