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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=nWPYIb/pH6H6oqPWsIPtUjNPbp07s6id5XEc1hMPQDMdeKAuZOc9j8PNXJxfz33n6 G5IxTmlmRhScRf8Rtc8d+7pqOLpyuMN6lUMOhfbf5lTZefaXpD7B6E3/5v9m1xTNDp m+i2jwmBGB+jr7V/SNZYlKjYsTuYkARctVNycKJoDlAUIXVy5KJ41TZo8kC+RuWTco vSV1Z6V0YTo37RIgaBT+JA47S9pvA5P8NoFDBjXkG5xW+1Ddj3Teg0/cbcV7yJ5tKj LOuXPzmtuHuqAqKA4GyOzCA7qcxeXCTdSVdbHMX+vPJboJijElcEOPP7vokRjodtrn NPX5Z2P3YnCig== Date: Thu, 13 Aug 2026 11:51:00 +0300 From: Mike Rapoport To: Nikunj A Dadhania Cc: ljs@kernel.org, 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: <20260813055544.25567-1-nikunj@amd.com> X-Rspamd-Queue-Id: 8801C120007 X-Rspam-User: X-Stat-Signature: iuqsdfhpyf9i5cugxai3iumfn6b7u916 X-Rspamd-Server: rspam06 X-HE-Tag: 1786611075-247358 X-HE-Meta: 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 QhA9Snc6 4CZ3MjZCedWJ9h+eNJALhv1BFVZ2R7c7uv7qdaE9mWM9cyA8HZiZrBWcmKQZgahBQVeNsoPZSsuLLghC8VUIHLiDkODVGePifVoFofWMj4uxcqCTUfACh/YjAcJCO1cVUFcXxWmS9cw0HKABoDyejNRReCxfgazc2Gain6P3/wqFqivZqIgjtbRLw28w4jJascDhXroIhbSxbdRFRb1fge0zA64Pz15nNiddM/dKIVtHqxkCqw58rlB7CsidvBFndXDFFST+o3+3sFgYdPGU+CJv1T0iu9eQylAcDdphbKMVIn2mWb6B0QCtZ+fFrQUXcXrFuuKyswj905WqNxwnx2yf+0yEmuAHjm5CiSRvBpR7CL5bcI1U6WKDEfA== 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 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. > [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.