From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CCCF3A640C; Thu, 13 Aug 2026 09:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786613063; cv=none; b=FGypTYSYxJqdnhEvSo5n3f2uK/Ue/d7+eUaLH4XGn121EdeHljfJdd8RBFIqS401oQIwjzPPd0W8OTlZn5gUgjRyAZizYS91F5FWpphK4seEPc2zjnCrF3OqjuAmXNDZQraxroiqj6b/Y+fLJus3XrY+fhrRZ08s2c2c+AXnU88= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786613063; c=relaxed/simple; bh=QXI5fJmyAVrjjh6pg49MWzlN+T8dCb5xmjxbtmshjVc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YlUmuGiSSl5q0kKthI7Srx1RHFSHEojc/tG4Ff2m48D4L+LcYAMpK5+rXYI1QdVop4zKY96WPuH52JKXisRp/RE5Q+7yzI5MeTIKRA5K2bFBNLsWHaHwV08QJCYx+aDkwkSdkBdSnNym01Gd1aNtp7Kps6ltBRbabWTjEp3otuY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=omdXoTrc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="omdXoTrc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D4211F000E9; Thu, 13 Aug 2026 09:24:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786613062; bh=M9U0BwCwOlA2q71JSGR94TVR71so4Y5WWmqxkhrxnts=; h=Date:From:To:Cc:Subject:References:In-Reply-To; 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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