From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4E9421F92D for ; Thu, 11 May 2023 13:14:14 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4F832113E; Thu, 11 May 2023 06:14:58 -0700 (PDT) Received: from [10.1.34.59] (C02Z41KALVDN.cambridge.arm.com [10.1.34.59]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D65933F5A1; Thu, 11 May 2023 06:14:12 -0700 (PDT) Message-ID: Date: Thu, 11 May 2023 14:14:11 +0100 Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [PATCH v1 1/5] mm: vmalloc must set pte via arch code To: Andrew Morton , "Matthew Wilcox (Oracle)" , "Kirill A. Shutemov" , SeongJae Park Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, damon@lists.linux.dev References: <20230511125848.78621-1-ryan.roberts@arm.com> <20230511125848.78621-2-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: <20230511125848.78621-2-ryan.roberts@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit My appologies for the noise: A blank line between Cc and Subject has broken the subject and grouping in lore. Please Ignore this, I will resend. On 11/05/2023 13:58, Ryan Roberts wrote: > It is bad practice to directly set pte entries within a pte table. > Instead all modifications must go through arch-provided helpers such as > set_pte_at() to give the arch code visibility and allow it to validate > (and potentially modify) the operation. > > Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function") > Signed-off-by: Ryan Roberts > --- > mm/vmalloc.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 9683573f1225..d8d2fe797c55 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2899,10 +2899,13 @@ struct vmap_pfn_data { > static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private) > { > struct vmap_pfn_data *data = private; > + pte_t ptent; > > if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx]))) > return -EINVAL; > - *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot)); > + > + ptent = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot)); > + set_pte_at(&init_mm, addr, pte, ptent); > return 0; > } >