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[99.241.198.116]) by smtp.gmail.com with ESMTPSA id a3-20020a5ec303000000b006496b4dd21csm11386663iok.5.2022.04.20.06.32.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Apr 2022 06:32:39 -0700 (PDT) Date: Wed, 20 Apr 2022 09:32:38 -0400 From: Peter Xu To: Miaohe Lin Cc: akpm@linux-foundation.org, willy@infradead.org, vbabka@suse.cz, dhowells@redhat.com, neilb@suse.de, david@redhat.com, apopple@nvidia.com, surenb@google.com, minchan@kernel.org, sfr@canb.auug.org.au, rcampbell@nvidia.com, naoya.horiguchi@nec.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/swapfile: unuse_pte can map random data if swap read fails Message-ID: References: <20220416030549.60559-1-linmiaohe@huawei.com> <8e01e276-c956-2486-c55f-c689f33a9106@huawei.com> MIME-Version: 1.0 In-Reply-To: <8e01e276-c956-2486-c55f-c689f33a9106@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D0F43180023 X-Rspam-User: Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=VULOMg79; spf=none (imf24.hostedemail.com: domain of peterx@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=peterx@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Stat-Signature: d8doz63grc7sefou44fjz51powebxfnk X-HE-Tag: 1650461561-106765 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Apr 20, 2022 at 02:21:27PM +0800, Miaohe Lin wrote: > On 2022/4/20 5:36, Peter Xu wrote: > > On Sat, Apr 16, 2022 at 11:05:49AM +0800, Miaohe Lin wrote: > >> @@ -1797,6 +1797,17 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, > >> goto out; > >> } > >> > >> + if (unlikely(!PageUptodate(page))) { > >> + pte_t pteval; > >> + > >> + dec_mm_counter(vma->vm_mm, MM_SWAPENTS); > >> + pteval = swp_entry_to_pte(make_swapin_error_entry(page)); > >> + set_pte_at(vma->vm_mm, addr, pte, pteval); > >> + swap_free(entry); > >> + ret = 0; > >> + goto out; > >> + } > >> + > >> /* See do_swap_page() */ > >> BUG_ON(!PageAnon(page) && PageMappedToDisk(page)); > >> BUG_ON(PageAnon(page) && PageAnonExclusive(page)); > > > > Totally off-topic, but.. today when I was looking at the unuse path I just > > found that the swp bits could have got lost for either soft-dirty and > > uffd-wp here? A quick patch attached. > > Am I supposed to test-and-send this patch? The patch looks good to me except the > build error pointed out by kernel test robot. I was planning to post a patch after yours since they're touching the same function, but yeah it'll be great if you could also take that over, thanks! -- Peter Xu