From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CE23F606A322 for ; Wed, 28 Oct 2026 15:54:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=GoZfFHcc; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=bIPJgOc3 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc: To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=tTZpPE9gJn7s96098K7j6uvB27YaMf32yiUhWF9ATX4=; b=GoZfFHcczoTnKr wSj3gmaWN3x97dNNadql+D9AByxQRNRdNQR+rqgj4sReG+pw5jksbRAcQWE3dLSqbeKQMhO3O0yiy HDiULqgg2mGxC0M1zCZG6ySnkerogLb5PetWm385dFJJK1ES1B/IzKcHsktqCLe7jJLyDH+vhB0X1 PrCybs7uyS+MrFb5kneuo+cxiXcnJN0BM6c0zQLbkAoA+LMxJGSpZvkkgQRFnrre+JPgFH/RJTqCz I9OCJ/2Kkk1M8/6aSujSJhdHqCkyF7o2Ez8ZszFLhu4qOKW+sHlyMKqiK9LMWlxRaD85M7SEb/r3q 91RlQ8ayHCOpDF6WMIiQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xM5yq-00000007TFR-2uLx; Wed, 28 Oct 2026 15:54:24 +0000 Received: from out-54.mta1.migadu.com ([95.215.58.54] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xM5yn-00000007TEW-3TTk for kexec@lists.infradead.org; Wed, 28 Oct 2026 15:54:23 +0000 X-Envelope-To: kexec@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=tTZpPE9gJn7s96098K7j6uvB27YaMf32yiUhWF9ATX4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793202859; v=1; x=1793807659; b=bIPJgOc3iPcKTa1DXojN+YH2KEJcCalwAlquT1K3q2vP78rezERhjcEiyPnYf3XJJi+zm40e VZ8Y7h0Sg0LHwZ3RIB6hSZlxVJqtHyTLtmTMwa/Q5NiV5ZlDRHprLtwNr+zvun7UOnbjrZLyZOI 1EXHQla+Wo0nAnoYaUtKJ62U= X-Envelope-To: kexec@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id f81f3d53b1ebb019; Wed, 28 Oct 2026 15:54:18 +0000 X-Mizu-Trace-ID: f81f3d53b1ebb019 X-Migadu-Flow: FLOW_OUT From: Lance Yang To: david@kernel.org Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@kernel.org, qi.zheng@linux.dev, shakeel.butt@linux.dev, ljs@kernel.org, kasong@tencent.com, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, baoquan.he@linux.dev, baolin.wang@linux.alibaba.com, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, kees@kernel.org, peterz@infradead.org, jannh@google.com, pfalcato@suse.de, hughd@google.com, pasha.tatashin@soleen.com, pratyush@kernel.org, willy@infradead.org, jack@suse.cz, ziy@nvidia.com, lance.yang@linux.dev, riel@surriel.com, harry@kernel.org, apopple@nvidia.com, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, usama.arif@linux.dev, kas@kernel.org, matthew.brost@intel.com, jhubbard@nvidia.com, peterx@redhat.com, will@kernel.org, aneesh.kumar@kernel.org, npiggin@gmail.com, osalvador@suse.de, minchan@kernel.org, muchun.song@linux.dev, xu.xin@linux.dev, chengming.zhou@linux.dev, chrisl@kernel.org, shikemeng@huaweicloud.com, nphamcs@gmail.com, youngjun.park@lge.com, gourry@gourry.net, joshua.hahnjy@gmail.com, rakie.kim@sk.com, ying.huang@linux.alibaba.com, jgg@ziepe.ca, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, mason@kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 13/46] mm/huge_memory: fix truncate racing with PMD zapping Date: Wed, 28 Oct 2026 23:54:11 +0800 Message-ID: <20261028155411.50458-1-lance.yang@linux.dev> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20261027-fixes_core-v1-13-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-13-6f74bec9a5bb@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261028_085422_008677_86F4DA17 X-CRM114-Status: UNSURE ( 6.87 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.1 (--) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" X-Spam-Status: No, score=-13.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Oct 27, 2026 at 12:17:33AM +0100, David Hildenbrand (Arm) wrote: >From: Chris Mason > >zap_huge_pmd_folio() removes the rmap before calling folio_mark_dirty(). >If this was the last mapping, truncation can skip unmapping the folio >and proceed without waiting for the PMD lock, racing with dirtying. > >ifs_set_range_dirty() can oops if MADV_DONTNEED races with >ftruncate() on XFS, when we get the folio set dirty after it was found >to not be mapped anymore. > >Move folio_mark_dirty() and folio_mark_accessed() before rmap removal, >matching the PTE zap path. This keeps the folio mapped while updating >its state, so truncation must wait for the page table lock. > >Fix generated by an LLM and sent by Chris Mason in private. > >Fixes: fe6cf984939d ("mm/huge_memory: transfer the pmd dirty bit to the folio on zap") >Cc: stable@vger.kernel.org >Signed-off-by: Chris Mason >[ david: simplify comment and description ] >Signed-off-by: David Hildenbrand (Arm) >--- Good catch! Reviewed-by: Lance Yang