From nobody Mon Feb 9 05:52:07 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0FBEC7EE22 for ; Thu, 18 May 2023 11:07:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230443AbjERLHs (ORCPT ); Thu, 18 May 2023 07:07:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230417AbjERLHp (ORCPT ); Thu, 18 May 2023 07:07:45 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C92F010E6 for ; Thu, 18 May 2023 04:07:43 -0700 (PDT) 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 65B37113E; Thu, 18 May 2023 04:08:28 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0D3093F793; Thu, 18 May 2023 04:07:41 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , SeongJae Park , Christoph Hellwig Cc: Ryan Roberts , "Matthew Wilcox (Oracle)" , "Kirill A. Shutemov" , Lorenzo Stoakes , Uladzislau Rezki , Zi Yan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, damon@lists.linux.dev Subject: [PATCH v2 3/5] mm: Fix failure to unmap pte on highmem systems Date: Thu, 18 May 2023 12:07:25 +0100 Message-Id: <20230518110727.2106156-4-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230518110727.2106156-1-ryan.roberts@arm.com> References: <20230518110727.2106156-1-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The loser of a race to service a pte for a device private entry in the swap path previously unlocked the ptl, but failed to unmap the pte. This only affects highmem systems since unmapping a pte is a noop on non-highmem systems. Fixes: 16ce101db85d ("mm/memory.c: fix race when faulting a device private = page") Signed-off-by: Ryan Roberts Reviewed-by: Zi Yan Reviewed-by: Mike Rapoport (IBM) --- mm/memory.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index f69fbc251198..ed429e20a1bb 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3728,10 +3728,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) vmf->page =3D pfn_swap_entry_to_page(entry); vmf->pte =3D pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); - if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { - spin_unlock(vmf->ptl); - goto out; - } + if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) + goto unlock; =20 /* * Get a page reference while we know the page can't be --=20 2.25.1