From patchwork Wed Aug 21 08:18:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13771001 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 81B65C52D6F for ; Wed, 21 Aug 2024 08:22:00 +0000 (UTC) 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: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=arLLKSkNLaMIjiTVBc0cMKPJV4f+y4Msx8WJt/66k5c=; b=emDTb3AIhwVRzU6+fiEdhKdwwc DSTv7znHjQCdRQBYMjhicEHXNhhdjyZVKFIPMJ1V75H28a0zMx/YdW1cqCgtP+eraLTFPj3BNLC3q VSCLBxRn9gmLII9pE0zAO0wu8BYOwKQHeqrdHG++4B6CUTml1d7v9hwPX/sf92MW1rNJZQ4FgkvkO +VMfIqIAvGY5TZAElCFNFeVI9u2rEUyegu7SecSV0PMMA++rj23jTXawfkfwtIEa2d2dB0X/SQ7dk 1L97s3lJBTUwt6pmToYXGG7Ff/SXFF7R8woYkgO0iKDltFAHmIlsqsUphI9UKg9t3u+JGLKj630rR RBNlDHfg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sggbG-000000082WH-47me; Wed, 21 Aug 2024 08:21:50 +0000 Received: from mail-pg1-x52c.google.com ([2607:f8b0:4864:20::52c]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sggZA-000000081mL-1eAO for linux-arm-kernel@lists.infradead.org; Wed, 21 Aug 2024 08:19:41 +0000 Received: by mail-pg1-x52c.google.com with SMTP id 41be03b00d2f7-7bcf8077742so4723022a12.0 for ; Wed, 21 Aug 2024 01:19:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1724228379; x=1724833179; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=arLLKSkNLaMIjiTVBc0cMKPJV4f+y4Msx8WJt/66k5c=; b=jvnN9L/bpXerNTA2J22EiTqRU3eL3RNrzi7sAnlbfrYr5XeDU5sMKp7fRsrzuM5djD auQLvHH6g0rzx62+hhb4ZuP/A//lMGSHlGrC8KCuxoOo3/tgE70PVlajAdizTXXJgNSB hKaIb07LC41oNcsaMCatwZKA1QmF+sni1Ix6MVqx8RHbJ3j+uw7OhLofb0Odzr7x+gTz y6KG2775JHziebTjzDMEvq+o3aguyOsFVoENGchneoTy2w//W02NkDrkG1B8tSF2UVMm A8H1MTFDQ6BxJgQhaoOZ4h/yyneZE9ToL1UwBTX2/7LGQ6669tInEuwmBEQ1z9onm4BK CNHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724228379; x=1724833179; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=arLLKSkNLaMIjiTVBc0cMKPJV4f+y4Msx8WJt/66k5c=; b=HE9XKxpdt06sBFB35nQbgrAj82t3GOCzjmPs9JIKEyGlMe8KQBeJKbfWhT0ROKkIPh ciqgnzaMz8YX1jsV/GJkKRu1NzhUKMYBAbl/UqlYGfJ6aiuTuzy1IP3DivzCHtdBCWia LuTDInAJz6+NU47YaMVGMSG6GmRqvfPNRQN/pdAF2Oc+nAr72VRIzMekLo9zE4YE3kXP 2h+vJ+qVvR85j10rxP72F7oRH4PFxmbLjLesE++3BwF6EfcQDSxzHO8r2ENGJ8eFL4HR WRR5pHk/NyZvUblAnIYgL7El/7lTo8TJ38u9osSaWwnmCgqmdInTFS53AwSL98Cn2/K5 tTug== X-Forwarded-Encrypted: i=1; AJvYcCUy8UZQzCEqXVWxE4f4wq+wlcrPHK3+XJSszaCV9Iaz2GON1kwq3zoeTNDl/v6CjWqLTtfc/6RPzJ/eM0P0BzIh@lists.infradead.org X-Gm-Message-State: AOJu0Yx0S9NRipP0+rpn8uSN2J7qENfrxZB+jt6t1yX23PFzpscMXKDq 8QMY7Doy66R5mQ3JNwaTtYWyrBGVWlSvTPRKPlN9VaiwEJXHi4MpVbaFZ2coJus= X-Google-Smtp-Source: AGHT+IEvHWRxH/KV5glvGK0Xiv2dJ13pnLs9scNXFJwmOSFepkjBPO6rW4EjBZpYY7GPQ4yq94i7jA== X-Received: by 2002:a05:6a21:168e:b0:1c4:d05c:a967 with SMTP id adf61e73a8af0-1cada179499mr1734402637.51.1724228379371; Wed, 21 Aug 2024 01:19:39 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.150]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2d5eb9049b0sm1091453a91.17.2024.08.21.01.19.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Aug 2024 01:19:38 -0700 (PDT) From: Qi Zheng To: david@redhat.com, hughd@google.com, willy@infradead.org, muchun.song@linux.dev, vbabka@kernel.org, akpm@linux-foundation.org, rppt@kernel.org, vishal.moola@gmail.com, peterx@redhat.com, ryan.roberts@arm.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Qi Zheng Subject: [PATCH 02/14] arm: adjust_pte() use pte_offset_map_maywrite_nolock() Date: Wed, 21 Aug 2024 16:18:45 +0800 Message-Id: <3d151aaf876b93a97fd3f070780345a3bf572123.1724226076.git.zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240821_011940_455140_EB328604 X-CRM114-Status: GOOD ( 12.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In do_adjust_pte(), we may modify the pte entry. At this time, the write lock of mmap_lock is not held, and the pte_same() check is not performed after the PTL held. The corresponding pmd entry may have been modified concurrently. Therefore, in order to ensure the stability if pmd entry, use pte_offset_map_maywrite_nolock() to replace pte_offset_map_nolock(), and do pmd_same() check after holding the PTL. Signed-off-by: Qi Zheng --- arch/arm/mm/fault-armv.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c index 831793cd6ff94..5371920ec0550 100644 --- a/arch/arm/mm/fault-armv.c +++ b/arch/arm/mm/fault-armv.c @@ -94,6 +94,7 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address, pud_t *pud; pmd_t *pmd; pte_t *pte; + pmd_t pmdval; int ret; pgd = pgd_offset(vma->vm_mm, address); @@ -112,16 +113,22 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address, if (pmd_none_or_clear_bad(pmd)) return 0; +again: /* * This is called while another page table is mapped, so we * must use the nested version. This also means we need to * open-code the spin-locking. */ - pte = pte_offset_map_nolock(vma->vm_mm, pmd, address, &ptl); + pte = pte_offset_map_maywrite_nolock(vma->vm_mm, pmd, address, &pmdval, &ptl); if (!pte) return 0; do_pte_lock(ptl); + if (unlikely(!pmd_same(pmdval, pmdp_get_lockless(pmd)))) { + do_pte_unlock(ptl); + pte_unmap(pte); + goto again; + } ret = do_adjust_pte(vma, address, pfn, pte);