From nobody Fri Dec 19 17:01:25 2025 Received: from mail-pg1-f179.google.com (mail-pg1-f179.google.com [209.85.215.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C31F91CE710 for ; Wed, 4 Sep 2024 08:42:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.179 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725439325; cv=none; b=eGsHFPSvqQbdixKRzCJz5cu50H+va9aVdJSnJUo922yFcxZaZ76mUca+MlaFe2ZD8Q6mYb1qu5J9CdKEnzKTum+ENgC64GLD5VXzZD439O/py/0REwlv5d2GFJIl7PR0n0IQ545MdbVvwm10IfIdxzNkRbS0+iGFIk8PuQvdhaI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725439325; c=relaxed/simple; bh=My0ULxrplZDhPoFxWfT7wAiiLVrqrf3pw9vNGA5BsnY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=acrqVUWYEuvFTqjw0zGVk+No5BxlPzaTN0wfypY4cFhcsFURh/D4PTOLsapthSlMPurRVthQP8uAMo1ouhSEzigQHszXPimbc0G1b7ZNcR9O2dhsKBarSvgLar1lT99HNWEsuW+in6zp5UijqD/h6b9CyFmWSoM+Zqvj1giB59Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com; spf=pass smtp.mailfrom=bytedance.com; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b=PxaWHlwc; arc=none smtp.client-ip=209.85.215.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bytedance.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="PxaWHlwc" Received: by mail-pg1-f179.google.com with SMTP id 41be03b00d2f7-7cd830e0711so369084a12.0 for ; Wed, 04 Sep 2024 01:42:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1725439323; x=1726044123; darn=vger.kernel.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=Y4jsyz9eZnVjuIeNrv9jm5llMD04VewCinfUm/XXhZs=; b=PxaWHlwcQMfnGVtS0De19fRNHa77B+kN35uTq9FgFz51Ml5DgmmfN6g2Sv2eTwOdU/ aVeIHP6JaulxMTFkeby8oxSRtMWwQhn4rt7oLZVPla877uYE+lVMaEqO3P1l9CjosthR DnKwTbJ8YDuDkIgtyWbWeGNdwWqlSZ/wrMENCOamHQ1mAdAysg/+no1VmgyrrcTXmycu qrd1EQRll7rspN0fmaAReA0qJXk2FbqJ9MZAqsiKjsaBv5uVFmgrVKnTNUZrCydUh2Lv qY399+DopwYaoEkY0B38oILYqVhvUub9vn5OOX6rDxsXVdeQKQGSNJab/H21Mh0NaPiv OTgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725439323; x=1726044123; 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=Y4jsyz9eZnVjuIeNrv9jm5llMD04VewCinfUm/XXhZs=; b=oQP+qMiYJYPc+3o/IYtMucb1U5kG6DG4HcAC+Oxyftcq8wUSQlhm7fP8cfjkicoaAH PkD9ik5qmXm0fHRC+Q3MT4kqczk/rcacuV3sirV+F0WEsBU10eZgMhM009zEe2TswBnr P73cb4+gbzp+ex9a/++d4TQ2Z0ifnCofLtF/CpHwmOOS3p3x+DCykaVi8y8fjtV8iJlL GtyhHyquQldIoGNrjmiZbogkIyNgLxlrC56qbKTBYBmEf8EQctK+oqsso3Cul9/C0ZQ4 NS4mqM80zeUeWySlSV3eaeJwX6vA3Dx3ilrS0Iy+kTmcyY4nwSXOqZOCdL0ZHZfZwWXC SPnA== X-Gm-Message-State: AOJu0YxbZRkMMlEn+WJxTyFpzBlrur8bW1lpiR5YbhyVTOFo/Lg4ifet AuknFX1rsLsqi4Fj65ztn1J+H2xasZl+A1tSn6qP7qJENkHm8Wck8lx2w2BnTME= X-Google-Smtp-Source: AGHT+IGXU/qy5PPe2L4ehUmGkYFpO+LVdbh/09mdfTo5RpVJKjaH3T6TEVRYBI0feUcEJkjAodGgeA== X-Received: by 2002:a17:902:e545:b0:1fd:6ca4:f987 with SMTP id d9443c01a7336-206b8341fdfmr24676655ad.15.1725439323059; Wed, 04 Sep 2024 01:42:03 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([139.177.225.242]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-206ae95a51csm9414045ad.117.2024.09.04.01.41.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Sep 2024 01:42:02 -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, christophe.leroy2@cs-soprasteria.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 v3 12/14] mm: multi-gen LRU: walk_pte_range() use pte_offset_map_rw_nolock() Date: Wed, 4 Sep 2024 16:40:20 +0800 Message-Id: <20240904084022.32728-13-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20240904084022.32728-1-zhengqi.arch@bytedance.com> References: <20240904084022.32728-1-zhengqi.arch@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In walk_pte_range(), we may modify the pte entry after holding the ptl, so convert it to using pte_offset_map_rw_nolock(). At this time, the pte_same() check is not performed after the ptl held, so we should get pmdval and do pmd_same() check to ensure the stability of pmd entry. Signed-off-by: Qi Zheng Reviewed-by: Muchun Song --- mm/vmscan.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index a9b6a8196f958..36b84e46cd7b5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3375,8 +3375,10 @@ static bool walk_pte_range(pmd_t *pmd, unsigned long= start, unsigned long end, struct pglist_data *pgdat =3D lruvec_pgdat(walk->lruvec); DEFINE_MAX_SEQ(walk->lruvec); int old_gen, new_gen =3D lru_gen_from_seq(max_seq); + pmd_t pmdval; =20 - pte =3D pte_offset_map_nolock(args->mm, pmd, start & PMD_MASK, &ptl); + pte =3D pte_offset_map_rw_nolock(args->mm, pmd, start & PMD_MASK, &pmdval, + &ptl); if (!pte) return false; if (!spin_trylock(ptl)) { @@ -3384,6 +3386,11 @@ static bool walk_pte_range(pmd_t *pmd, unsigned long= start, unsigned long end, return false; } =20 + if (unlikely(!pmd_same(pmdval, pmdp_get_lockless(pmd)))) { + pte_unmap_unlock(pte, ptl); + return false; + } + arch_enter_lazy_mmu_mode(); restart: for (i =3D pte_index(start), addr =3D start; addr !=3D end; i++, addr += =3D PAGE_SIZE) { --=20 2.20.1