From mboxrd@z Thu Jan 1 00:00:00 1970 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 181EFC2D0CD for ; Thu, 15 May 2025 06:53:41 +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: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:In-Reply-To:References:List-Owner; bh=eQcVc8m4pHheQNVrHz0HjPKBmGEh25AttjDsh3mi2ys=; b=cB/ucR4Y8LZeKYH2NQ+xCKacB6 xsaBqvGiUzyb910aP9NKr5S3T6FRtnxA1Q1jwEaE8tfkmu5U0quyUpRt4hSVqiPOn35mAfKIvQVob WHLEnlgPl4lqsySHmPgmRud+Tf56A3NyGydhbWjGXYfsRulikDk+JfmQDJfAzChHUefTKjF2w4SYQ Qi9CRm0bAAL0uHCY0ekZKBj3iTVcU5YN7RhPGSdjGfTe69bw5P0PAXJhx73GeM6wFxyFBFIrsqvNx hbP4WaTFULJOHFS7fB8Okgb1WdDpB5BRiOyK+fiFKmd9wiUT76VMPMExtiLuOZVR3lYR8jtjGpXcq CVowwECw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uFSTF-0000000HCGJ-1FEI; Thu, 15 May 2025 06:53:33 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uFSBL-0000000HA6m-1iUO for linux-arm-kernel@lists.infradead.org; Thu, 15 May 2025 06:35:05 +0000 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 49B50113E; Wed, 14 May 2025 23:34:48 -0700 (PDT) Received: from K4MQJ0H1H2.emea.arm.com (K4MQJ0H1H2.blr.arm.com [10.162.40.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 156673F673; Wed, 14 May 2025 23:34:55 -0700 (PDT) From: Dev Jain To: catalin.marinas@arm.com, will@kernel.org Cc: david@redhat.com, ryan.roberts@arm.com, anshuman.khandual@arm.com, mark.rutland@arm.com, yang@os.amperecomputing.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Dev Jain , stable@vger.kernel.org Subject: [PATCH] arm64: Check pxd_leaf() instead of !pxd_table() while tearing down page tables Date: Thu, 15 May 2025 12:04:50 +0530 Message-Id: <20250515063450.86629-1-dev.jain@arm.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250514_233503_494728_F39DA4BC X-CRM114-Status: GOOD ( 10.58 ) 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 Commit 9c006972c3fe removes the pxd_present() checks because the caller checks pxd_present(). But, in case of vmap_try_huge_pud(), the caller only checks pud_present(); pud_free_pmd_page() recurses on each pmd through pmd_free_pte_page(), wherein the pmd may be none. Thus it is possible to hit a warning in the latter, since pmd_none => !pmd_table(). Thus, enforce these checks again through pxd_leaf(). This problem was found by code inspection. The patch is based on 6.15-rc6. Fixes: 9c006972c3fe (arm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()) Cc: Reported-by: Ryan Roberts Signed-off-by: Dev Jain --- arch/arm64/mm/mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ea6695d53fb9..3d6789413a9b 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1255,7 +1255,7 @@ int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) pmd = READ_ONCE(*pmdp); - if (!pmd_table(pmd)) { + if (pmd_leaf(pmd)) { VM_WARN_ON(1); return 1; } @@ -1276,7 +1276,7 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) pud = READ_ONCE(*pudp); - if (!pud_table(pud)) { + if (pud_leaf(pud)) { VM_WARN_ON(1); return 1; } -- 2.30.2