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 03C50C54ED1 for ; Tue, 27 May 2025 08:45:11 +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=4hdF8NSlNiDKSW4k5s5KQn7s29HVgOVY53XC8RjHPXc=; b=Krlbu1EI5EUvCmMS43lJvgKKng m4QY5brNHLjMYnjV7lt3GBU6s+V3YlYarAwb+1aJl48NjLRAqP0ZE+IenILFw8dsJD8n4rGCF1vnV uf2R3XUAkl1ybewgKRhDAKO4dacsM7n2tihCqVJDyTt6FzwMGLEyXeznBIfHbhxTqdxjtIqgrkQ80 5nofqC6nTM5KkMUW0vqZZep/6CiKc4ZG7Nm0fnfDBXfBlTFN+sG9nS80pPg5jhyouCHabw78mWu32 Mzs4uPFVkF9G8Z0aZGxQsksVVw5LBWTSiozWi1tLFdRyx+jnYVxYmn8DJULiERirhRel4Wzo27+6B 9C2Jow1g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uJpvi-0000000AHhD-3XxV; Tue, 27 May 2025 08:45:02 +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 1uJpdy-0000000AFZc-1Mhe for linux-arm-kernel@lists.infradead.org; Tue, 27 May 2025 08:26:43 +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 6C34E14BF; Tue, 27 May 2025 01:26:25 -0700 (PDT) Received: from localhost.localdomain (unknown [10.163.85.29]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 0C2C23F5A1; Tue, 27 May 2025 01:26:37 -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 v3] arm64: Restrict pagetable teardown to avoid false warning Date: Tue, 27 May 2025 13:56:33 +0530 Message-Id: <20250527082633.61073-1-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-20250527_012642_406630_9E891125 X-CRM114-Status: UNSURE ( 9.69 ) X-CRM114-Notice: Please train this message. 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, add a pmd_present() check in pud_free_pmd_page(). This problem was found by code inspection. Fixes: 9c006972c3fe (arm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()) Cc: Reported-by: Ryan Roberts Acked-by: David Hildenbrand Signed-off-by: Dev Jain --- This patch is based on 6.15-rc6. v2->v3: - Use pmdp_get() v1->v2: - Enforce check in caller arch/arm64/mm/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ea6695d53fb9..5a9bf291c649 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1286,7 +1286,8 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) next = addr; end = addr + PUD_SIZE; do { - pmd_free_pte_page(pmdp, next); + if (pmd_present(pmdp_get(pmdp))) + pmd_free_pte_page(pmdp, next); } while (pmdp++, next += PMD_SIZE, next != end); pud_clear(pudp); -- 2.30.2