From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831808; b=b2TI1YsMwgm1rNS6dX5dMgFJ6ed2o1HBqYdyA1KP9kZtjts3DccGJK0QRuE9iLD0HwW9 dElvJmjrSSW3v/odRGRRsbVnSAqEdpZLUQYW3Bw9wxXdjb1WQgA30L6uA+7XkiW3clQKw Afm6E8vhUIECDSeZcLokVYVhFI2j4m4qbus/vWw8/ivXvSeEOogA81FAUUQElzqF8UWBF viQzfs306gDn9gl2rAMf8wIByMZTnEGf56C5wAkRQ5nb/8P7ex2lQvuKwVkRfmqVh4P0L bCija5I/5358kQiT2FL7mcwNfHOigImjs4Ui1bzb/wpm/qiD9kKb2j7yJq4wePJEYQg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831808; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=/QZpiuOF1IqIVVOiuXpKoO1PhvYx5cUt6Z0EiGAc+SI=; b=ZfePnvMOYpe4e/EbPIsouduzj3jZaOHdpOLRktZZ8FtFpogJsDO5k30Kr615Yv/Y4Pzt LEqiG8ab6vnPkOTl6gwk6Bmw9yGNVRb6idA4m2S4TdFpvI50lFgxAamGOmvfOOvNG0ZgU x/amOozQI24xOYqDN/z3iIC70fYajZ7DsMCqGeAATwEkgfMWpQNHMWOzI6LDZUdAfF0S+ GJM9H6hkh5GBciyzovEO8m7N/NhBm4EAE7wWgGhhnbSrfGvLVp4ZuCn2sN8JioOWJXP+i PlkgdYhEzdaH565zZRjjT/sax1KqRaFlQ7qaf+6FD0SJvytyLd+rjUhcrC+bFd56u1w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=rnTvTe3I; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9432D606A33D; Wed, 4 Nov 2026 22:36:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=rnTvTe3I Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41FF81F000C1; Wed, 4 Nov 2026 22:36:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831808; bh=/QZpiuOF1IqIVVOiuXpKoO1PhvYx5cUt6Z0EiGAc+SI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rnTvTe3IePh0j6ZslZtj8yu/2cdgDe4FGSCqrlnUQrDn8twe/oB9PLkRV9UfDtuGM hRUWm3J2k7Qjx1XnHO/fhkRABbKiRb7dQYRbYBPxLuBeOsqq8fjoih7aLXVJn0rFoR mQTwNXLuleLfsruwx1IVNT9o2/7B0OP6ew/ig7I0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Mike Rapoport (Microsoft)" , Dave Hansen , Juergen Gross , "Lorenzo Stoakes (ARM)" , syzbot@syzkaller.appspotmail.com, Atish Patra , Nikunj A Dadhania Subject: [PATCH 6.18 0924/1005] x86/mm/pat: Fix effective RW computation in lookup_address_in_pgd_attr() Date: Wed, 4 Nov 2026 16:10:57 -0500 Message-ID: <20261104211109.026460924@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Rapoport (Microsoft) commit ebaf7c9bbb1e16523d7036e7e1225ad2dfcc6482 upstream. lookup_address_in_pgd_attr() accumulates the effective NX and RW bits of the walked page table levels so that verify_rwx() can detect mappings that are both writable and executable. The RW bits are folded into a bool with rw &= pXd_flags(*pXd) & _PAGE_RW; but _PAGE_RW is 0x2. So consider the accumulation line: rw &= pXd_flags(*pXd) & _PAGE_RW; where rw=0x1 and the right side evaluates down to 0x2. It'll end up doing: rw = 0x1 & 0x2 and rw always ends up 0. This way rw becomes false at the first level walked, regardless of the actual permissions, and verify_rwx() treats every mapping as non-writable and never reports a W^X violation. Add double negation to the right side to normalize the _PAGE_RW flag to 0 or 1. Assisted-by: Copilot:claude-opus-4.8 Fixes: ceb647b4b529 ("x86/pat: Introduce lookup_address_in_pgd_attr()") Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Dave Hansen Reviewed-by: Juergen Gross Reviewed-by: Lorenzo Stoakes (ARM) Tested-by: syzbot@syzkaller.appspotmail.com Tested-by: Atish Patra Tested-by: Nikunj A Dadhania Cc:stable@vger.kernel.org Link: https://patch.msgid.link/20260813-cpa-fixes-v2-5-39b4ff90f91d@kernel.org Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/pat/set_memory.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -753,7 +753,7 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *level = PG_LEVEL_512G; *nx |= pgd_flags(*pgd) & _PAGE_NX; - *rw &= pgd_flags(*pgd) & _PAGE_RW; + *rw &= !!(pgd_flags(*pgd) & _PAGE_RW); p4d = p4d_offset(pgd, address); if (p4d_none(*p4d)) @@ -764,7 +764,7 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *level = PG_LEVEL_1G; *nx |= p4d_flags(*p4d) & _PAGE_NX; - *rw &= p4d_flags(*p4d) & _PAGE_RW; + *rw &= !!(p4d_flags(*p4d) & _PAGE_RW); pud = pud_offset(p4d, address); if (pud_none(*pud)) @@ -775,7 +775,7 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *level = PG_LEVEL_2M; *nx |= pud_flags(*pud) & _PAGE_NX; - *rw &= pud_flags(*pud) & _PAGE_RW; + *rw &= !!(pud_flags(*pud) & _PAGE_RW); pmd = pmd_offset(pud, address); if (pmd_none(*pmd)) @@ -786,7 +786,7 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *level = PG_LEVEL_4K; *nx |= pmd_flags(*pmd) & _PAGE_NX; - *rw &= pmd_flags(*pmd) & _PAGE_RW; + *rw &= !!(pmd_flags(*pmd) & _PAGE_RW); return pte_offset_kernel(pmd, address); }