From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB19E63A9; Mon, 6 May 2024 00:28:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714955333; cv=none; b=qYhatX7pwns/PDwcwKeC4JLR0w3d6C5V2iGNkmDf9xyT4KgqBIiJVj3nyoGd6lsubfPQfcevUQHaDLHOJ3F/2ip5oGsjp5ENBBww4n7bOpVOXqyT7iP8mGwlF0SU+hsKk25KAvQW2BvVbDFegdyXdzUk63ZUT3EeHkvJJSqeAx0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714955333; c=relaxed/simple; bh=KXngUfJs0V7NMa+eja4yavbvwn7lF6m4cNk/uXBNqOw=; h=Date:To:From:Subject:Message-Id; b=pJRGaK5Y3EFjWfkHu1Ozn0jqvyAKSjZeRfzzekj+gM8hCpjXh+zX/H1Tfgv+m357UFD/MKXMwTrjk20UJ9CNa1dIcBISNmCPsVqwnirC5UC7rp7/qZY/9otDnUFEecd7lwWBT1ikZFBnss0GxS7OUHTO+7XLMCkyFL6IC2GxGms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=JvGJ8zsl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="JvGJ8zsl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFE56C113CC; Mon, 6 May 2024 00:28:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1714955332; bh=KXngUfJs0V7NMa+eja4yavbvwn7lF6m4cNk/uXBNqOw=; h=Date:To:From:Subject:From; b=JvGJ8zsloKK2QsdPWI0KEKVcs6ZOEOu0Zs00Mm6J7QWxde9RCcwR7mld25X+votxe zmdwDdIB7mcSnwUEd6I4+d8H6dG/CO4WgjaCsM42LQTdPzbk0NugURSr9ATDwwkKmL VKqz6DZX1oyb5BJAZLjAf7D+3LqoSnIiiXaDaf/Q= Date: Sun, 05 May 2024 17:28:52 -0700 To: mm-commits@vger.kernel.org,usama.anjum@collabora.com,stable@vger.kernel.org,peterx@redhat.com,david@redhat.com,ryan.roberts@arm.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] fs-proc-task_mmu-fix-uffd-wp-confusion-in-pagemap_scan_pmd_entry.patch removed from -mm tree Message-Id: <20240506002852.AFE56C113CC@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: fs/proc/task_mmu: fix uffd-wp confusion in pagemap_scan_pmd_entry() has been removed from the -mm tree. Its filename was fs-proc-task_mmu-fix-uffd-wp-confusion-in-pagemap_scan_pmd_entry.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Ryan Roberts Subject: fs/proc/task_mmu: fix uffd-wp confusion in pagemap_scan_pmd_entry() Date: Mon, 29 Apr 2024 12:41:04 +0100 pagemap_scan_pmd_entry() checks if uffd-wp is set on each pte to avoid unnecessary if set. However it was previously checking with `pte_uffd_wp(ptep_get(pte))` without first confirming that the pte was present. It is only valid to call pte_uffd_wp() for present ptes. For swap ptes, pte_swp_uffd_wp() must be called because the uffd-wp bit may be kept in a different position, depending on the arch. This was leading to test failures in the pagemap_ioctl mm selftest, when bringing up uffd-wp support on arm64 due to incorrectly interpretting the uffd-wp status of migration entries. Let's fix this by using the correct check based on pte_present(). While we are at it, let's pass the pte to make_uffd_wp_pte() to avoid the pointless extra ptep_get() which can't be optimized out due to READ_ONCE() on many arches. Link: https://lkml.kernel.org/r/20240429114104.182890-1-ryan.roberts@arm.com Fixes: 12f6b01a0bcb ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag") Closes: https://lore.kernel.org/linux-arm-kernel/ZiuyGXt0XWwRgFh9@x1n/ Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand Reviewed-by: Muhammad Usama Anjum Tested-by: Muhammad Usama Anjum Cc: Peter Xu Cc: Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) --- a/fs/proc/task_mmu.c~fs-proc-task_mmu-fix-uffd-wp-confusion-in-pagemap_scan_pmd_entry +++ a/fs/proc/task_mmu.c @@ -1817,10 +1817,8 @@ static unsigned long pagemap_page_catego } static void make_uffd_wp_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t *pte) + unsigned long addr, pte_t *pte, pte_t ptent) { - pte_t ptent = ptep_get(pte); - if (pte_present(ptent)) { pte_t old_pte; @@ -2175,9 +2173,12 @@ static int pagemap_scan_pmd_entry(pmd_t if ((p->arg.flags & PM_SCAN_WP_MATCHING) && !p->vec_out) { /* Fast path for performing exclusive WP */ for (addr = start; addr != end; pte++, addr += PAGE_SIZE) { - if (pte_uffd_wp(ptep_get(pte))) + pte_t ptent = ptep_get(pte); + + if ((pte_present(ptent) && pte_uffd_wp(ptent)) || + pte_swp_uffd_wp_any(ptent)) continue; - make_uffd_wp_pte(vma, addr, pte); + make_uffd_wp_pte(vma, addr, pte, ptent); if (!flush_end) start = addr; flush_end = addr + PAGE_SIZE; @@ -2190,8 +2191,10 @@ static int pagemap_scan_pmd_entry(pmd_t p->arg.return_mask == PAGE_IS_WRITTEN) { for (addr = start; addr < end; pte++, addr += PAGE_SIZE) { unsigned long next = addr + PAGE_SIZE; + pte_t ptent = ptep_get(pte); - if (pte_uffd_wp(ptep_get(pte))) + if ((pte_present(ptent) && pte_uffd_wp(ptent)) || + pte_swp_uffd_wp_any(ptent)) continue; ret = pagemap_scan_output(p->cur_vma_category | PAGE_IS_WRITTEN, p, addr, &next); @@ -2199,7 +2202,7 @@ static int pagemap_scan_pmd_entry(pmd_t break; if (~p->arg.flags & PM_SCAN_WP_MATCHING) continue; - make_uffd_wp_pte(vma, addr, pte); + make_uffd_wp_pte(vma, addr, pte, ptent); if (!flush_end) start = addr; flush_end = next; @@ -2208,8 +2211,9 @@ static int pagemap_scan_pmd_entry(pmd_t } for (addr = start; addr != end; pte++, addr += PAGE_SIZE) { + pte_t ptent = ptep_get(pte); unsigned long categories = p->cur_vma_category | - pagemap_page_category(p, vma, addr, ptep_get(pte)); + pagemap_page_category(p, vma, addr, ptent); unsigned long next = addr + PAGE_SIZE; if (!pagemap_scan_is_interesting_page(categories, p)) @@ -2224,7 +2228,7 @@ static int pagemap_scan_pmd_entry(pmd_t if (~categories & PAGE_IS_WRITTEN) continue; - make_uffd_wp_pte(vma, addr, pte); + make_uffd_wp_pte(vma, addr, pte, ptent); if (!flush_end) start = addr; flush_end = next; _ Patches currently in -mm which might be from ryan.roberts@arm.com are selftests-mm-soft-dirty-should-fail-if-a-testcase-fails.patch mm-debug_vm_pgtable-test-pmd_leaf-behavior-with-pmd_mkinvalid.patch mm-fix-race-between-__split_huge_pmd_locked-and-gup-fast.patch