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 73E673B1AB; Wed, 5 Jun 2024 22:04:08 +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=1717625049; cv=none; b=QIC+26P9zd5+lZZCaakB0D1rQIYL2MAEmDBvHSeEnyzoRjcZbFEaWLenRfaFdn8pT6dtT8YujPz9K4ObFjOU0KCyQENEE08UiUqkuHfkA7Ze/+V23HBLpzTPWaoE9uAxYGnB4NRfYc101qB5Jvx92fKwlZIWk1MEBbIZSJj/mKY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717625049; c=relaxed/simple; bh=RZioaYMJPvPZnCV3Q6RXiVh/YaDF6STFZSTPUk9xEZE=; h=Date:To:From:Subject:Message-Id; b=MvRS2ZlDY6l+hs//l7zCB85wXXehy1/XbC866v0uvi1FcVToZdFL64b4wRA5SGgSGJMjgKoX7cMcqxCTMsVlQIx2UUYoGfF0mkHeUGjxhXYiPKD7Q5eFCEyiiujmnhOp1kXH7DvYjDf1FRsSDBjcPpg2UMKWGkMHAMEgRhLhxfE= 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=gdB+LAMF; 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="gdB+LAMF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9192FC2BD11; Wed, 5 Jun 2024 22:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1717625048; bh=RZioaYMJPvPZnCV3Q6RXiVh/YaDF6STFZSTPUk9xEZE=; h=Date:To:From:Subject:From; b=gdB+LAMFeEc7OqgAnLfrE+GCYfGH0eR6JSQXPTI9DCPUIHrcHwieucIONtO34Pdst bGpnJS1AF1+bRJDyYNuUeLqGegCTwtKt/x/Iy5TIJTdYebklDZqN0O/RVc+rjL8Sb8 kYw878CQi/S9hv0MQgYmzF/h22+1YsSkvJzsQg1Y= Date: Wed, 05 Jun 2024 15:04:07 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,pasha.tatashin@soleen.com,dan.j.williams@intel.com,peterx@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-page_table_check-fix-crash-on-zone_device.patch added to mm-hotfixes-unstable branch Message-Id: <20240605220408.9192FC2BD11@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/page_table_check: fix crash on ZONE_DEVICE has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-page_table_check-fix-crash-on-zone_device.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_table_check-fix-crash-on-zone_device.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Peter Xu Subject: mm/page_table_check: fix crash on ZONE_DEVICE Date: Wed, 5 Jun 2024 17:21:46 -0400 Not all pages may apply to pgtable check. One example is ZONE_DEVICE pages: they map PFNs directly, and they don't allocate page_ext at all even if there's struct page around. One may reference devm_memremap_pages(). When both ZONE_DEVICE and page-table-check enabled, then try to map some dax memories, one can trigger kernel bug constantly now when the kernel was trying to inject some pfn maps on the dax device: kernel BUG at mm/page_table_check.c:55! While it's pretty legal to use set_pxx_at() for ZONE_DEVICE pages for page fault resolutions, skip all the checks if page_ext doesn't even exist in pgtable checker, which applies to ZONE_DEVICE but maybe more. Link: https://lkml.kernel.org/r/20240605212146.994486-1-peterx@redhat.com Signed-off-by: Peter Xu Cc: Dan Williams Cc: Pasha Tatashin Cc: Signed-off-by: Andrew Morton --- mm/page_table_check.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/mm/page_table_check.c~mm-page_table_check-fix-crash-on-zone_device +++ a/mm/page_table_check.c @@ -73,6 +73,9 @@ static void page_table_check_clear(unsig page = pfn_to_page(pfn); page_ext = page_ext_get(page); + if (!page_ext) + return; + BUG_ON(PageSlab(page)); anon = PageAnon(page); @@ -110,6 +113,9 @@ static void page_table_check_set(unsigne page = pfn_to_page(pfn); page_ext = page_ext_get(page); + if (!page_ext) + return; + BUG_ON(PageSlab(page)); anon = PageAnon(page); @@ -140,7 +146,10 @@ void __page_table_check_zero(struct page BUG_ON(PageSlab(page)); page_ext = page_ext_get(page); - BUG_ON(!page_ext); + + if (!page_ext) + return; + for (i = 0; i < (1ul << order); i++) { struct page_table_check *ptc = get_page_table_check(page_ext); _ Patches currently in -mm which might be from peterx@redhat.com are mm-page_table_check-fix-crash-on-zone_device.patch mm-debug_vm_pgtable-drop-random_orvalue-trick.patch mm-drop-leftover-comment-references-to-pxx_huge.patch