From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 84C7B53B60B for ; Wed, 23 Sep 2026 18:44:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790189102; cv=none; b=LRITU+BQlSBCEoLBui4iUQrfXRPAh17WlY8vpwhOdb2qGAQSew30VbdJF+zLbRRHWJqOqInUAYCJCF7Cd52ROexDT192iRNnzDsN4RyjZDLrl42VwXJBXFbPerHthVFnpsY7ruEThjnF8UB7u671ADrbWHlu4W49YeYvN1NMBI8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790189102; c=relaxed/simple; bh=+DPEs1Ijlmh8iE64iIZBRW5F10R8V4bZLiA7cxdGUP0=; h=Date:To:From:Subject:Message-Id; b=lR+K+vhaCShn6jCT8iBFlMkV3lAmj252UaHWfEKjU2hnLR7MBskmVG7VBazDjjELU0PHBH4OInc/hQJrYWngNVMJT1gt575+svOCK/stXuYT62TaPkjou86C0Y/Y03+2QCE9R5JoeLpEUlNT4Hcbu3EjmwMl3M7KRu2a6hNdBWY= 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=15diY+m0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="15diY+m0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9515E1F00898; Wed, 23 Sep 2026 18:44:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790189094; bh=Se61cEVPxuKkp3Z536kOKudQlOoXEJ7FXS9mXOrFEAE=; h=Date:To:From:Subject; b=15diY+m0Ocjo/XTBCuEVje3QMmy+dFHvBjF7mZ2rDl5qwXEftsi2qyo4ietQj0FBW /LtlMPZUfpOPYndHKXfdf/1NOpU+oj3Y1HqrD3uRnk88YpCuynorAwLQ3mO/yXm4Tc 5eicn/Y832CnEdYjcEZj3tEYOOQrQkQHW53vQkkI= Date: Wed, 23 Sep 2026 11:44:54 -0700 To: mm-commits@vger.kernel.org,yeoreum.yun@arm.com,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] kselftest-mm-fix-intermittent-failure-khugepaged-test.patch removed from -mm tree Message-Id: <20260923184454.9515E1F00898@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: kselftest: mm: fix intermittent failure khugepaged test has been removed from the -mm tree. Its filename was kselftest-mm-fix-intermittent-failure-khugepaged-test.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Yeoreum Yun Subject: kselftest: mm: fix intermittent failure khugepaged test Date: Mon, 21 Sep 2026 11:35:02 +0100 There are intermittent failures in collapse_max_ptes_swap() and collapse_max_ptes_shared() when using the khugepaged_context: // while running ./khugepaged -s 2 # Run test: collapse_max_ptes_shared (khugepaged:anon) # Allocate huge page... OK # Share huge page over fork()... OK # Trigger CoW on page 1023 of 2048... OK # Maybe collapse with max_ptes_shared exceeded.... OK # Trigger CoW on page 1024 of 2048... Fail Bail out! Unexpected huge page # Planned tests != run tests (26 != 23) # Totals: pass:23 fail:0 xfail:0 xpass:0 skip:0 error:0 # Run test: collapse_max_ptes_swap (khugepaged:anon) # Swapout 257 of 2048 pages... OK # Maybe collapse with max_ptes_swap exceeded.... OK # Swapout 256 of 2048 pages... OK Bail out! Unexpected huge page # Planned tests != run tests (26 != 17) # Totals: pass:17 fail:0 xfail:0 xpass:0 skip:0 error:0 This happens because khugepaged may collapse the pages before wait_for_scan() is called, causing a sanity check that expects uncollapsed pages to fail. For example, in collapse_max_ptes_swap(), after faulting the pages back in and paging out up to max_ptes_swap pages, khugepaged may collapse them again before c->collapse() is called. To prevent this, mark the VMA with MADV_NOHUGEPAGE after it has been collapsed by wait_for_scan() for anon. This prevents khugepaged from collapsing it again before c->collapse() is called. This failure was observed on NVIDIA Spark with 16KB page. Link: https://lore.kernel.org/20260921-fix_khugepagd_fail-v2-2-3c2877beef61@arm.com Signed-off-by: Yeoreum Yun Signed-off-by: Andrew Morton Reviewed-by: Baolin Wang Tested-by: Baolin Wang Cc: Zi Yan Cc: Liam Howlett Cc: Nico Pache (Red Hat) Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lance Yang Cc: Usama Arif Cc: Kirill A. Shutemov Cc: Lorenzo Stoakes (ARM) Cc: "Vlastimil Babka (SUSE)" Cc: "Mike Rapoport (IBM)" Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: David Hildenbrand (ARM) Cc: Shuah Khan (Samsung OSG) --- tools/testing/selftests/mm/khugepaged.c | 3 +++ 1 file changed, 3 insertions(+) --- a/tools/testing/selftests/mm/khugepaged.c~kselftest-mm-fix-intermittent-failure-khugepaged-test +++ a/tools/testing/selftests/mm/khugepaged.c @@ -618,6 +618,9 @@ static bool wait_for_scan(const char *ms usleep(TICK); } + if (!strncmp(ops->name, "anon", 4)) + madvise(p, len, MADV_NOHUGEPAGE); + return timeout == -1; } _ Patches currently in -mm which might be from yeoreum.yun@arm.com are kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions.patch kselftest-mm-remove-exclusion-of-building-soft-dirty-test-in-arm64.patch