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 93719503913 for ; Tue, 29 Sep 2026 20:28:57 +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=1790713738; cv=none; b=tx80DyF3lw+08UH2AK9ENXGVybYe21pfn1T+Ki2iSKXkUWq2VcWfUFgjqoeUF/N9j62oS4Id83QUqXgrYTj1mfv+sy26XA6FMMTqecItpUmRYGtUTHWFCX+1sIp+Tv9wPi5ItXbzd/1Sw4SHZ24QgEn86X/Ho30EcoU7/9rVYCU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790713738; c=relaxed/simple; bh=Tiaxg9VBHZjuvmpJK8gF5sPZhCvllNGAmFUxsuqcJww=; h=Date:To:From:Subject:Message-Id; b=rPfHRKY7bkrAkwE2bNdY+DPe+hNluPg0leKP3Jb9581+cVzkRnfNwqroGou05xOse7uWmn7gK9lWU1Muh2jq8I9ZZwoFzKGukvfda6bvuU9RPABgcXc3ih+ZUvAqMh1rl1ooLWdiSQ57HFdqXW1MJ5KlLUpaJajFdw9Y7ZhhVH8= 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=gwWS/23G; 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="gwWS/23G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C5A91F00893; Tue, 29 Sep 2026 20:28:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790713737; bh=Vk0JPkdWIN8zePlX+qQsT9z8+AJcUgUfylP/rY8Sgwc=; h=Date:To:From:Subject; b=gwWS/23GPyI411FO1eT856hqKVx/ymA1oOeoHXSxkk/3tQkYjj4lyGC8JR+LkBvqk 00LzXsmFz/38ixy8T8YnGsT7Q4/yBYL/7ESdDybLuPQRtxOS6pbqbIK43ENDRCX65j kXFpq4f3yudlea1YL9W7YU0gZ2U6eHbKtf09jvcI= Date: Tue, 29 Sep 2026 13:28:56 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,vbabka@kernel.org,usama.arif@linux.dev,surenb@google.com,shuah@kernel.org,ryan.roberts@arm.com,rppt@kernel.org,nico.pache@linux.dev,mhocko@suse.com,ljs@kernel.org,liam@infradead.org,lance.yang@linux.dev,kas@kernel.org,gourry@gourry.net,dev.jain@arm.com,david@kernel.org,baolin.wang@linux.alibaba.com,baohua@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: <20260929202857.1C5A91F00893@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: Wed, 23 Sep 2026 16:29:52 +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/20260923-fix_khugepagd_fail-v3-2-b387e92fe1a9@arm.com Signed-off-by: Yeoreum Yun Signed-off-by: Andrew Morton Reviewed-by: Baolin Wang Tested-by: Baolin Wang Reviewed-by: Gregory Price (Meta) Cc: Zi Yan Cc: Liam R. Howlett Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lance Yang Cc: Usama Arif Cc: Kiryl Shutsemau Cc: Lorenzo Stoakes Cc: Vlastimil Babka Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: David Hildenbrand Cc: Shuah Khan --- 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 (is_anon(ops)) + 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 kselftest-mm-prevent-random-failure-of-huge-page-split-for-khugepaged.patch kselftest-mm-replace-usage-of-proc-self-smaps-for-__check_pmd_huge.patch kselftest-mm-integrate-huge-page-checks.patch kselftest-mm-remove-check_huge_shmem.patch