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=1792832261; b=1Ruds2wGrqrDpwOxWv9EDWcG6eFtBWmbvbpr3ljpZTF2YOjnfSBh+ZEb32a6Ok6Mzvis GIkbteQundeS687FlCmuE0Xh5LEvcsgIanfplwKSUjl7H/o11D569VV30uLzrhYeMbcGi PKEaPVl6gbeOvtcnAKU/daar7/mMJI05C6J+UH3qrTS0xa3Uwrn2Sz6SISNCme6PnaZwo Gk9BOi19KHOXM90MdemGcAuIEtn3PVI10aQHBu2QpPeWUPtMdcbGvB1t4gbqxUSgf1t44 ZT6ZbBObzZIj9T37wcYSGgKZwrzi/fi//yWr5t5dCQwfRYKofLKy01HRrrwGPO+2P7w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792832261; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=R5aB5wiWj1S0HP5jJyQmDI1K76Y3LBQlAGYZnNkcs/w=; b=1b4ih/bBJsKR3sm4LqWohmDt/SZcZrz4wOCdL4Z6MdbdCzmJ1vOPscXpVZQdpUVCNZcr A7HT/KprjSvRLImZ8OK5ojtFSkmpcL+oZC/aASPs5uqm2FIRF6r2tdU5QMXBYoQFiX1rq uSpTDIGGgVUp7Xcaz8xQi0B9IJmi6b8sQ8n2MEDn/bcK40x3tqPCGKeSBnlz2FqIqq1q8 xU62mdlHEIopIzPo7RoA7KViZE3P05LFCrjJm6yOV5eOiC2aTORQMY0npPAR33AmVm7Lg 1/ZoX9Bop3iZKlc6cHw9vnRd5ui1K15Jh30/jT7cj4P1tA1t5oL2rZ0TGyi+7sXxqQg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=eNzDYzx9; 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)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6E30A606A320 for ; Sat, 24 Oct 2026 08:57:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=eNzDYzx9 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 239BA1F01829; Sat, 24 Oct 2026 08:57:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1792832261; bh=R5aB5wiWj1S0HP5jJyQmDI1K76Y3LBQlAGYZnNkcs/w=; h=Date:To:From:Subject; b=eNzDYzx9n/8TuRG/ABcSBL39yE+cUMCKpZLkBMYZO0GfQlTxEShbvgPu+5/ijKiay RdsK96sqi3i81YMHxvd+bbEQSh3DaRyJ5vDf67qkXpIon5kran7RLLGV+MQhNqNk+b YwL0qaYfmu+JqeOIn5z0PG7N+zVG+CNr0r9tvvWQ= Date: Sat, 24 Oct 2026 01:57:40 -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: [merged mm-stable] kselftest-mm-fix-intermittent-failure-khugepaged-test.patch removed from -mm tree Message-Id: <20261024085741.239BA1F01829@smtp.kernel.org> X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list 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 it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Yeoreum Yun Subject: kselftest: mm: fix intermittent failure khugepaged test Date: Tue, 29 Sep 2026 11:33:19 +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/20260929-fix_khugepagd_fail-v4-2-2169c18f2576@arm.com Signed-off-by: Yeoreum Yun Signed-off-by: Andrew Morton Reviewed-by: Gregory Price (Meta) Reviewed-by: Baolin Wang Tested-by: Baolin Wang Acked-by: Lorenzo Stoakes (ARM) 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: Vlastimil Babka Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: David Hildenbrand Cc: Shuah Khan --- tools/testing/selftests/mm/khugepaged.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/tools/testing/selftests/mm/khugepaged.c~kselftest-mm-fix-intermittent-failure-khugepaged-test +++ a/tools/testing/selftests/mm/khugepaged.c @@ -618,6 +618,16 @@ static bool wait_for_scan(const char *ms usleep(TICK); } + /* + * The file and shmem tests rely on refaults to install PMD mappings + * after collapse. MADV_NOHUGEPAGE would prevent those mappings. + * + * Apply MADV_NOHUGEPAGE only to anonymous VMAs to prevent khugepaged + * from unexpectedly collapsing pages during the test. + */ + 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