From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1923B3B3BF1; Fri, 28 Aug 2026 08:11:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787904706; cv=none; b=C+Vtf6KdS16jPK6DMXYc7WJLoEgSQ6JxI3coNZztMOnUSaEscvpMbtofl+1utpunRbKEgP7NibL+aISeophNUWKUot0Oly59t2JYYaWUioUS9NnXouHI2HaJL+HdhB5FUmh8Rbpvkpct9o9z2zPzuvjwMODHuVP5aF/AET89OVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787904706; c=relaxed/simple; bh=USOUzZRz3c0fHctBAtbTyU36BIoeCR2Irm1oymvy1Z0=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=uI/NiwYKHVzPRjMDi7Ss8qFzVmGk5JCG/VMa/c6bkz6zQeCpx+LcOnxs+cWpeSykZDz4deZKpX/8RCH7mWUGcE6SCXV8yw6mpioiEJqf5se7tTjZMptNuBDREYaay1xYBcEHBFLM7ANQ/XcxNW+co3HEGPjCcUZUsccYC5nLeDk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=az7+7cic; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="az7+7cic" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6668D1516; Fri, 28 Aug 2026 01:11:39 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B40483F85F; Fri, 28 Aug 2026 01:11:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1787904703; bh=USOUzZRz3c0fHctBAtbTyU36BIoeCR2Irm1oymvy1Z0=; h=From:Subject:Date:To:Cc:From; b=az7+7cicnKBQ4YE1gf1xYFVll6DUXUj/0LcNUrPlF+q2kN6lMjqfpwg21E5G1r/PE Hk5FiygbfHcuyOPoOC2iqNfuaTeb2TJNTuRMsulLWoly8CUjUjJwbzN2p1m9+vlPO6 c6pNfGHqj04ZUWmk4r6hrzs10nJwXVOzZY/Tng7M= From: Yeoreum Yun Subject: [PATCH v3 0/2] kselftest: mm: fix some failure of split_huge_page_test Date: Fri, 28 Aug 2026 09:11:32 +0100 Message-Id: <20260828-fix_split-v3-0-374022586a4b@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-B4-Tracking: v=1; b=H4sIALRCkWoC/22MQQ6CMBBFr0JmbU1pqxZW3sMQU8apTCKUtIRoS O9uZe3y/f/yNkgUmRK01QaRVk4cpgL6UAEObnqS4EdhUFKdpVVSeH7f0/ziRXhjGt0QGtNbKP4 cqZx769YVHjgtIX729Fr/1n+VtRZSuN5oiSeLF/RXF8cjhhG6nPMXt8m10qAAAAA= To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Kevin Brodsky Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Yeoreum Yun X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2222; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=USOUzZRz3c0fHctBAtbTyU36BIoeCR2Irm1oymvy1Z0=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqkUK7FZ6xrgwXi+C79j9XWUXPL157DEfNDeyvK NH3vM1BzjWJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCapFCuwAKCRBt1cPRWsUx M8p4C/9JENjCUm3iTLSylTH5Q2XPNcCbR8DJj9nKskBTusG5Hj6XCUUnfr//3gO/7CasIBssnuu B5ReHNHtaHq/lbokLssbDICO5An0Q53c0pJkWddWHavvXdESeXDlqJUeVal3P19As4xwZ6zvPej iaIGGwh4QB5YrDenpijUtphEjykFlkYzIFuAMb+JtrgiWhTPAFDIG3x76EAuZrn+AdutCKtujHS xKxrfLCQk74x5IsRkOf/BQLbUa61rJmpNsN7odwpztE8dyrY1CUB0y+/XVcaAhu9iB+3ax9iX8g 1QEJ3PN/v6fXsBRQVzMR/Z8ED9czEPNzsn9nmDHMn781/Kwf/MOp2OLbsU/IGQaPTSmjZaYDCiU OvOnZOEtGwYuN9cKB3tz5pCVh+2r7qm+f0Z7Z46BOeD4mxVYeYrfeaH2MIqjTQK0FOY7KbWZWiA 2J5KY1SnR/DxPXOj3QvgCtoVO9TVWeIZb9nzhOg1Wl0Zt0ESeEMW1MwQsMRmr5BmoNa4k= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 split_huge_page_test can fail for the following reasons: 1. During the test, khugepaged may collapse previously split pages again, causing intermittent failures. 2. Since glibc commit 321e1fc73f (“malloc: Enable 2MB THP by default on AArch64”), glibc may call madvise(MADV_HUGEPAGE) for sufficiently large allocations made by memalign(). The underlying VMA may start at a different address from the aligned address returned by memalign(). Moreover, a subsequent madvise(MADV_HUGEPAGE) call does not split the VMA because it already has the same advice. This causes the test to fail because the check_huge_xxx() helpers incorrectly require the address returned by memalign() to match the VMA start address reported in /proc/self/smaps. Address these issues by applying MADV_NOHUGEPAGE after faulting in the huge page, preventing khugepaged from collapsing it again, and by replacing the use of /proc/self/smaps in the check_huge_xxx() helpers with /proc/self/pagemap and /proc/kpageflags. This patch based on mm-unstable --- Changes in v3: - change message in case of failure of madvise() with MADV_NOHUGEPAGE. - fix collapse_single_mthp (mthp_khugepaged:anon) test case failure. - Link to v2: https://lore.kernel.org/all/20260826-fix_split-v2-0-71153c7f579a@arm.com/ Changes in v2: - rebase to mm-unstable. - add message in case of failure of madvise() with MADV_NOHUGEPAGE. - fix wrong setup expected_huge in check_huge_shmem(). - Link to v1: https://lore.kernel.org/r/20260820-fix_split-v1-0-ab430c58c7cf@arm.com --- Yeoreum Yun (2): kselftest: mm: prevent random failure of huge page split for khugepaged kselftest: mm: replace usage of /proc/self/smaps for check_huge_xxx() helper tools/testing/selftests/mm/split_huge_page_test.c | 15 +++ tools/testing/selftests/mm/vm_util.c | 145 ++++++++++++++-------- tools/testing/selftests/mm/vm_util.h | 1 + 3 files changed, 107 insertions(+), 54 deletions(-) --- base-commit: 234e77148199ae43b83a0a03a3f481e03460a286 change-id: 20260820-fix_split-f44939ec44b8 Best regards, -- Sincerely, Yeoreum Yun