From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4AC2C87FD1 for ; Tue, 5 Aug 2025 06:09:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2C25D8E0002; Tue, 5 Aug 2025 02:09:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 29A528E0001; Tue, 5 Aug 2025 02:09:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 188128E0002; Tue, 5 Aug 2025 02:09:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 09D108E0001 for ; Tue, 5 Aug 2025 02:09:44 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 5316C5DD98 for ; Tue, 5 Aug 2025 06:09:43 +0000 (UTC) X-FDA: 83741677446.19.9E86CDF Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by imf23.hostedemail.com (Postfix) with ESMTP id DAF5B140002 for ; Tue, 5 Aug 2025 06:09:40 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=PCyEjKdV; dmarc=pass (policy=none) header.from=ibm.com; spf=pass (imf23.hostedemail.com: domain of donettom@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=donettom@linux.ibm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1754374181; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=KZIUdYnSrH8hLHLCb8+749ChGGZ8R8KtKeM+yeFqK6M=; b=AFExFqSCmR2sIXRZwzABbT9EfZgtxuSfRQvDTprd2qt+WduvAfldHRdijzCi6jSMcNXhv7 8Gywo6NcgwHkNVFtGa6sQT2IV1juNpiIUUqAB7ix6H4Haz1PhdPam5YFgvX+GyeN9BytpS 6j0DZM29b3Cv6QaQ9qxAuRgxmNf6o78= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1754374181; a=rsa-sha256; cv=none; b=ehx2vQq/qpJ7pHhvxpfjTWmFhWDjLafFzWDZqHsChGKUCaJplyITUzWeemriNyQcpYnXpE WKTpSzBWliYiAxy0kIcd1QmfBsRVzciRzkBF1cHweskCr+RnLu6eouw/9iHFBGdJKyMmBC NDBrDMehdZkP6l6f0QAJbXB9Yq3lx+Y= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=PCyEjKdV; dmarc=pass (policy=none) header.from=ibm.com; spf=pass (imf23.hostedemail.com: domain of donettom@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=donettom@linux.ibm.com Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5754twoK000914; Tue, 5 Aug 2025 06:09:33 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=KZIUdY nSrH8hLHLCb8+749ChGGZ8R8KtKeM+yeFqK6M=; b=PCyEjKdVzoiKo7aeakZCBD dTtxSd/6ikCQAd/elqlWw/JDFE3i/qLg9FPEWM3MXUBDcLVODJ3da1DtZyNlZLCt PJg1nPYoti3+TEwYu2F2bKv6Q68DrVat19dAA5HQZTlSnKgq/CdSitHvvhsCHBS9 Rvxx26efTAqktt5ODblTPJtJs5MOFevZ55e7/t2vAf20PuoC5J6SEwPNeoN5BbJ1 SQhKtWKi4THkgIgO0tktTSRHk+C6eFARkU67zMsa349ajaZxfa1wG3GS1ICSYjMx vm0aZQkJ5c7c1dqNKaEQJFlbHtoHv28/w7vSmXFJFX7KwuKtp/h5o4pJ3RP3IQQw == Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 48bbbq07wp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 Aug 2025 06:09:32 +0000 (GMT) Received: from m0353725.ppops.net (m0353725.ppops.net [127.0.0.1]) by pps.reinject (8.18.1.12/8.18.0.8) with ESMTP id 57569WLr013800; Tue, 5 Aug 2025 06:09:32 GMT Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 48bbbq07wf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 Aug 2025 06:09:32 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 5754fB0T006873; Tue, 5 Aug 2025 06:09:31 GMT Received: from smtprelay06.dal12v.mail.ibm.com ([172.16.1.8]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 489xgmh2dy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 05 Aug 2025 06:09:31 +0000 Received: from smtpav02.wdc07v.mail.ibm.com (smtpav02.wdc07v.mail.ibm.com [10.39.53.229]) by smtprelay06.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 57569UgB22282868 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 5 Aug 2025 06:09:30 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 754B35813E; Tue, 5 Aug 2025 06:09:30 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 71EF858124; Tue, 5 Aug 2025 06:09:17 +0000 (GMT) Received: from [9.109.245.113] (unknown [9.109.245.113]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Tue, 5 Aug 2025 06:09:17 +0000 (GMT) Message-ID: <20fb853c-7d79-4d26-9c8a-f6ce9367d424@linux.ibm.com> Date: Tue, 5 Aug 2025 11:39:15 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/7] selftest/mm: Fix ksm_funtional_test failures To: Wei Yang , Aboorva Devarajan Cc: akpm@linux-foundation.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, shuah@kernel.org, pfalcato@suse.de, david@redhat.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, ritesh.list@gmail.com References: <20250729053403.1071807-1-aboorvad@linux.ibm.com> <20250729053403.1071807-4-aboorvad@linux.ibm.com> <20250804091141.ifwryfmgjepwrog4@master> Content-Language: en-US From: Donet Tom In-Reply-To: <20250804091141.ifwryfmgjepwrog4@master> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: k3p7J4adTRlrZ9ZmUW45SmpQ7mAGp2RF X-Authority-Analysis: v=2.4 cv=M65NKzws c=1 sm=1 tr=0 ts=6891a01c cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=2OwXVqhp2XgA:10 a=VnNF1IyMAAAA:8 a=0R2oKJRu712hfJE7rpUA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: aDV2fjvZ8eW6TQSfXuRrIfKTplaaXBqG X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODA1MDAzNyBTYWx0ZWRfX0Zx4ttLZjAVU MkjHC9a9E8hxGzo8KaSa/xD5kERSTjlpLOEGXz+LwvGVu9ypduqLtuTSLO5wAtsNC38EaLaoxn9 jGPGGwSl7oVPr1lriJlIVPWFmYvLpJBLDxWCZmvCLtz23b00//y4Io6jTJF1ppg5dqZj5+N7Dfe u7UxmqJBiSuLLlNTOPo4hRUdjoNwoeG4XJR1S65Oeu2sZ4ev4CCt9toK02E9/wHHAjlsSGKg1AQ 8xXnZVffvG21nJmOx68m16pKWYy6TRWsznfAN0hCSnR0KoGobD3zO42BIfPv00En1Y0cao60Ud1 qJAZNVTQ2RXAEMkfdYp5wUPjeO9qvWt9i92VEbscnusnoc/iuT9SXjP2doH/uNjQ3Rb4iA9zkQu P/zzPLVUmAwqq6Ihgj+Rl5/TdFRucHTt0z09PBgyYyqbFsMThb7ezLTeoaXpW3R5Evp6Gf/G X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-05_01,2025-08-04_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 malwarescore=0 spamscore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 clxscore=1015 mlxscore=0 phishscore=0 priorityscore=1501 mlxlogscore=999 adultscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2508050037 X-Rspamd-Queue-Id: DAF5B140002 X-Stat-Signature: m31yxzfuijec3tnj67yifi4uxhipyb7f X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1754374180-154476 X-HE-Meta: U2FsdGVkX1/c5ZdSxS1V9E61ql84ECYS6sDhcQNroRCl8eb0tDRsuSJ32BEJ/X3C3dt5VlB5n7crJuL1qDyXPD8vpOSBn/bMmTBA4KBd6hofJXhLJxhp5pnLvfCMdD3hDJPBQJbGAmiwukhz0M//3MtqQiyp3zyCdaLyHiKzyXG9iLWl1jra94DmRHNEEScT+NgaikC+Od/eWlNcOJo1oQrdt1ccr77FwharrQ/VmdlwnBUBOWwHaJsACp65AyFE1Ke+O2YYNJcVw7erXsgZDJJ9WMA7tWnHZD2AH8g1QKdQPhl39j9xE1PlIX1cdzVmOfgxbOFafShEa3UALAmKbzMG3QCTTWCnEVF7BODiuV0IPN4+/KeMvFGHO2x8KTozv5LEmAUtTaLIpOEieXsJXhpCnmRrmg5r0NZXiUXC2a8YVF1OjQOnyX0zyqNMjMVtBdmFQ0f/lF5QvKErHajfH+M16DONgp6QhLWNT0x/eMyW1GXoYQrh0mF1s0Vu0BHdGJ6MvPm8IOw6rBUNhiu+eRHkiSDM3Wt3+ywgL7Q3c1Geg5YPFMnFsKEoKwgrCQa2XPQCzzUFVnY6xXB984efWdgTlJchFaZOeNl42KNLdsuBBQtwGaDYZTCuwlZLwRIAlWblTqB0LLb3EQWdDIleKxI7qm2RhWOMGi0TFyAp34CkYnEcZHRmUQCmmhDiVh3z29HcY0kgtNdwdvVdZ7Th8ZLc8gW/PRyeKZT20z6qzhCBeAH/woMC9wKVEjGRKzX674m4lhCnDQzaURyTI9V+M8OXzqOJ0+EHvkjI95CSSVPkK5euhxwqbrcaTHQ7pC3tOcDOO42tzOIc5uIOZKRL4BRF8jwfF2qTBr+hMclgABPyj6SGVVCsymiw9bWyeRfCmtLb3BS1LaBb132C3ZCmTiI0y3fWKkkczac5+epElqVTBdkirYd1Zj650A/qauj1v4r06hvATNFBc83de+E AJWIdeAq 0XiqKkNhiZ/KxTZ4EJaHxAj6qH/15DonuumqPVDPMOSiDxk0tOHeKNGvRdE0Qhcfll57/gZIyuLKRjyVNn470TKDzg3E7DeHFFYXxLE49JlcgRs5Bh8VhVmwuAJ8bU5ir3x62IYkWsagsf3wmxZQbFvgdgvFPAXTZ7bk5f5dG0fgX4J9ADodPy6kbOPq64/Rt779i8fa/QAjs0oDQgNeC2RxNZRrI5XSrzEWQIPJvb8AqaGPnQ0VCZN5y+lqC7qnib0N7qxykODLN8PWVXEQqyl5RqJ7StQdSW0l4LyQQuQ5CEF3JEzopxT+e6o9Eb6aVoxvSZgVjo3udazx20ZOGS8ZECIB2cXiMDnlwlf87T/5tgoUA4j4YK+rCu8sNZGwu2hjx3t7K7EHBrYE= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/4/25 2:41 PM, Wei Yang wrote: > On Tue, Jul 29, 2025 at 11:03:59AM +0530, Aboorva Devarajan wrote: >> From: Donet Tom >> >> This patch fixed 2 issues. >> >> 1) After fork() in test_prctl_fork, the child process uses the file >> descriptors from the parent process to read ksm_stat and >> ksm_merging_pages. This results in incorrect values being read (parent >> process ksm_stat and ksm_merging_pages will be read in child), causing >> the test to fail. >> >> This patch calls init_global_file_handles() in the child process to >> ensure that the current process's file descriptors are used to read >> ksm_stat and ksm_merging_pages. >> >> 2) All tests currently call ksm_merge to trigger page merging. >> To ensure the system remains in a consistent state for subsequent >> tests, it is better to call ksm_unmerge during the test cleanup phase. >> >> In the test_prctl_fork test, after a fork(), reading ksm_merging_pages >> in the child process returns a non-zero value because a previous test >> performed a merge, and the child's memory state is inherited from the >> parent. >> >> Although the child process calls ksm_unmerge, the ksm_merging_pages >> counter in the parent is reset to zero, while the child's counter >> remains unchanged. This discrepancy causes the test to fail. >> >> To avoid this issue, each test should call ksm_unmerge during cleanup >> to ensure the counter is reset and the system is in a clean state for >> subsequent tests. >> >> execv argument is an array of pointers to null-terminated strings. >> In this patch we also added NULL in the execv argument. >> >> Fixes: 6c47de3be3a0 ("selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec") >> Co-developed-by: Aboorva Devarajan >> Signed-off-by: Aboorva Devarajan >> Signed-off-by: Donet Tom >> --- >> tools/testing/selftests/mm/ksm_functional_tests.c | 12 +++++++++++- >> 1 file changed, 11 insertions(+), 1 deletion(-) >> >> diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c >> index d8bd1911dfc0..996dc6645570 100644 >> --- a/tools/testing/selftests/mm/ksm_functional_tests.c >> +++ b/tools/testing/selftests/mm/ksm_functional_tests.c >> @@ -46,6 +46,8 @@ static int ksm_use_zero_pages_fd; >> static int pagemap_fd; >> static size_t pagesize; >> >> +static void init_global_file_handles(void); >> + >> static bool range_maps_duplicates(char *addr, unsigned long size) >> { >> unsigned long offs_a, offs_b, pfn_a, pfn_b; >> @@ -274,6 +276,7 @@ static void test_unmerge(void) >> ksft_test_result(!range_maps_duplicates(map, size), >> "Pages were unmerged\n"); >> unmap: >> + ksm_unmerge(); > In __mmap_and_merge_range(), we call ksm_unmerge(). Why this one not help? > > Not very familiar with ksm stuff. Would you mind giving more on how this fix > the failure you see? The issue I was facing here was test_prctl_fork was failing. # [RUN] test_prctl_fork # Still pages merged # This issue occurred because the previous test performed a merge, causing the value of /proc/self/ksm_merging_pages to reflect the number of deduplicated pages. After that, a fork() was called. Post-fork, the child process inherited the parent's ksm_merging_pages value. Then, the child process invoked __mmap_and_merge_range(), which resulted in unmerging the pages and resetting the value. However, since the parent process had performed the merge, its ksm_merging_pages value also got reset to 0. Meanwhile, the child process had not performed any merge itself, so the inherited value remained unchanged. That’s why get_my_merging_page() in the child was returning a non-zero value. Initially, I fixed the issue by calling ksm_unmerge() before the fork(), and that resolved the problem. Later, I decided it would be cleaner to move the ksm_unmerge() call to the test cleanup phase. > >> munmap(map, size); >> } >> >> @@ -338,6 +341,7 @@ static void test_unmerge_zero_pages(void) >> ksft_test_result(!range_maps_duplicates(map, size), >> "KSM zero pages were unmerged\n"); >> unmap: >> + ksm_unmerge(); >> munmap(map, size); >> } >> >> @@ -366,6 +370,7 @@ static void test_unmerge_discarded(void) >> ksft_test_result(!range_maps_duplicates(map, size), >> "Pages were unmerged\n"); >> unmap: >> + ksm_unmerge(); >> munmap(map, size); >> } >> >> @@ -452,6 +457,7 @@ static void test_unmerge_uffd_wp(void) >> close_uffd: >> close(uffd); >> unmap: >> + ksm_unmerge(); >> munmap(map, size); >> } >> #endif >> @@ -515,6 +521,7 @@ static int test_child_ksm(void) >> else if (map == MAP_MERGE_SKIP) >> return -3; >> >> + ksm_unmerge(); >> munmap(map, size); >> return 0; >> } >> @@ -548,6 +555,7 @@ static void test_prctl_fork(void) >> >> child_pid = fork(); >> if (!child_pid) { >> + init_global_file_handles(); > Would this leave fd in parent as orphan? > >> exit(test_child_ksm()); >> } else if (child_pid < 0) { >> ksft_test_result_fail("fork() failed\n"); >> @@ -595,7 +603,7 @@ static void test_prctl_fork_exec(void) >> return; >> } else if (child_pid == 0) { >> char *prg_name = "./ksm_functional_tests"; >> - char *argv_for_program[] = { prg_name, FORK_EXEC_CHILD_PRG_NAME }; >> + char *argv_for_program[] = { prg_name, FORK_EXEC_CHILD_PRG_NAME, NULL }; >> >> execv(prg_name, argv_for_program); >> return; >> @@ -644,6 +652,7 @@ static void test_prctl_unmerge(void) >> ksft_test_result(!range_maps_duplicates(map, size), >> "Pages were unmerged\n"); >> unmap: >> + ksm_unmerge(); >> munmap(map, size); >> } >> >> @@ -677,6 +686,7 @@ static void test_prot_none(void) >> ksft_test_result(!range_maps_duplicates(map, size), >> "Pages were unmerged\n"); >> unmap: >> + ksm_unmerge(); >> munmap(map, size); >> } >> >> -- >> 2.47.1 >>