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b=VkHIdnuqbLB+mjbkjrPTaSTMAZDlBdV8QV5FamIkRBGy5iTcGOjTs6O+y5OxQne4v dFr/obRcQ3BwaD8droZfw9DOzQUXclknXRiRFod0uOAlam2QhHqZw4QK5s/2DiyA+M 4V5MEJOh7e7MJXYxNQkxgVCRAUX+tA4a3EXdluuo= Date: Sat, 10 Jan 2026 16:37:04 -0800 From: Andrew Morton To: Sun Jian Cc: Shuah Khan , linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park Subject: Re: [PATCH] selftests/mm: ksm_tests: skip when not run as root Message-Id: <20260110163704.7b5e1e10735113baa23f42ef@linux-foundation.org> In-Reply-To: <20260109094313.52307-1-sun.jian.kdev@gmail.com> References: <20260109094313.52307-1-sun.jian.kdev@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: 7utoj7poqe7xkkswa54djgj9ndjdahi7 X-Rspamd-Queue-Id: A6983180004 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1768091826-27730 X-HE-Meta: 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 sQwYmwqP mNw6WgcpUr/CSrwIRLGuHyOfmcxVj1d9iBVqhLgHcCu+JqIMMaheyKDAGQw4Go5r15lTW1FtiyLvzxz08x8GOr8x1K7DeNIhG8sH1E/ARG9iRRmHQ0mTXrejdFx+jRbAAoWX4E1gTHwZYdl2AYDil+kT5TUWABm9AIOM5yiLuvX8MFByqNuXj1HkBd/F07WPNkL+O41nMJzZXh/1CndDEetV4tkZLDoVmSxfn5vc5uE05mYpuFgPJWD7rej5VJ09jpfGgvKWU0wiw6UdkzJoLkknsB+2LMMB0WOCbtcRWd28rulukxApifdf212zuQGsoZ66hJHY/sMzdWj57kC7UPwN5ItBi5Ik8WViN 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 Fri, 9 Jan 2026 17:43:13 +0800 Sun Jian wrote: > ksm_tests writes KSM sysfs knobs under /sys/kernel/mm/ksm, which requires > root privileges. When run unprivileged, it fails with permission errors > and reports FAIL, which is misleading. > > Skip the test early when not run as root to avoid false failures. Thanks. When reissuing a patch it's nice to cc those individuals who commented on previous versions. > --- a/tools/testing/selftests/mm/ksm_tests.c > +++ b/tools/testing/selftests/mm/ksm_tests.c > @@ -766,6 +766,11 @@ int main(int argc, char *argv[]) > bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT; > long size_MB = 0; > > + if (geteuid() != 0) { > + printf("# SKIP ksm_tests requires root privileges\n"); > + return KSFT_SKIP; > + } > + lgtm. selftests/ code performs this test in about 20 places already, all different. In the interests of consistency and code cleanliness, perhaps some kind person will centralize this check in some fashion!