From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 802C5388E78; Thu, 2 Apr 2026 07:28:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775114904; cv=none; b=ZATgEftmuQj+xv4Ewk9MGZ51mmdnu+9IIwvW24ig2rbJLwRQkUniekUUN9mzi+feFMh2HcAxjrm6uuz0clcL4OCljsfmGzcw2c1f4d7WJd6w+mjRzLj5Msr1tQ+uk3qu9d+sgO5mba2zmzbkYdeazt7f7cPPb9oLh4prkT8zm5w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775114904; c=relaxed/simple; bh=s4DktcxYHxIQyKItWyyiTcktdapW1VOpPYdWxcQrfYI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hvVtppD7RnZYZBKsdk0A1+/qew9mipA25taWau7SGTbRhsyMPWO+CBuTKfZX2LUT48tTr0D3ONTlgf+LqDiqYodhGi/Qc/JyXzvY00I2A3+N6o3E4UCPIS+Fd0oN3RB9QD45rEhc1ZTxqOtol8WgsW4P9j0WmdRb9sKqvuFmoo4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jSSyx/XU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jSSyx/XU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4D20C2BC9E; Thu, 2 Apr 2026 07:28:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775114904; bh=s4DktcxYHxIQyKItWyyiTcktdapW1VOpPYdWxcQrfYI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=jSSyx/XUgzH8me+WQNiUcNtdsh5wE7pEg1D5p26XknqUIoOrz4umY52V9T8+OJeCp wBxHXhPy8IJfp0NTA4PR30iX8xEPBq50qJc3ZsxwvcBFcm3eK98t1w4myGez8zT4FJ mRfZm5qMFTBCuvU0gX72h4+ZnK1KHmFTfs4uRIibTh+5Qrzop4y7CdZD+CPCSwRW5o eUPrV1nH0YqEI0BDVlqvpu8CYpq2fdZWPl3s6l7FUdg4cv5Uj6oH9UW4+PRDTu6V0x 5ZeESauDqpj+ms090X7/idd+ykAN1fFvaQoVkAmwkhmCdW510uXxG/sU+iwe5tw1SJ 19b3qLLVde9JQ== Message-ID: <4f6d4ee8-9f2b-4da8-9456-f47cccfe4367@kernel.org> Date: Thu, 2 Apr 2026 09:28:16 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] selftests/mm: verify droppable mappings cannot be locked To: Anthony Yznaga , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: akpm@linux-foundation.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, jannh@google.com, pfalcato@suse.de, Jason@zx2c4.com, shuah@kernel.org References: <20260402003417.438037-1-anthony.yznaga@oracle.com> <20260402003417.438037-3-anthony.yznaga@oracle.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit > + > +/* > + * Droppable memory should not be lockable. > + */ > +static void test_mlock_droppable(void) > +{ > + char *map; > + unsigned long page_size = getpagesize(); > + > + /* > + * Ensure MCL_FUTURE is not set. > + */ > + if (mlockall(MCL_CURRENT)) > + ksft_exit_fail_msg("mlockall(MCL_CURRENT): %s\n", strerror(errno)); Why do we need the prior mlockall()? If that is really required, the comment should be clearer why the munlockall() is insufficient. Also, why can't we fail only the test? > + if (munlockall()) > + ksft_exit_fail_msg("munlockall() %s\n", strerror(errno)); Why can't we fail only the test? > + > + map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE, > + MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0); > + if (map == MAP_FAILED) { > + if (errno == EOPNOTSUPP) { > + ksft_test_result_skip("%s: MAP_DROPPABLE not supported\n", __func__); > + return; > + } > + ksft_exit_fail_msg("mmap error: %s\n", strerror(errno)); same. > + } > + > + if (mlock2_(map, 2 * page_size, 0)) { > + munmap(map, 2 * page_size); Not required when exiting either way? > + ksft_exit_fail_msg("mlock2(0): %s\n", strerror(errno)); > + } > + > + ksft_test_result(!unlock_lock_check(map, false), "%s: droppable memory not locked\n", > + __func__); > + > + munmap(map, 2 * page_size); > +} > + > +static void test_mlockall_future_droppable(void) > +{ > + char *map; > + unsigned long page_size = getpagesize(); > + > + if (mlockall(MCL_CURRENT | MCL_FUTURE)) > + ksft_exit_fail_msg("mlockall(MCL_CURRENT | MCL_FUTURE): %s\n", strerror(errno)); Similar comments as for the other path regarding ksft_exit_fail_msg() etc. > + > + map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE, > + MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0); > + > + if (map == MAP_FAILED) { > + if (errno == EOPNOTSUPP) { > + ksft_test_result_skip("%s: MAP_DROPPABLE not supported\n", __func__); > + return; > + } > + ksft_exit_fail_msg("mmap error: %s\n", strerror(errno)); > + } > + > + ksft_test_result(!unlock_lock_check(map, false), "%s: droppable memory not locked\n", > + __func__); > + > + if (munlockall()) { > + munmap(map, 2 * page_size); > + ksft_exit_fail_msg("munlockall() %s\n", strerror(errno)); > + } > + > munmap(map, 2 * page_size); > } -- Cheers, David