From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f72.google.com (mail-pl0-f72.google.com [209.85.160.72]) by kanga.kvack.org (Postfix) with ESMTP id A80066B0546 for ; Wed, 9 May 2018 13:18:59 -0400 (EDT) Received: by mail-pl0-f72.google.com with SMTP id d9-v6so4057728plj.4 for ; Wed, 09 May 2018 10:18:59 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTPS id k22-v6si14182347pll.393.2018.05.09.10.18.58 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 May 2018 10:18:58 -0700 (PDT) Subject: [PATCH 08/13] x86/pkeys/selftests: Fix pkey exhaustion test off-by-one From: Dave Hansen Date: Wed, 09 May 2018 10:13:50 -0700 References: <20180509171336.76636D88@viggo.jf.intel.com> In-Reply-To: <20180509171336.76636D88@viggo.jf.intel.com> Message-Id: <20180509171350.E1656B95@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Dave Hansen , linuxram@us.ibm.com, tglx@linutronix.de, dave.hansen@intel.com, mpe@ellerman.id.au, mingo@kernel.org, akpm@linux-foundation.org, shuah@kernel.org From: Dave Hansen In our "exhaust all pkeys" test, we make sure that there is the expected number available. Turns out that the test did not cover the execute-only key, but discussed it anyway. It did *not* discuss the test-allocated key. Now that we have a test for the mprotect(PROT_EXEC) case, this off-by-one issue showed itself. Correct the off-by- one and add the explanation for the case we missed. Signed-off-by: Dave Hansen Cc: Ram Pai Cc: Thomas Gleixner Cc: Dave Hansen Cc: Michael Ellermen Cc: Ingo Molnar Cc: Andrew Morton Cc: Shuah Khan --- b/tools/testing/selftests/x86/protection_keys.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff -puN tools/testing/selftests/x86/protection_keys.c~pkeys-selftests-exhaust-off-by-one tools/testing/selftests/x86/protection_keys.c --- a/tools/testing/selftests/x86/protection_keys.c~pkeys-selftests-exhaust-off-by-one 2018-05-09 09:20:21.786698399 -0700 +++ b/tools/testing/selftests/x86/protection_keys.c 2018-05-09 09:20:21.790698399 -0700 @@ -1148,12 +1148,15 @@ void test_pkey_alloc_exhaust(int *ptr, u pkey_assert(i < NR_PKEYS*2); /* - * There are 16 pkeys supported in hardware. One is taken - * up for the default (0) and another can be taken up by - * an execute-only mapping. Ensure that we can allocate - * at least 14 (16-2). + * There are 16 pkeys supported in hardware. Three are + * allocated by the time we get here: + * 1. The default key (0) + * 2. One possibly consumed by an execute-only mapping. + * 3. One allocated by the test code and passed in via + * 'pkey' to this function. + * Ensure that we can allocate at least another 13 (16-3). */ - pkey_assert(i >= NR_PKEYS-2); + pkey_assert(i >= NR_PKEYS-3); for (i = 0; i < nr_allocated_pkeys; i++) { err = sys_pkey_free(allocated_pkeys[i]); _