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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34970ECDE47 for ; Fri, 26 Oct 2018 19:57:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 054FE2082D for ; Fri, 26 Oct 2018 19:57:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 054FE2082D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727991AbeJ0Efm (ORCPT ); Sat, 27 Oct 2018 00:35:42 -0400 Received: from mga03.intel.com ([134.134.136.65]:50067 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725965AbeJ0Efl (ORCPT ); Sat, 27 Oct 2018 00:35:41 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Oct 2018 12:57:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,429,1534834800"; d="scan'208";a="103608979" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga002.jf.intel.com with ESMTP; 26 Oct 2018 12:57:21 -0700 Subject: [PATCH 2/2] x86/selftests/pkeys: fork() to check for state being preserved To: linux-kernel@vger.kernel.org Cc: Dave Hansen , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, peterz@infradead.org, mpe@ellerman.id.au, will.deacon@arm.com, luto@kernel.org, jroedel@suse.de From: Dave Hansen Date: Fri, 26 Oct 2018 12:51:47 -0700 References: <20181026195146.9C7C1136@viggo.jf.intel.com> In-Reply-To: <20181026195146.9C7C1136@viggo.jf.intel.com> Message-Id: <20181026195147.78D4C275@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen There was a bug where the per-mm pkey state was not being preserved across fork() in the child. fork() is performed in the pkey selftests, but all of our pkey activity is performed in the parent. The child does not perform any actions sensitive to pkey state. To make the test more sensitive to these kinds of bugs, add a fork() where we let the parent exit, and continue execution in the child. Signed-off-by: Dave Hansen Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: Dave Hansen Cc: Peter Zijlstra Cc: Michael Ellerman Cc: Will Deacon Cc: Andy Lutomirski Cc: Joerg Roedel --- b/tools/testing/selftests/x86/protection_keys.c | 30 ++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff -puN tools/testing/selftests/x86/protection_keys.c~x86-pkeys-no-init-at-fork-selftests tools/testing/selftests/x86/protection_keys.c --- a/tools/testing/selftests/x86/protection_keys.c~x86-pkeys-no-init-at-fork-selftests 2018-10-26 09:26:51.970102217 -0700 +++ b/tools/testing/selftests/x86/protection_keys.c 2018-10-26 09:26:51.974102217 -0700 @@ -1133,6 +1133,21 @@ void test_pkey_syscalls_bad_args(int *pt pkey_assert(err); } +void become_child(void) +{ + pid_t forkret; + + forkret = fork(); + pkey_assert(forkret >= 0); + dprintf3("[%d] fork() ret: %d\n", getpid(), forkret); + + if (!forkret) { + /* in the child */ + return; + } + exit(0); +} + /* Assumes that all pkeys other than 'pkey' are unallocated */ void test_pkey_alloc_exhaust(int *ptr, u16 pkey) { @@ -1141,7 +1156,7 @@ void test_pkey_alloc_exhaust(int *ptr, u int nr_allocated_pkeys = 0; int i; - for (i = 0; i < NR_PKEYS*2; i++) { + for (i = 0; i < NR_PKEYS*3; i++) { int new_pkey; dprintf1("%s() alloc loop: %d\n", __func__, i); new_pkey = alloc_pkey(); @@ -1152,10 +1167,17 @@ void test_pkey_alloc_exhaust(int *ptr, u if ((new_pkey == -1) && (errno == ENOSPC)) { dprintf2("%s() failed to allocate pkey after %d tries\n", __func__, nr_allocated_pkeys); - break; + } else { + pkey_assert(nr_allocated_pkeys < NR_PKEYS); + allocated_pkeys[nr_allocated_pkeys++] = new_pkey; } - pkey_assert(nr_allocated_pkeys < NR_PKEYS); - allocated_pkeys[nr_allocated_pkeys++] = new_pkey; + + /* + * Make sure that allocation state is properly + * preserved across fork(). + */ + if (i == NR_PKEYS*2) + become_child(); } dprintf3("%s()::%d\n", __func__, __LINE__); _