Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755329AbbESHVJ (ORCPT ); Tue, 19 May 2015 03:21:09 -0400 Received: from terminus.zytor.com ([198.137.202.10]:60406 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755253AbbESHVC (ORCPT ); Tue, 19 May 2015 03:21:02 -0400 Date: Tue, 19 May 2015 00:20:26 -0700 From: tip-bot for David Hildenbrand Message-ID: Cc: dahi@linux.vnet.ibm.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, linux-kernel@vger.kernel.org, hpa@zytor.com, tglx@linutronix.de Reply-To: torvalds@linux-foundation.org, mingo@kernel.org, dahi@linux.vnet.ibm.com, tglx@linutronix.de, hpa@zytor.com, peterz@infradead.org, linux-kernel@vger.kernel.org In-Reply-To: <1431359540-32227-9-git-send-email-dahi@linux.vnet.ibm.com> References: <1431359540-32227-9-git-send-email-dahi@linux.vnet.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/preempt, futex: Disable preemption in UP futex_atomic_op_inuser() explicitly Git-Commit-ID: f3dae07e442a8131a5485b6a38db2aa22a7a48cf X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2725 Lines: 79 Commit-ID: f3dae07e442a8131a5485b6a38db2aa22a7a48cf Gitweb: http://git.kernel.org/tip/f3dae07e442a8131a5485b6a38db2aa22a7a48cf Author: David Hildenbrand AuthorDate: Mon, 11 May 2015 17:52:13 +0200 Committer: Ingo Molnar CommitDate: Tue, 19 May 2015 08:39:16 +0200 sched/preempt, futex: Disable preemption in UP futex_atomic_op_inuser() explicitly Let's explicitly disable/enable preemption in the !CONFIG_SMP version of futex_atomic_op_inuser, to prepare for pagefault_disable() not touching preemption anymore. Otherwise we might break mutual exclusion when relying on a get_user()/ put_user() implementation. Reviewed-and-tested-by: Thomas Gleixner Signed-off-by: David Hildenbrand Signed-off-by: Peter Zijlstra (Intel) Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-9-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- include/asm-generic/futex.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h index b59b5a5..3586017 100644 --- a/include/asm-generic/futex.h +++ b/include/asm-generic/futex.h @@ -8,8 +8,7 @@ #ifndef CONFIG_SMP /* * The following implementation only for uniprocessor machines. - * For UP, it's relies on the fact that pagefault_disable() also disables - * preemption to ensure mutual exclusion. + * It relies on preempt_disable() ensuring mutual exclusion. * */ @@ -38,6 +37,7 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; + preempt_disable(); pagefault_disable(); ret = -EFAULT; @@ -72,6 +72,7 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) out_pagefault_enable: pagefault_enable(); + preempt_enable(); if (ret == 0) { switch (cmp) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/