Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751360AbaK0RK3 (ORCPT ); Thu, 27 Nov 2014 12:10:29 -0500 Received: from e06smtp11.uk.ibm.com ([195.75.94.107]:59785 "EHLO e06smtp11.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750861AbaK0RK2 (ORCPT ); Thu, 27 Nov 2014 12:10:28 -0500 From: David Hildenbrand To: linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Cc: benh@kernel.crashing.org, paulus@samba.org, akpm@linux-foundation.org, heiko.carstens@de.ibm.com, dahi@linux.vnet.ibm.com, schwidefsky@de.ibm.com, borntraeger@de.ibm.com, mst@redhat.com, tglx@linutronix.de, David.Laight@ACULAB.COM Subject: [PATCH RFC 0/2] Reenable might_sleep() checks for might_fault() when atomic Date: Thu, 27 Nov 2014 18:10:15 +0100 Message-Id: <1417108217-42687-1-git-send-email-dahi@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.5.5 In-Reply-To: <1416915806-24757-1-git-send-email-dahi@linux.vnet.ibm.com> References: <1416915806-24757-1-git-send-email-dahi@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14112717-0005-0000-0000-00000240EBE1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Simple prototype to enable might_sleep() checks in might_fault(), avoiding false positives for scenarios involving explicit pagefault_disable(). So this should work: spin_lock(&lock); /* also if left away */ pagefault_disable() rc = copy_to_user(...) pagefault_enable(); spin_unlock(&lock); /* And this should report a warning again: spin_lock(&lock); rc = copy_to_user(...); spin_unlock(&lock); Still missing: - Split of preempt documentation update + preempt_active define reshuffle - Debug version to test for over/underflows - Change documentation of user access methods to reflect the real behavior - Don't touch the preempt counter, only the pagefault disable counter (future work) David Hildenbrand (2): preempt: track pagefault_disable() calls in the preempt counter mm, sched: trigger might_sleep() in might_fault() when pagefaults are disabled include/linux/kernel.h | 9 +++++++-- include/linux/preempt_mask.h | 24 +++++++++++++++++++----- include/linux/uaccess.h | 21 ++++++++++++++------- mm/memory.c | 15 ++++----------- 4 files changed, 44 insertions(+), 25 deletions(-) -- 1.8.5.5 -- 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/