Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751838AbdFIOVt (ORCPT ); Fri, 9 Jun 2017 10:21:49 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:38244 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751536AbdFIOVp (ORCPT ); Fri, 9 Jun 2017 10:21:45 -0400 From: Laurent Dufour To: paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com Subject: [RFC v4 09/20] mm/spf: don't set fault entry's fields if locking failed Date: Fri, 9 Jun 2017 16:20:58 +0200 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1497018069-17790-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1497018069-17790-1-git-send-email-ldufour@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17060914-0020-0000-0000-000003845207 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17060914-0021-0000-0000-000042007C83 Message-Id: <1497018069-17790-10-git-send-email-ldufour@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-06-09_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1706090251 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1476 Lines: 50 In the case pte_map_lock failed to lock the pte or if the VMA is no more valid, the fault entry's fields should not be set so that caller won't try to unlock it. Signed-off-by: Laurent Dufour --- mm/memory.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index f05288797c60..75d24e74c4ff 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2275,6 +2275,8 @@ static bool pte_spinlock(struct vm_fault *vmf) static bool pte_map_lock(struct vm_fault *vmf) { bool ret = false; + pte_t *pte; + spinlock_t *ptl; if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) { vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, @@ -2299,18 +2301,20 @@ static bool pte_map_lock(struct vm_fault *vmf) * to invalidate TLB but this CPU has irq disabled. * Since we are in a speculative patch, accept it could fail */ - vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); - vmf->pte = pte_offset_map(vmf->pmd, vmf->address); - if (unlikely(!spin_trylock(vmf->ptl))) { - pte_unmap(vmf->pte); + ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); + pte = pte_offset_map(vmf->pmd, vmf->address); + if (unlikely(!spin_trylock(ptl))) { + pte_unmap(pte); goto out; } if (vma_has_changed(vmf->vma, vmf->sequence)) { - pte_unmap_unlock(vmf->pte, vmf->ptl); + pte_unmap_unlock(pte, ptl); goto out; } + vmf->pte = pte; + vmf->ptl = ptl; ret = true; out: local_irq_enable(); -- 2.7.4