Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756249Ab3GVEic (ORCPT ); Mon, 22 Jul 2013 00:38:32 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:51244 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756222Ab3GVEi3 (ORCPT ); Mon, 22 Jul 2013 00:38:29 -0400 From: Vaughan Cao To: joern@logfs.org Cc: dgilbert@interlog.com, JBottomley@parallels.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, vaughan.cao@oracle.com Subject: [PATCH v5 3/4] [SCSI] sg: checking sdp->detached isn't protected when open Date: Mon, 22 Jul 2013 12:40:32 +0800 Message-Id: <1374468033-8947-4-git-send-email-vaughan.cao@oracle.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1374468033-8947-1-git-send-email-vaughan.cao@oracle.com> References: <1374075246-22923-1-git-send-email-vaughan.cao@oracle.com> <1374468033-8947-1-git-send-email-vaughan.cao@oracle.com> X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2174 Lines: 70 @detached is set under the protection of sg_index_lock. Without getting the lock, new sfp will be added during sg removal and there is no chance for it to be picked out. So check with sg_index_lock held in sg_add_sfp(). Changes from v4: * use ERR_PTR series instead of adding another parameter in sg_add_sfp Signed-off-by: Vaughan Cao --- drivers/scsi/sg.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 671b760..f0e4785 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -295,21 +295,17 @@ sg_open(struct inode *inode, struct file *filp) if (flags & O_EXCL) sdp->exclude = 1; /* used by release lock */ - if (sdp->detached) { - retval = -ENODEV; - goto sem_out; - } if (sfds_list_empty(sdp)) { /* no existing opens on this device */ sdp->sgdebug = 0; q = sdp->device->request_queue; sdp->sg_tablesize = queue_max_segments(q); } - if ((sfp = sg_add_sfp(sdp, dev))) - filp->private_data = sfp; - else { - retval = -ENOMEM; + sfp = sg_add_sfp(sdp, dev); + if (IS_ERR(sfp)) { + retval = PTR_ERR(sfp); goto sem_out; } + filp->private_data = sfp; retval = 0; if (retval) { @@ -2055,7 +2051,7 @@ sg_add_sfp(Sg_device * sdp, int dev) sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN); if (!sfp) - return NULL; + return ERR_PTR(-ENOMEM); init_waitqueue_head(&sfp->read_wait); rwlock_init(&sfp->rq_list_lock); @@ -2070,6 +2066,10 @@ sg_add_sfp(Sg_device * sdp, int dev) sfp->keep_orphan = SG_DEF_KEEP_ORPHAN; sfp->parentdp = sdp; write_lock_irqsave(&sg_index_lock, iflags); + if (sdp->detached) { + write_unlock_irqrestore(&sg_index_lock, iflags); + return ERR_PTR(-ENODEV); + } list_add_tail(&sfp->sfd_siblings, &sdp->sfds); write_unlock_irqrestore(&sg_index_lock, iflags); SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp)); -- 1.7.11.7 -- 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/