From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [patch 14/19] drivers/message: Move dereference after NULL test Date: Mon, 21 Dec 2009 16:27:52 -0800 Message-ID: <200912220027.nBM0Rqdo005409@imap1.linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:37299 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752736AbZLVAdf (ORCPT ); Mon, 21 Dec 2009 19:33:35 -0500 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James.Bottomley@HansenPartnership.com Cc: linux-scsi@vger.kernel.org, akpm@linux-foundation.org, julia@diku.dk, James.Bottomley@suse.de, kashyap.desai@lsi.com From: Julia Lawall If the NULL test on dev->i2o_dev or i2o_dev is needed, then the dereference should be after the NULL test. A simplified version of the semantic match that detects this problem is as follows (http://coccinelle.lip6.fr/): // @match exists@ expression x, E; identifier fld; @@ * x->fld ... when != \(x = E\|&x\) * x == NULL // Signed-off-by: Julia Lawall Cc: James Bottomley Cc: Kashyap Desai Signed-off-by: Andrew Morton --- drivers/message/i2o/i2o_block.c | 3 ++- drivers/message/i2o/i2o_scsi.c | 3 +-- 2 files changed, 3 insertions(+), 3 deletions(-) diff -puN drivers/message/i2o/i2o_block.c~drivers-message-move-dereference-after-null-test drivers/message/i2o/i2o_block.c --- a/drivers/message/i2o/i2o_block.c~drivers-message-move-dereference-after-null-test +++ a/drivers/message/i2o/i2o_block.c @@ -711,7 +711,7 @@ static int i2o_block_transfer(struct req { struct i2o_block_device *dev = req->rq_disk->private_data; struct i2o_controller *c; - u32 tid = dev->i2o_dev->lct_data.tid; + u32 tid; struct i2o_message *msg; u32 *mptr; struct i2o_block_request *ireq = req->special; @@ -727,6 +727,7 @@ static int i2o_block_transfer(struct req goto exit; } + tid = dev->i2o_dev->lct_data.tid; c = dev->i2o_dev->iop; msg = i2o_msg_get(c); diff -puN drivers/message/i2o/i2o_scsi.c~drivers-message-move-dereference-after-null-test drivers/message/i2o/i2o_scsi.c --- a/drivers/message/i2o/i2o_scsi.c~drivers-message-move-dereference-after-null-test +++ a/drivers/message/i2o/i2o_scsi.c @@ -528,7 +528,6 @@ static int i2o_scsi_queuecommand(struct * Do the incoming paperwork */ i2o_dev = SCpnt->device->hostdata; - c = i2o_dev->iop; SCpnt->scsi_done = done; @@ -538,7 +537,7 @@ static int i2o_scsi_queuecommand(struct done(SCpnt); goto exit; } - + c = i2o_dev->iop; tid = i2o_dev->lct_data.tid; osm_debug("qcmd: Tid = %03x\n", tid); _