From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin Ian King Subject: Re: [PATCH] yam: avoid null pointer dereference error Date: Wed, 27 Mar 2013 18:08:10 +0000 Message-ID: <5153358A.5010505@canonical.com> References: <1364383174-17708-1-git-send-email-colin.king@canonical.com> <1364406257.2922.11.camel@bwh-desktop.uk.solarflarecom.com> <20130327.134651.702432728001011428.davem@davemloft.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------000203080105090700030005" Cc: bhutchings@solarflare.com, jpr@f6fbb.org, linux-hams@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: In-Reply-To: <20130327.134651.702432728001011428.davem@davemloft.net> Sender: linux-hams-owner@vger.kernel.org List-Id: netdev.vger.kernel.org This is a multi-part message in MIME format. --------------000203080105090700030005 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 27/03/13 17:46, David Miller wrote: > From: Ben Hutchings > Date: Wed, 27 Mar 2013 17:44:17 +0000 > >> On Wed, 2013-03-27 at 11:19 +0000, Colin King wrote: >>> From: Colin Ian King >>> >>> yam_open checks if dev is null, however, before that check it >>> accesses some of the fields from dev in a proceeding printk which >>> will cause a null pointer dereference error if dev is nul. Move >>> the printk to after the null check. >> >> This function will never be called with dev == NULL. > > Then let's remove at least that part of the check. > Good point. How about the following.. --------------000203080105090700030005 Content-Type: text/x-diff; name="0001-yam-remove-redundant-null-check-on-dev.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="0001-yam-remove-redundant-null-check-on-dev.patch" >>From 564f111f196d9d7293e922a68ba973210d191129 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Wed, 27 Mar 2013 13:59:05 -0400 Subject: [PATCH] yam: remove redundant null check on dev yam_open has a redundant null check on null, it will never be called with dev == NULL. Remove this redundant check. This also cleans up a smatch warning: drivers/net/hamradio/yam.c:869 yam_open() warn: variable dereferenced before check 'dev' (see line 867) Signed-off-by: Colin Ian King --- drivers/net/hamradio/yam.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/hamradio/yam.c b/drivers/net/hamradio/yam.c index 4cf8f10..b2d863f 100644 --- a/drivers/net/hamradio/yam.c +++ b/drivers/net/hamradio/yam.c @@ -866,7 +866,7 @@ static int yam_open(struct net_device *dev) printk(KERN_INFO "Trying %s at iobase 0x%lx irq %u\n", dev->name, dev->base_addr, dev->irq); - if (!dev || !yp->bitrate) + if (!yp->bitrate) return -ENXIO; if (!dev->base_addr || dev->base_addr > 0x1000 - YAM_EXTENT || dev->irq < 2 || dev->irq > 15) { -- 1.7.9.5 --------------000203080105090700030005--