From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Mortimer Date: Thu, 17 Jan 2013 12:30:11 +0000 Subject: Re: [PATCH v2] sparc: kernel/sbus.c: fix memory leakage Message-Id: <50F7EED3.1050309@oldelvet.org.uk> List-Id: References: <1358199372-11976-1-git-send-email-dinggnu@gmail.com> <20130116211309.GA13993@merkur.ravnborg.org> <20130116211725.GC18593@gmail.com> <20130116220018.GA14063@merkur.ravnborg.org> <20130116220153.GD18593@gmail.com> <50F7D577.8010506@oldelvet.org.uk> <20130117115637.GB25615@gmail.com> In-Reply-To: <20130117115637.GB25615@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Cong Ding Cc: Sam Ravnborg , "David S. Miller" , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org On 17/01/2013 11:56, Cong Ding wrote: > On Thu, Jan 17, 2013 at 10:41:59AM +0000, Richard Mortimer wrote: >> >> >> On 16/01/2013 22:01, Cong Ding wrote: >>> the variable iommu and strbuf are not freed if it goes to error. >>> >>> Signed-off-by: Cong Ding >>> --- >>> arch/sparc/kernel/sbus.c | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/arch/sparc/kernel/sbus.c b/arch/sparc/kernel/sbus.c >>> index 1271b3a..78aa26b 100644 >>> --- a/arch/sparc/kernel/sbus.c >>> +++ b/arch/sparc/kernel/sbus.c >>> @@ -656,6 +656,8 @@ static void __init sbus_iommu_init(struct platform_device *op) >>> return; >>> >>> fatal_memory_error: >>> + kfree(strbuf); >> >> strbuf will be uninitialized if the iommu allocation fails. I don't >> have a particular preference for how to fix this but tend to dislike >> initial assignment with NULL because it hides other control flow >> issues. > Sorry I didn't notice strbuf will be uninitialized here. But if we don't > initially assign a NULL value to strbuf, I cannot find a way to handle it > besides the first version patch. Did you have any suggestions? For me, I like > the first version. Two thoughts... 1 - just use a goto target for the iommu allocation failure and make that skip the strbuf free call. The others use the existing fatal_memory_error label. 2 - Move the strbuf kzalloc up 2 lines so that it occurs before the test for iommu. 2b - In case (2) above the failure test could be changed to if (!iommu || !strbuf) to remove duplication of goto. I'd probably go for 2/2b to address Sam's initial comment. Regards Richard > - cong >> >> Regards >> >> Richard >> >>> + kfree(iommu); >>> prom_printf("sbus_iommu_init: Fatal memory allocation error.\n"); >>> } >>> >>>