From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Rowand Subject: Re: [PATCH] of: overlay: fix memory leak of ovcs on error exit path Date: Thu, 30 Nov 2017 08:37:09 -0500 Message-ID: <75d7d1c8-8a19-1a4c-0796-7cf69fdebe6d@gmail.com> References: <20171129191750.25254-1-colin.king@canonical.com> <806a0467-87c8-4100-c7f2-54cfa8732465@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <806a0467-87c8-4100-c7f2-54cfa8732465-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Colin Ian King , Pantelis Antoniou , Rob Herring , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: kernel-janitors-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org Hi Colin, Rob, On 11/30/17 07:18, Colin Ian King wrote: > On 30/11/17 12:14, Frank Rowand wrote: >> On 11/29/17 14:17, Colin King wrote: >>> From: Colin Ian King >>> >>> Currently if the call to of_resolve_phandles fails then then ovcs >>> is not kfree'd on the error exit path. Rather than try and make >>> the clean up exit path more convoluted, fix this by just kfree'ing >>> ovcs at the point of error detection and exit via the same exit >>> path. >>> >>> Detected by CoverityScan, CID#1462296 ("Resource Leak") >>> >>> Fixes: f948d6d8b792 ("of: overlay: avoid race condition between applying multiple overlays") >>> Signed-off-by: Colin Ian King >>> --- >>> drivers/of/overlay.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c >>> index 53bc9e3f0b98..6c8efe7d8cbb 100644 >>> --- a/drivers/of/overlay.c >>> +++ b/drivers/of/overlay.c >>> @@ -708,8 +708,10 @@ int of_overlay_apply(struct device_node *tree, int *ovcs_id) >>> of_overlay_mutex_lock(); >>> >>> ret = of_resolve_phandles(tree); >>> - if (ret) >>> + if (ret) { >>> + kfree(ovcs); >>> goto err_overlay_unlock; >>> + } >>> >>> mutex_lock(&of_mutex); >>> >>> >> >> False coverity warning. ovcs is freed in free_overlay_changeset(). >> > > The error exit path is via err_overlay_unlock: > > err_overlay_unlock: > of_overlay_mutex_unlock(); > > out: > pr_debug("%s() err=%d\n", __func__, ret); > > return ret; > > ..so there is no call to free_overlay_changeset there. > > Colin > OK, I was looking at 4.15-rc1. You must be looking at a later version where "[PATCH 1/2] of: overlay: Fix cleanup order in of_overlay_apply()" has been applied. Thanks for providing the extra details about the exit path so I could see that. Rob, I think that the fix for cleanup order was not the best way to fix that problem. A better method would have been to move "mutex_lock(&of_mutex);" up 5 lines, to just before calling of_reserve_phandles(). The problem found by coverity was caused by the "Fix cleanup order" patch. I can create that alternate fix if you would like, but I am traveling right now and don't want to submit a patch without boot testing, so there will be a slight delay. -Frank -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html