From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH v3] dev: don't remove devargs that are still referenced Date: Sun, 25 Nov 2018 13:46:36 +0100 Message-ID: <3623854.KDShfdj67N@xps> References: <20181121193827.62540-1-dariusz.stojaczyk@intel.com> <20181123154328.97021-1-dariusz.stojaczyk@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev@dpdk.org, Maxime Coquelin , gaetan.rivet@6wind.com To: Darek Stojaczyk Return-path: Received: from out4-smtp.messagingengine.com (out4-smtp.messagingengine.com [66.111.4.28]) by dpdk.org (Postfix) with ESMTP id 3B46D1B453 for ; Sun, 25 Nov 2018 13:46:39 +0100 (CET) In-Reply-To: List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 23/11/2018 18:04, Maxime Coquelin: > Hi, > > On 11/23/18 4:43 PM, Darek Stojaczyk wrote: > > Even if a device failed to plug, it's still a device > > object that references the devargs. Those devargs will > > be freed automatically together with the device, but > > freeing them any earlier - like it's done in the hotplug > > error handling path right now - will give us a dangling > > pointer and a segfault scenario. > > > > Consider the following case: > > * secondary process receives the hotplug request IPC message > > * devargs are either created or updated > > * the bus is scanned > > * a new device object is created with the latest devargs > > * the device can't be plugged for whatever reason, > > bus->plug returns error > > * the devargs are freed, even though they're still referenced > > by the device object on the bus > > > > For PCI devices, the generic device name comes from > > a buffer within the devargs. Freeing those will make > > EAL segfault whenever the device name is checked. > > > > This patch just prevents the hotplug error handling > > path from removing the devargs when there's a device > > that references them. This is done by simply exiting > > early from the hotplug function. As mentioned in the > > beginning, those devargs will be freed later, together > > with the device itself. > > > > Fixes: 7e8b26650146 ("eal: fix hotplug add / remove") > > Should you also cc stable? > Above commit is in since v17.08. > > > Cc: gaetan.rivet@6wind.com > > Cc: thomas@monjalon.net > > > > Signed-off-by: Darek Stojaczyk > Acked-by: Maxime Coquelin Acked-by: Thomas Monjalon Applied (with rebase), thanks