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Wed, 19 Oct 2022 08:41:55 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.69]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 43E22112131B; Wed, 19 Oct 2022 08:41:52 +0000 (UTC) Date: Wed, 19 Oct 2022 09:41:49 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Bin Meng Cc: qemu-devel@nongnu.org, =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Bin Meng , Paolo Bonzini Subject: Re: [PATCH v3 1/3] util/main-loop: Fix maximum number of wait objects for win32 Message-ID: References: <20220824085231.1630804-1-bmeng.cn@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220824085231.1630804-1-bmeng.cn@gmail.com> User-Agent: Mutt/2.2.7 (2022-08-07) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.256, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Aug 24, 2022 at 04:52:29PM +0800, Bin Meng wrote: > From: Bin Meng > > The maximum number of wait objects for win32 should be > MAXIMUM_WAIT_OBJECTS, not MAXIMUM_WAIT_OBJECTS + 1. > > Signed-off-by: Bin Meng > --- > > Changes in v3: > - move the check of adding the same HANDLE twice to a separete patch > > Changes in v2: > - fix the logic in qemu_add_wait_object() to avoid adding > the same HANDLE twice > > util/main-loop.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/util/main-loop.c b/util/main-loop.c > index f00a25451b..cb018dc33c 100644 > --- a/util/main-loop.c > +++ b/util/main-loop.c > @@ -363,10 +363,10 @@ void qemu_del_polling_cb(PollingFunc *func, void *opaque) > /* Wait objects support */ > typedef struct WaitObjects { > int num; > - int revents[MAXIMUM_WAIT_OBJECTS + 1]; > - HANDLE events[MAXIMUM_WAIT_OBJECTS + 1]; > - WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1]; > - void *opaque[MAXIMUM_WAIT_OBJECTS + 1]; > + int revents[MAXIMUM_WAIT_OBJECTS]; > + HANDLE events[MAXIMUM_WAIT_OBJECTS]; > + WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS]; > + void *opaque[MAXIMUM_WAIT_OBJECTS]; > } WaitObjects; > > static WaitObjects wait_objects = {0}; > @@ -395,6 +395,9 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque) > if (w->events[i] == handle) { > found = 1; > } > + if (i == MAXIMUM_WAIT_OBJECTS - 1) { > + break; > + } Took me a while to realize this was protecting the body of the next if from out of bounds access. Can we redo this to make it explicit: > if (found) { if (found && i < (MAXIMUM_WAIT_OBJECTS - 1)) { > w->events[i] = w->events[i + 1]; > w->func[i] = w->func[i + 1]; With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|