From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:52598) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gmDfi-0000ag-WF for qemu-devel@nongnu.org; Wed, 23 Jan 2019 03:14:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gmDfh-00084i-HO for qemu-devel@nongnu.org; Wed, 23 Jan 2019 03:14:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:61200) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gmDfh-000817-58 for qemu-devel@nongnu.org; Wed, 23 Jan 2019 03:14:05 -0500 Date: Wed, 23 Jan 2019 16:13:51 +0800 From: Peter Xu Message-ID: <20190123081351.GB18231@xz-x1> References: <20190122173111.29821-1-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190122173111.29821-1-dgilbert@redhat.com> Subject: Re: [Qemu-devel] [PATCH] migration/rdma: unegister fd handler List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert (git)" Cc: qemu-devel@nongnu.org, jemmy858585@gmail.com, quintela@redhat.com On Tue, Jan 22, 2019 at 05:31:11PM +0000, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" > > Unregister the fd handler before we destroy the channel, > otherwise we've got a race where we might land in the > fd handler just as we're closing the device. > > (The race is quite data dependent, you just have to have > the right set of devices for it to trigger). > > Corresponds to RH bz: https://bugzilla.redhat.com/show_bug.cgi?id=1666601 > > Signed-off-by: Dr. David Alan Gilbert (Could the crash happened because the same fd number is re-used after the RDMA channel was destroyed? Then when the fd has an event, it'll be delivered to rdma_cm_poll_handler() while the fd is not really the RDMA channel handle any more) Reviewed-by: Peter Xu Regards, -- Peter Xu