From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1L00sS-0004YU-Nt for qemu-devel@nongnu.org; Tue, 11 Nov 2008 16:34:24 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1L00sR-0004XU-1S for qemu-devel@nongnu.org; Tue, 11 Nov 2008 16:34:24 -0500 Received: from [199.232.76.173] (port=54943 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1L00sQ-0004XL-Ry for qemu-devel@nongnu.org; Tue, 11 Nov 2008 16:34:22 -0500 Received: from mx2.redhat.com ([66.187.237.31]:38152) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1L00sQ-0001wM-94 for qemu-devel@nongnu.org; Tue, 11 Nov 2008 16:34:22 -0500 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id mABLYLxY019558 for ; Tue, 11 Nov 2008 16:34:21 -0500 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id mABLYLek025022 for ; Tue, 11 Nov 2008 16:34:21 -0500 Received: from zweiblum.travel.kraxel.org (vpn-4-149.str.redhat.com [10.32.4.149]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id mABLYJ5q010066 for ; Tue, 11 Nov 2008 16:34:20 -0500 Message-ID: <4919FA5B.8090501@redhat.com> Date: Tue, 11 Nov 2008 22:34:19 +0100 From: Gerd Hoffmann MIME-Version: 1.0 Subject: Re: [Qemu-devel] [patch] Fix block I/O hang. References: <4919B46C.3040804@redhat.com> <4919B79A.5030402@codemonkey.ws> <4919C550.5020609@redhat.com> <4919C71E.2030509@codemonkey.ws> <4919F062.2070504@redhat.com> <4919F3F4.3010407@codemonkey.ws> In-Reply-To: <4919F3F4.3010407@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Anthony Liguori wrote: > Gerd Hoffmann wrote: >> >>> However, >>> >>> >>>> Third, when called from a select callback it shouldn't block >>>> indeed. It >>>> does though for me now and then when booting xen guests (with a big >>>> stack of xenner patches). Doesn't reproduce reliable though. >>>> Sprinkled >>>> in a printk (with rfd being non-blocking) and got a EAGAIN once, so it >>>> got called with rfd not having data. >>>> >>> I think it would be good to root cause this. AFAICT, it shouldn't >>> block. >>> >> >> Yes, something is fishy here. Will try to pin it. >> Ideas where to look are welcome in case you have any ;) >> > > Are you doing something funky with threads in xenner? No, I don't create any. cheers, Gerd