From owner-freebsd-bugs@FreeBSD.ORG Thu Aug 11 22:30:10 2005 Return-Path: X-Original-To: freebsd-bugs@hub.freebsd.org Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4472D16A420 for ; Thu, 11 Aug 2005 22:30:10 +0000 (GMT) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5717743D48 for ; Thu, 11 Aug 2005 22:30:09 +0000 (GMT) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.13.3/8.13.3) with ESMTP id j7BMU9Pi085202 for ; Thu, 11 Aug 2005 22:30:09 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.13.3/8.13.1/Submit) id j7BMU9TM085201; Thu, 11 Aug 2005 22:30:09 GMT (envelope-from gnats) Resent-Date: Thu, 11 Aug 2005 22:30:09 GMT Resent-Message-Id: <200508112230.j7BMU9TM085201@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Rudolf Cejka Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6107316A41F for ; Thu, 11 Aug 2005 22:27:34 +0000 (GMT) (envelope-from cejkar@fit.vutbr.cz) Received: from kazi.fit.vutbr.cz (kazi.fit.vutbr.cz [147.229.8.12]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2FF7B43D5A for ; Thu, 11 Aug 2005 22:27:32 +0000 (GMT) (envelope-from cejkar@fit.vutbr.cz) Received: from kazi.fit.vutbr.cz (localhost [127.0.0.1]) by kazi.fit.vutbr.cz (envelope-from cejkar@fit.vutbr.cz) (8.13.4/8.13.4) with ESMTP id j7BMRU1Z011907 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 12 Aug 2005 00:27:30 +0200 (CEST) Received: (from cejkar@localhost) by kazi.fit.vutbr.cz (8.13.4/8.13.1/Submit) id j7BMRUPe011906; Fri, 12 Aug 2005 00:27:30 +0200 (CEST) (envelope-from cejkar) Message-Id: <200508112227.j7BMRUPe011906@kazi.fit.vutbr.cz> Date: Fri, 12 Aug 2005 00:27:30 +0200 (CEST) From: Rudolf Cejka To: FreeBSD-gnats-submit@FreeBSD.org X-Send-Pr-Version: 3.113 Cc: Subject: kern/84823: [PATCH] bpf in non-blocking mode is broken X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Rudolf Cejka List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Aug 2005 22:30:10 -0000 >Number: 84823 >Category: kern >Synopsis: [PATCH] bpf in non-blocking mode is broken >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Aug 11 22:30:08 GMT 2005 >Closed-Date: >Last-Modified: >Originator: Rudolf Cejka >Release: FreeBSD 5.3-STABLE i386 >Organization: FIT, Brno University of Technology, Czech Republic >Environment: Any FreeBSD since Dec 17 2000 with sys/net/bpf.c >= 1.72. >Description: When bpf is in non-blocking mode, it always returns EWOULDBLOCK - it never returns any data. The bpf is broken since following commit: : Revision 1.72, Sun Dec 17 20:50:22 2000 UTC (4 years, 7 months ago) : : Fix bug: a read() on a bpf device which was in non-blocking mode : and had no data available returned 0. Now it returns -1 with errno : set to EWOULDBLOCK (== EAGAIN) as it should. This fix makes the bpf : device usable in threaded programs. >How-To-Repeat: >Fix: Following patch should fix the problem: --- sys/net/bpf.c.orig Thu Aug 11 23:24:42 2005 +++ sys/net/bpf.c Thu Aug 11 23:27:10 2005 @@ -489,8 +489,13 @@ } if (ioflag & O_NONBLOCK) { - BPFD_UNLOCK(d); - return (EWOULDBLOCK); + if (d->bd_slen == 0) { + BPFD_UNLOCK(d); + return (EWOULDBLOCK); + } else { + ROTATE_BUFFERS(d); + break; + } } error = msleep(d, &d->bd_mtx, PRINET|PCATCH, "bpf", d->bd_rtout); >Release-Note: >Audit-Trail: >Unformatted: