Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758318Ab0FVOuy (ORCPT ); Tue, 22 Jun 2010 10:50:54 -0400 Received: from mail-ww0-f46.google.com ([74.125.82.46]:34698 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756022Ab0FVOuw (ORCPT ); Tue, 22 Jun 2010 10:50:52 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=kojWioCYCARFM/3KWqEVsXCZwr2XcXaqsKDN456Jxe6mnv9XZb4FCon/1cWsxzr0Ju KIfxpRRJveXJNnwP1QiuozSW1kEsrsSVeNpwRgBZOlILnbQ8QFnfMpask0DUd3dbEmyA gapTNPaSPbyBzJZRGI0KRogpchDGREYAJdmAw= Subject: Re: 2.6.34 Crash in dmaengine_put() From: Eric Dumazet To: Jeffrey Merkey Cc: Andrew Morton , linux-kernel@vger.kernel.org, Dan Williams , netdev In-Reply-To: References: <20100621202854.de928e0a.akpm@linux-foundation.org> Content-Type: text/plain; charset="UTF-8" Date: Tue, 22 Jun 2010 16:43:24 +0200 Message-ID: <1277217804.3057.428.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1668 Lines: 49 Le mardi 22 juin 2010 à 08:08 -0600, Jeffrey Merkey a écrit : Please dont top post on lkml (or netdev) messages > OK. This bug occurs if you OR in the IFF_UP flag while creating > virtual interfaces without going through the normal ifup/ifdown > scripts. Looks like a hole. I will post the trace shortly. It's > easy to reproduce, take the dummy net driver, OR in the IFF_UP flag in > dummy_setup, and watch the kernel crash. > Then dont do that ? No need to send us a trace, unless you use a pristine kernel. IFF_UP changes rules are very strict, dont try to avoid them and claim there is a hole or something wrong. Check __dev_open() , __dev_close() and __dev_change_flags() were OR/AND IFF_UP is done by core network. Net drivers are not allowed to change IFF_UP themselves. (DE-600 & DE-620 being the exceptions to confirm this rule, of course) > Jeff > > On Mon, Jun 21, 2010 at 9:28 PM, Andrew Morton > wrote: > > On Mon, 21 Jun 2010 20:57:40 -0600 Jeffrey Merkey wrote: > > > >> If someone sets the IFF_UP flags in the netdev structure without going > >> through ifup userspace stuff, during unregister of the the netdev > >> the dmaengine-put code will decrement the reference counter negative, > >> and crash at BUG! in the driver/dma/dmaengine.c code. This seems > >> busted. > >> > > > > Please send a copy of the kernel BUG trace. > > > - -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/