From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: WARN_ON() hit in fsl bitbanged phy driver Date: Mon, 11 Feb 2008 16:26:01 -0600 Message-ID: <47B0CB79.7090400@freescale.com> References: <47B0C30A.1030801@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: linuxppc-dev@ozlabs.org, netdev@vger.kernel.org To: Rune Torgersen Return-path: Received: from az33egw02.freescale.net ([192.88.158.103]:44798 "EHLO az33egw02.freescale.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756936AbYBKW0K (ORCPT ); Mon, 11 Feb 2008 17:26:10 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Rune Torgersen wrote: > Scott Wood wrote: >> Rune Torgersen wrote: >>> I hit the following WARN_ON when using mii-tools agains a ethernet >>> interface using a bit-banged mii interface >> It looks like the kernel thinks it's in an interrupt, even though it >> clearly isn't from the backtrace. Presumably, something >> slept from an >> interrupt handler; try turning on sleep-in-spinlock debugging. > > I turned on sleep-in-spinlock and it did not reveal anything. I'm trying > some other debug options. > >> The root cause was probably something other than the phy code. > I'm not so sure, because it only happens when I run mii-tool agains the > interface useing the bit-banged driver, and then only the first time. OK, it seems I should have checked 2.6.24 instead of head-of-tree; softirq.c:139 is a different assertion than I thought. It's not in_irq(), but irqs_disabled(). fs_ioctl() is disabling interrupts, and spin_unlock_bh() doesn't like that. The current use of mutexes likes it even less. The locking should be moved inside the phy bus implementation, if it's needed at all. It only happens once because it's a WARN_ON_ONCE(). :-) -Scott