From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.77) (envelope-from ) id 1SlB8a-0004po-Ri for garchives@archives.gentoo.org; Sun, 01 Jul 2012 03:47:53 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 0836EE07D0; Sun, 1 Jul 2012 03:47:36 +0000 (UTC) Received: from mail-qa0-f46.google.com (mail-qa0-f46.google.com [209.85.216.46]) by pigeon.gentoo.org (Postfix) with ESMTP id 3D5A1E0710 for ; Sun, 1 Jul 2012 03:46:18 +0000 (UTC) Received: by qadb17 with SMTP id b17so1361193qad.19 for ; Sat, 30 Jun 2012 20:46:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=XGrMMwjaIHK+mMNvfIdmUeDdy0i6nB2zZp32bqzNvQk=; b=MxGp/WwHUWtmPm+ch66GWeK7k/8bQeijmNsM/o1KMDVNCzlCiivobX43WO1q49Vwh2 d2xQuWtP1w6i50n9zXC+hPL6RPRMW6t6CXoiUQbmLPWn9CxkSZhWCwH6ND54cAvvawTp 57Do5gqdvbY/5BqqcJDTEPFkdaFHpQ7ihCG/cd3whGe+6v0NABts9x8fJGRbh1JkokD4 76XmZSnwEDtj8A7YmJTG4oL5OZ2cAJqdVhR3IJqlG5XOQtYCJtQSAET5yW0COgAXSQto J9Pxc2EAr0UUkgwEbHyCFtxx6FuxOSO9t5In3AjqjOAUSXl2xvRUaufThX4ilKvWhsaF 4Rcw== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.229.135.141 with SMTP id n13mr4162827qct.105.1341114378877; Sat, 30 Jun 2012 20:46:18 -0700 (PDT) Received: by 10.229.227.14 with HTTP; Sat, 30 Jun 2012 20:46:18 -0700 (PDT) In-Reply-To: References: Date: Sat, 30 Jun 2012 21:46:18 -0600 Message-ID: Subject: Re: [gentoo-user] unstoppable, undeciperable kernel call trace in log From: Maxim Wexler To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: dffed8d9-d7fe-4ffd-9bb9-455955f83d1e X-Archives-Hash: b9d5589079501ef9091ec69754cd31c5 This is weird syzygy@lumby ~ $ grep DEBUG_FS /usr/src/linux/.config # CONFIG_DEBUG_FS is not set But the entry in menuconfig ->kernel hacking looks like this:' -*- Debug Filesystem', and can't be changed. Not '[*]' which is changeable with the spacebar, but '-*-' which is not. According to it depends on TREE_RCU_TRACE=3Dy OR . But I have TREE_RCU_TRACE=3Dy. So I should be good right? But then why doesn't it select DEBUG_FS? googling lead me to http://en.wikipedia.org/wiki/Debugfs, which says do: 'mount -t debugfs none /sys/kernel/debug'. Ok, but there's no debug file or dir under /sys/kernel. Do I make one? And will it make a difference since according to grep DEBUG_FS is not set in the kernel config? I'll go and make the new kernel and see what happens. On 6/30/12, Maxim Wexler wrote: >> Hi, >> >> I don't have an answer, but if you google the phrase "rcu_bh detected >> stall on CPU" you can find many reports similar to yours and maybe >> some information. > > This might be usefu > lhttp://www.kernel.org/doc/Documentation/RCU/stallwarn.txt > > "RCU bugs can often be debugged with the help of CONFIG_RCU_TRACE" > > from in menuconfig. > > =E2=94=82 This option provides tracing in RCU which presents stats > =E2=94=82 > =E2=94=82 in debugfs for debugging RCU implementation. > > Ok, so I've set the RCU_TRACE=3Dy. Next question: How do I use debugfs, > never used it before? > >> >> Do you have RCU_CPU_STALL_INFO=3Dy in your kernel config? > > no. > > syzygy@lumby ~ $ grep RCU /usr/src/linux/.config > # RCU Subsystem > CONFIG_TREE_RCU=3Dy > # CONFIG_PREEMPT_RCU is not set > # CONFIG_RCU_TRACE is not set > CONFIG_RCU_FANOUT=3D32 > # CONFIG_RCU_FANOUT_EXACT is not set > # CONFIG_RCU_FAST_NO_HZ is not set > # CONFIG_TREE_RCU_TRACE is not set > # CONFIG_SPARSE_RCU_POINTER is not set > CONFIG_RCU_CPU_STALL_TIMEOUT=3D60 >