Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758800Ab1ELVld (ORCPT ); Thu, 12 May 2011 17:41:33 -0400 Received: from smtp-out.google.com ([74.125.121.67]:8232 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757968Ab1ELVlc convert rfc822-to-8bit (ORCPT ); Thu, 12 May 2011 17:41:32 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=BaUtSZV8rExLYotsySrrwwJomdfX5hqCqTGs0+4O1Mn6uIc9UUEfU0q6ZG1vG2fHLc Iywmi/3RAss8rmY9raLw== MIME-Version: 1.0 In-Reply-To: <20110512213657.GC17596@elte.hu> References: <20110512213657.GC17596@elte.hu> Date: Thu, 12 May 2011 23:41:28 +0200 Message-ID: Subject: Re: [BUG] perf: bogus correlation of kernel symbols From: Stephane Eranian To: Ingo Molnar Cc: Linus Torvalds , Arnaldo Carvalho de Melo , LKML Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1353 Lines: 37 On Thu, May 12, 2011 at 11:36 PM, Ingo Molnar wrote: > > * Stephane Eranian wrote: > >> > The bug is that perf doesn't say "I can't match kernel symbols", but >> > instead does some crazy matching and gives total crap module information (I >> > think it just picks the one that shows up last in /proc/kallsyms). >> >> But I agree perf must not silently return bogus information. It should print >> a big warning message and/or fallback to printing the raw addresses. [...] > > Yes, agreed, this is a bug in perf. I found out about this about two weeks ago > and reported it to Arnaldo, but he is away right now - he might be able to fix > it next week the earliest. > >> [...] So much for having perf in the kernel source tree to keep things in >> sync... > > What do you mean? > I meant that when this kptr feature was added, people should have scanned the entire tree (include tools/perf) to look for potential impact on programs relying on /proc/kallsyms. Having perf in the tree should have made this easier to catch. That's all. > Thanks, > >        Ingo > -- 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/