From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FFD3C282CE for ; Wed, 22 May 2019 13:51:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1798F20863 for ; Wed, 22 May 2019 13:51:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="FRneyTJ1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728533AbfEVNvY (ORCPT ); Wed, 22 May 2019 09:51:24 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:40208 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726770AbfEVNvY (ORCPT ); Wed, 22 May 2019 09:51:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=7PcrUJpAN8FUR5Os5eZdN4/qfIg3FFf2/UF6cSYu22g=; b=FRneyTJ1KPX9uILNf6OYwDJke r1sUw/VWN1m3p5ISAdhvMbPPFLADQ764Wp+ofMRLOF1Ixa1dwIVr6HuEH1GwdoVNpR1adztp+plZM E5nO+VcZVOteXU3qtxUFly2BizAYJ05PghzY3RDhVnreLVIzynopkKDkQjFKDx8OYMYYkpUq+fTfC VjvPSZzzwkCVzVocdTUB7rmIgRtTiiqU/QyTwWtgpOSbpOaQY5FJB/4+D3t1nvn7jqG8kGJ6dW53O d5rXWNcHyUIkUJNOQMtQpHqRF3BK9F5pEp15zu04Mfn07X1V1MjGQYFVY14F6Zu2MJEDnGekXk3Hb L8vU2JuXA==; Received: from [31.161.185.207] (helo=worktop.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hTRe7-0001EA-LX; Wed, 22 May 2019 13:51:08 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 9FCCB984E09; Wed, 22 May 2019 15:51:06 +0200 (CEST) Date: Wed, 22 May 2019 15:51:06 +0200 From: Peter Zijlstra To: Song Liu Cc: Kairui Song , Alexei Starovoitov , lkml , Kernel Team , Josh Poimboeuf , Alexei Starovoitov , Daniel Borkmann , "bpf@vger.kernel.org" Subject: Re: Getting empty callchain from perf_callchain_kernel() Message-ID: <20190522135106.GA16275@worktop.programming.kicks-ass.net> References: <3CD3EE63-0CD2-404A-A403-E11DCF2DF8D9@fb.com> <20190517074600.GJ2623@hirez.programming.kicks-ass.net> <20190517081057.GQ2650@hirez.programming.kicks-ass.net> <20190517091044.GM2606@hirez.programming.kicks-ass.net> <8C814E68-B0B6-47E4-BDD6-917B01EC62D0@fb.com> <8449BBF3-E754-4ABC-BFEF-A8F264297F2D@fb.com> <842A0302-9B36-4FBF-ADF7-9C6749E8C5BE@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <842A0302-9B36-4FBF-ADF7-9C6749E8C5BE@fb.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, May 20, 2019 at 05:22:12PM +0000, Song Liu wrote: > I think this is still the best fix/workaround here? And only one level > of stack trace should be OK for tracepoint? No. That's still completely broken.