From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965309AbcALMcz (ORCPT ); Tue, 12 Jan 2016 07:32:55 -0500 Received: from ozlabs.org ([103.22.144.67]:45932 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753019AbcALMcx (ORCPT ); Tue, 12 Jan 2016 07:32:53 -0500 X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 35de3b1aa16842214e0cd7c6036daf4619294314 In-Reply-To: <1452483031.31943.6.camel@ellerman.id.au> To: Michael Ellerman , Steven Rostedt From: Michael Ellerman Cc: chuhu@redhat.com, linuxppc-dev@lists.ozlabs.org, LKML Subject: Re: powerpc: Implement save_stack_trace_regs() to enable kprobe stack tracing (was [RFC] ppc: Implement save_stack_trace_regs()) Message-Id: <20160112123252.1FC8B140B97@ozlabs.org> Date: Tue, 12 Jan 2016 23:32:51 +1100 (AEDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2016-11-01 at 03:30:31 UTC, Michael Ellerman wrote: > On Fri, 2016-01-08 at 17:50 -0500, Steven Rostedt wrote: > > > Are you going to take this, or do you want me to? > > Sorry, yep I'll take it. > > I trimmed the change log a bit, final version below. > > powerpc: Implement save_stack_trace_regs() to enable kprobe stack tracing > > It has come to my attention that kprobe event stack tracing does not > work on powerpc. You can see with the following: > > # cd /sys/kernel/debug/tracing > # echo stacktrace > trace_options > # echo 'p kfree' > kprobe_events > # echo 1 > events/kprobes/enable > > Will print the following warning: > save_stack_trace_regs() not implemented yet. > > Although save_stack_trace() (which normal event stack traces use) is > implemented, save_stack_trace_regs() which kprobe events use is not. > This is a cheap attempt to implement that function. > > Note, This may have issues if a task tries to get a stack trace from > another task with its regs, because it just passes in "current" to > save_context_stack(). But this does solve the issue with stack tracing > kprobe events. > > Reported-by: Chunyu Hu > Signed-off-by: Steven Rostedt > Signed-off-by: Michael Ellerman Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/35de3b1aa16842214e0cd7c603 cheers