Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932357Ab0HaO6q (ORCPT ); Tue, 31 Aug 2010 10:58:46 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:45515 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932281Ab0HaO6p (ORCPT ); Tue, 31 Aug 2010 10:58:45 -0400 X-Authority-Analysis: v=1.1 cv=PwepQEbt00S2KBGxbslVOIF+r0Mv8f+EI4NDy2BEsUE= c=1 sm=0 a=fCqi14YzsQAA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=hGzw-44bAAAA:8 a=kjFs-KGKNYa_KYX7xukA:9 a=rt0vMKGqOxe9pG7VLQwA:7 a=CbKKcx_fiPoCCD1Av-9uAjzCqwIA:4 a=PUjeQqilurYA:10 a=dowx1zmaLagA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [PATCH] tracing/trace_stack: Fix stack trace on ppc64 From: Steven Rostedt To: Frederic Weisbecker Cc: Anton Blanchard , mingo@redhat.com, linux-kernel@vger.kernel.org In-Reply-To: <20100831142111.GA5259@nowhere> References: <20100825013238.GE28360@kryten> <1283218310.1377.50.camel@gandalf.stny.rr.com> <20100831142111.GA5259@nowhere> Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 31 Aug 2010 10:58:42 -0400 Message-ID: <1283266722.1377.80.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2369 Lines: 58 On Tue, 2010-08-31 at 16:21 +0200, Frederic Weisbecker wrote: > On Mon, Aug 30, 2010 at 09:31:50PM -0400, Steven Rostedt wrote: > > On Wed, 2010-08-25 at 11:32 +1000, Anton Blanchard wrote: > > > save_stack_trace() stores the instruction pointer, not the function > > > descriptor. On ppc64 the trace stack code currently dereferences the > > > instruction pointer and shows 8 bytes of instructions in our backtraces: > > > > > > # cat /sys/kernel/debug/tracing/stack_trace > > > Depth Size Location (26 entries) > > > ----- ---- -------- > > > 0) 5424 112 0x6000000048000004 > > > 1) 5312 160 0x60000000ebad01b0 > > > 2) 5152 160 0x2c23000041c20030 > > > 3) 4992 240 0x600000007c781b79 > > > 4) 4752 160 0xe84100284800000c > > > 5) 4592 192 0x600000002fa30000 > > > 6) 4400 256 0x7f1800347b7407e0 > > > 7) 4144 208 0xe89f0108f87f0070 > > > 8) 3936 272 0xe84100282fa30000 > > > > > > Since we aren't dealing with function descriptors, use %pS instead of %pF > > > to fix it: > > > > > > # cat /sys/kernel/debug/tracing/stack_trace > > > Depth Size Location (26 entries) > > > ----- ---- -------- > > > 0) 5424 112 ftrace_call+0x4/0x8 > > > 1) 5312 160 .current_io_context+0x28/0x74 > > > 2) 5152 160 .get_io_context+0x48/0xa0 > > > 3) 4992 240 .cfq_set_request+0x94/0x4c4 > > > 4) 4752 160 .elv_set_request+0x60/0x84 > > > 5) 4592 192 .get_request+0x2d4/0x468 > > > 6) 4400 256 .get_request_wait+0x7c/0x258 > > > 7) 4144 208 .__make_request+0x49c/0x610 > > > 8) 3936 272 .generic_make_request+0x390/0x434 > > > > > > Signed-off-by: Anton Blanchard > > > > Thanks, I'll test this to make sure it doesn't break x86, and then push > > it into a stable/-rc patch queue. > > > > -- Steve > > > Ingo has applied it already in perf/urgent. Hmm, I never saw the tip-bot reply :-( I guess it only sends to the Cc tags. -- Steve -- 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/