From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1754618AbdA0Isf (ORCPT <rfc822;w@1wt.eu>);
        Fri, 27 Jan 2017 03:48:35 -0500
Received: from mx2.suse.de ([195.135.220.15]:52408 "EHLO mx2.suse.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1754555AbdA0IrN (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 27 Jan 2017 03:47:13 -0500
Date: Fri, 27 Jan 2017 09:47:08 +0100 (CET)
From: Miroslav Benes <mbenes@suse.cz>
To: Josh Poimboeuf <jpoimboe@redhat.com>
cc: Jessica Yu <jeyu@redhat.com>, Jiri Kosina <jikos@kernel.org>,
        Petr Mladek <pmladek@suse.com>, linux-kernel@vger.kernel.org,
        live-patching@vger.kernel.org, Michael Ellerman <mpe@ellerman.id.au>,
        Heiko Carstens <heiko.carstens@de.ibm.com>, x86@kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
        Vojtech Pavlik <vojtech@suse.com>, Jiri Slaby <jslaby@suse.cz>,
        Chris J Arges <chris.j.arges@canonical.com>,
        Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
        Balbir Singh <bsingharora@gmail.com>
Subject: Re: [PATCH v4 01/15] stacktrace/x86: add function for detecting
 reliable stack traces
In-Reply-To: <dfe1419dc06f37e1f4aec5bf81d5b60e505a8d0f.1484839971.git.jpoimboe@redhat.com>
Message-ID: <alpine.LSU.2.20.1701270943420.1563@pobox.suse.cz>
References: <cover.1484839971.git.jpoimboe@redhat.com> <dfe1419dc06f37e1f4aec5bf81d5b60e505a8d0f.1484839971.git.jpoimboe@redhat.com>
User-Agent: Alpine 2.20 (LSU 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
> index 0a34489..8e8b67b 100644
> --- a/include/linux/stacktrace.h
> +++ b/include/linux/stacktrace.h
> @@ -18,6 +18,8 @@ extern void save_stack_trace_regs(struct pt_regs *regs,
>  				  struct stack_trace *trace);
>  extern void save_stack_trace_tsk(struct task_struct *tsk,
>  				struct stack_trace *trace);
> +extern int save_stack_trace_tsk_reliable(struct task_struct *tsk,
> +					 struct stack_trace *trace);
>  
>  extern void print_stack_trace(struct stack_trace *trace, int spaces);
>  extern int snprint_stack_trace(char *buf, size_t size,
> @@ -29,12 +31,12 @@ extern void save_stack_trace_user(struct stack_trace *trace);
>  # define save_stack_trace_user(trace)              do { } while (0)
>  #endif
>  
> -#else
> +#else /* !CONFIG_STACKTRACE */
>  # define save_stack_trace(trace)			do { } while (0)
>  # define save_stack_trace_tsk(tsk, trace)		do { } while (0)
>  # define save_stack_trace_user(trace)			do { } while (0)
>  # define print_stack_trace(trace, spaces)		do { } while (0)
>  # define snprint_stack_trace(buf, size, trace, spaces)	do { } while (0)

Is there a reason you did not define empty save_stack_trace_tsk_reliable() 
here? Right, it should not be needed now as livepatching is the only user, 
but still.

Miroslav