Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753561AbbL2Ngq (ORCPT ); Tue, 29 Dec 2015 08:36:46 -0500 Received: from www.linutronix.de ([62.245.132.108]:42528 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753174AbbL2Ngl (ORCPT ); Tue, 29 Dec 2015 08:36:41 -0500 Date: Tue, 29 Dec 2015 14:35:35 +0100 (CET) From: Thomas Gleixner To: Steven Rostedt cc: Li Bin , mingo@redhat.com, linux-kernel@vger.kernel.org, "H. Peter Anvin" , x86@kernel.org Subject: Re: [PATCH v2 5/5] x86: ftrace: fix the comments for ftrace_modify_code_direct In-Reply-To: <20151223123725.1923be18@gandalf.local.home> Message-ID: References: <1449367378-29430-1-git-send-email-huawei.libin@huawei.com> <1449367378-29430-6-git-send-email-huawei.libin@huawei.com> <20151223123725.1923be18@gandalf.local.home> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1562 Lines: 36 On Wed, 23 Dec 2015, Steven Rostedt wrote: > On Sun, 6 Dec 2015 10:02:58 +0800 > Li Bin wrote: > > diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c > > index 311bcf3..db0f6b1 100644 > > --- a/arch/x86/kernel/ftrace.c > > +++ b/arch/x86/kernel/ftrace.c > > @@ -106,13 +106,11 @@ ftrace_modify_code_direct(unsigned long ip, unsigned const char *old_code, > > unsigned char replaced[MCOUNT_INSN_SIZE]; > > > > /* > > - * Note: Due to modules and __init, code can > > - * disappear and change, we need to protect against faulting > > - * as well as code changing. We do this by using the > > - * probe_kernel_* functions. > > - * > > - * No real locking needed, this code is run through > > - * kstop_machine, or before SMP starts. > > + * Note: > > + * We are paranoid about modifying text, as if a bug was to happen, it > > + * could cause us to read or write to someplace that could cause harm. > > + * Carefully read and modify the code with probe_kernel_*(), and make > > + * sure what we read is what we expected it to be before modifying it. > > */ > > Thomas, > > This has been now fixed. You want to ack it and I take it, or can you > take it. Or is there something else that should be fixed? Reviewed-by: Thomas Gleixner -- 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/