From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932303AbeCKPF2 (ORCPT ); Sun, 11 Mar 2018 11:05:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:55694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932155AbeCKPF1 (ORCPT ); Sun, 11 Mar 2018 11:05:27 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CF4FF20685 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=mhiramat@kernel.org Date: Mon, 12 Mar 2018 00:05:22 +0900 From: Masami Hiramatsu To: Ingo Molnar Cc: Thomas Gleixner , x86@kernel.org, Yang Bo , Ingo Molnar , "H . Peter Anvin" , linux-kernel@vger.kernel.org, Ananth N Mavinakayanahalli , Andrew Morton , Steven Rostedt , Laura Abbott , Josef Bacik , Alexei Starovoitov Subject: Re: [RFC PATCH -tip 8/9] error-injection: Fix to not enabling preemption in pre_handler Message-Id: <20180312000522.8bfbd3d5da5fce8a5242ee84@kernel.org> In-Reply-To: <20180310082248.6inyi5rcxhay2e6v@gmail.com> References: <152059891712.4214.9539716544254881611.stgit@devbox> <152059915597.4214.4086303893931787678.stgit@devbox> <20180310082248.6inyi5rcxhay2e6v@gmail.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 10 Mar 2018 09:22:48 +0100 Ingo Molnar wrote: > > * Masami Hiramatsu wrote: > > > Since kprobes pre_handler doesn't need to recover preemption > > even if it modifies regs->ip anymore, this fixes to remove > > the preempt_enable_no_resched() from pre_handler. > > > > Signed-off-by: Masami Hiramatsu > > --- > > kernel/fail_function.c | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/kernel/fail_function.c b/kernel/fail_function.c > > index 21b0122cb39c..b1713521f096 100644 > > --- a/kernel/fail_function.c > > +++ b/kernel/fail_function.c > > @@ -176,7 +176,6 @@ static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs) > > override_function_with_return(regs); > > /* Kprobe specific fixup */ > > reset_current_kprobe(); > > - preempt_enable_no_resched(); > > return 1; > > } > > So where did the matching preempt_disable() get removed? If it's the 6/9 patch, > then this patch (and 8/9) should very much be part of it. It is 7/9, in kprobe_int3_handler() and kprobe_ftrace_handler(). The latter is a bit tricky, originally it enable preemption only when the pre_handler returns 0, but 7/9 changes it always enables preemption. > > There should be no bisection breakage in the series. OK, I will merge 7/9-9/9 (anyway those are currently only support x86). Thanks, > > Thanks, > > Ingo -- Masami Hiramatsu