From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=ObIu=6N=vger.kernel.org=linux-kernel-owner@kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
X-Spam-Level: 
X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2
	autolearn=no autolearn_force=no version=3.4.0
Received: from mail.kernel.org (mail.kernel.org [198.145.29.99])
	by smtp.lore.kernel.org (Postfix) with ESMTP id CF2C4C83000
	for <linux-kernel@archiver.kernel.org>; Wed, 29 Apr 2020 14:32:20 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by mail.kernel.org (Postfix) with ESMTP id B2F88221EA
	for <linux-kernel@archiver.kernel.org>; Wed, 29 Apr 2020 14:32:20 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1726812AbgD2OcU (ORCPT
        <rfc822;linux-kernel@archiver.kernel.org>);
        Wed, 29 Apr 2020 10:32:20 -0400
Received: from mail.kernel.org ([198.145.29.99]:56672 "EHLO mail.kernel.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1726355AbgD2OcT (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 29 Apr 2020 10:32:19 -0400
Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225])
        (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
        (No client certificate requested)
        by mail.kernel.org (Postfix) with ESMTPSA id EA39221D82;
        Wed, 29 Apr 2020 14:32:17 +0000 (UTC)
Date:   Wed, 29 Apr 2020 10:32:16 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Joerg Roedel <jroedel@suse.de>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Shile Zhang <shile.zhang@linux.alibaba.com>,
        Andy Lutomirski <luto@amacapital.net>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Tzvetomir Stoyanov <tz.stoyanov@gmail.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [RFC][PATCH] x86/mm: Sync all vmalloc mappings before
 text_poke()
Message-ID: <20200429103216.34b6f7aa@gandalf.local.home>
In-Reply-To: <20200429141004.GR30814@suse.de>
References: <20200429054857.66e8e333@oasis.local.home>
        <20200429105941.GQ30814@suse.de>
        <20200429082854.6e1796b5@oasis.local.home>
        <20200429100731.201312a9@gandalf.local.home>
        <20200429141004.GR30814@suse.de>
X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, 29 Apr 2020 16:10:04 +0200
Joerg Roedel <jroedel@suse.de> wrote:

> On Wed, Apr 29, 2020 at 10:07:31AM -0400, Steven Rostedt wrote:
> > Talking with Mathieu about this on IRC, he pointed out that my code does
> > have a vzalloc() that is called:
> > 
> > in trace_pid_write()
> > 
> > 	pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
> > 
> > This is done when -P1,2 is on the trace-cmd command line.  
> 
> Yeah, I was guessing something like this, init_mm has a mapping which
> poking_mm has not. I currently try to reproduce this on one of my
> machines.

Note, in use_temporary_mm(poking_mm), poking_mm only contains the page that
needs to be updated. But will get added to per_cpu(cpu_tlbstate.loaded_mm),
which appears to be the one that's not updated.

-- Steve