linux-kernel - Re: [PATCH -tip] x86: Issue at least one memory barrier in stop_machine_text

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Wed, 3 Mar 2010 16:48:57 -0500
From:	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To:	Masami Hiramatsu <mhiramat@...hat.com>
Cc:	Ingo Molnar <mingo@...e.hu>, lkml <linux-kernel@...r.kernel.org>,
	systemtap <systemtap@...rces.redhat.com>,
	DLE <dle-develop@...ts.sourceforge.net>,
	Jason Baron <jbaron@...hat.com>
Subject: Re: [PATCH -tip] x86: Issue at least one memory barrier in
	stop_machine_text_poke().

* Masami Hiramatsu (mhiramat@...hat.com) wrote:
> Fix stop_machine_text_poke() to issue smp_mb() before exiting waiting
> loop, and use cpu_relax() for waiting.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>

> 
> Signed-off-by: Masami Hiramatsu <mhiramat@...hat.com>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
> Cc: Ingo Molnar <mingo@...e.hu>
> Cc: Jason Baron <jbaron@...hat.com>
> ---
> 
>  arch/x86/kernel/alternative.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index 635e4f4..3a4bf35 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -597,8 +597,8 @@ static int __kprobes stop_machine_text_poke(void *data)
>  		wrote_text = 1;
>  	} else {
>  		while (!wrote_text)
> -			smp_rmb();
> -		sync_core();
> +			cpu_relax();
> +		smp_mb();	/* Load wrote_text before following execution */
>  	}
>  
>  	flush_icache_range((unsigned long)tpp->addr,
> 
> 
> -- 
> Masami Hiramatsu
> 
> Software Engineer
> Hitachi Computer Products (America), Inc.
> Software Solutions Division
> 
> e-mail: mhiramat@...hat.com

-- 
Mathieu Desnoyers
Operating System Efficiency Consultant
EfficiOS Inc.
http://www.efficios.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/