linux-kernel - Re: [PATCH 2/2] tracing: syscall_regfunc() should not skip kernel threads

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

Message-ID: <5148D84A.3090604@linux.intel.com>
Date:	Tue, 19 Mar 2013 14:27:38 -0700
From:	"H. Peter Anvin" <hpa@...ux.intel.com>
To:	Steven Rostedt <rostedt@...dmis.org>
CC:	David Howells <dhowells@...hat.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Frederic Weisbecker <fweisbec@...il.com>,
	linux-kernel@...r.kernel.org,
	linux-arch <linux-arch@...r.kernel.org>
Subject: Re: [PATCH 2/2] tracing: syscall_regfunc() should not skip kernel
 threads

On 03/19/2013 08:36 AM, Steven Rostedt wrote:
> On Tue, 2013-03-19 at 15:10 +0000, David Howells wrote:
>> Steven Rostedt <rostedt@...dmis.org> wrote:
>>
>>> Why? If we remove the tracepoint from the slowpath and use a table swap,
>>> then we wouldn't need to use the slowpath at all.
>>
>> How are you engineering a table swap?  Do you patch the system call code to
>> change the immediate address loaded or do you put in a level of indirection?
> 
> Patching the call site would probably be the easiest method.
> 
> We've gotten pretty good at doing that ;-)
> 

Yes, given that the machinery is already there we might as well use it.

	-hpa


--
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/