linux-kernel - Re: [PATCH] ftrace: Make ftrace_test

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]

Date:	Fri, 10 Oct 2008 09:12:23 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Steven Rostedt <rostedt@...dmis.org>
CC:	Ingo Molnar <mingo@...e.hu>, Anders Kaseorg <andersk@....EDU>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ftrace: Make ftrace_test_p6nop disassembler-friendly

Steven Rostedt wrote:
> On Fri, 10 Oct 2008, Ingo Molnar wrote:
> 
>> * Anders Kaseorg <andersk@....EDU> wrote:
>>
>>> Commit 4c3dc21b136f8cb4b72afee16c3ba7e961656c0b in tip introduced the
>>> 5-byte NOP ftrace_test_p6nop:
>>>   jmp . + 5
>>>   .byte 0x00, 0x00, 0x00
>>> This is not friendly to disassemblers because an odd number of 0x00s
>>> ends in the middle of an instruction boundary.  This changes the 0x00s
>>> to 1-byte NOPs (0x90).
>>>
>>> Signed-off-by: Anders Kaseorg <andersk@....edu>
>> applied to tip/tracing/ftrace, good spotting Anders!
>>
>> Steve, any objections?
> 
> Nope, it's fine with me.
> 
> Acked-by: Steven Rostedt <srostedt@...hat.com>
> 

The (semi-)amusing thing is that it should never, ever, get there.
66 66 66 66 90 is used over this, which should always work.

	-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/