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From: Zachary Amsden <zach@vmware.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>,
	virtualization@lists.osdl.org, Andrew Morton <akpm@osdl.org>,
	Chris Wright <chrisw@osdl.org>,
	Linus Torvalds <torvalds@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	Martin Bligh <mbligh@mbligh.org>,
	Pratap Subrahmanyam <pratap@vmware.com>,
	Christopher Li <chrisl@vmware.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	prasanna@in.ibm.com, ananth@in.ibm.com,
	anil.s.keshavamurthy@intel.com, davem@davemloft.net
Subject: Re: [PATCH 19/21] i386 Kprobes semaphore fix
Date: Wed, 09 Nov 2005 09:52:40 -0800	[thread overview]
Message-ID: <43723768.2060103@vmware.com> (raw)
In-Reply-To: <20051109165804.GA15481@elte.hu>

Ingo Molnar wrote:

>* Zachary Amsden <zach@vmware.com> wrote:
>
>  
>
>>>I believe user space kprobes are being worked on by some IBM India folks 
>>>yes.
>>>      
>>>
>>I'm convinced this is pointless.  What does it buy you over a ptrace 
>>based debugger?  Why would you want extra code running in the kernel 
>>that can be done perfectly well in userspace?
>>    
>>
>
>kprobes are not just for 'debuggers', they are also used for tracing and 
>other dynamic instrumentation in projects like systemtap. Ptrace is way 
>too slow and limited for things like that.
>  
>

Well, if there is a justification for it, that means we really should 
handle all the nasty EIP conversion cases due to segmentation and v8086 
mode in the kprobes code.  I was hoping that might not be the case.

Zach

  reply	other threads:[~2005-11-09 17:55 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-08  4:39 [PATCH 19/21] i386 Kprobes semaphore fix Zachary Amsden
2005-11-08 13:12 ` Andi Kleen
2005-11-08 13:36   ` Zachary Amsden
2005-11-09 13:38     ` Andi Kleen
2005-11-09 16:46       ` Zachary Amsden
2005-11-09 16:58         ` Ingo Molnar
2005-11-09 17:52           ` Zachary Amsden [this message]
2005-11-10 18:09             ` Prasanna S Panchamukhi
2005-11-10 14:58               ` Zachary Amsden
2005-11-10 16:16               ` H. Peter Anvin
2005-11-11 15:27             ` Andi Kleen
2005-11-11 15:25         ` Andi Kleen
2005-11-14  5:54           ` Prasanna S Panchamukhi
     [not found]     ` <20051109093755.GA10361@in.ibm.com>
2005-11-10 16:33       ` Prasanna S Panchamukhi
     [not found] <20051108074430.GG28201@elte.hu>
2005-11-08 13:26 ` Zachary Amsden

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