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From: Catalin Marinas <catalin.marinas@arm.com>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: venki kaps <venkiece2005@gmail.com>, Nicolas Pitre <nico@cam.org>,
	"sagar.abhishek@gmail.com" <sagar.abhishek@gmail.com>,
	"jkenisto@us.ibm.com" <jkenisto@us.ibm.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"prasanna@in.ibm.com" <prasanna@in.ibm.com>
Subject: Re: ARM + jprobes/kretprobes SEGV/hangs/OOPS in 2.6.29 kernel
Date: Tue, 01 Sep 2009 15:43:59 +0100	[thread overview]
Message-ID: <1251816239.10349.66.camel@pc1117.cambridge.arm.com> (raw)
In-Reply-To: <20090901142549.GA21501@flint.arm.linux.org.uk>

On Tue, 2009-09-01 at 15:25 +0100, Russell King wrote:
> On Tue, Sep 01, 2009 at 02:54:54PM +0100, Catalin Marinas wrote:
> > venki kaps <venkiece2005@gmail.com> wrote:
> > > I have found the exact problem with respect to ARM jprobes.
> > >
> > > The problem with configure i.e, CONFIG_ARM_UNWIND = y; is enabled.
> > 
> > I haven't followed the kprobes implementation for ARM but does it make
> > any assumptions about the existence of a frame pointer on the stack?
> > Enabling stack unwinding automatically disables the framepointer.
> 
> If it uses CALLER_ADDRESSx() then it won't work with unwinding enabled.
> See 5613/1 (which is pending in the devel branch.)

In addition to that, when CONFIG_FRAME_POINTER is disabled, the lr
register isn't always saved on the stack by the called function. I'm not
sure whether kretprobe_trampoline is aware of this.

-- 
Catalin


  reply	other threads:[~2009-09-01 14:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-25 10:42 venki kaps
2009-08-25 17:37 ` Nicolas Pitre
2009-08-31  5:27   ` venki kaps
2009-08-31 10:11     ` venki kaps
2009-09-01  6:55       ` venki kaps
2009-09-01 13:54         ` Catalin Marinas
2009-09-01 14:25           ` Russell King
2009-09-01 14:43             ` Catalin Marinas [this message]
2009-09-01 17:56               ` Nicolas Pitre
2009-09-16  9:40                 ` venki kaps

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