Re: [PATCH] ftrace: fix crash due to tracing of __naked functions

[Matthias Kaehlcke]

El Mon, Mar 09, 2009 at 08:46:40AM +0100 Uwe Kleine-König ha dit:

> This is a fix for the following crash observed in 2.6.29-rc3:
> http://lkml.org/lkml/2009/1/29/150
> 
> On ARM it doesn't make sense to trace a naked function because then
> mcount is called without stack and frame pointer being set up and there
> is no chance to restore the lr register to the value before mcount was
> called.
> 
> Compared to the original fix posted to arm-linux-kernel ML on 29 Jan
> 2009 by Abhishek Sagar I only changed the definition of __naked for ARM.
> 
> Reported-by: Matthias Kaehlcke <matthias@xxxxxxxxxxxx>
> Cc: Abhishek Sagar <sagar.abhishek@xxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
> Hello,
> 
> without this change a kernel having CONFIG_FUNCTION_TRACER=y doesn't
> boot on many maschines.  It would be great if this change would make it
> into .29.

i agree that it would be convenient to have this resolved in .29

Tested-by: Matthias Kaehlcke <matthias@xxxxxxxxxxxx>

-- 
Matthias Kaehlcke
Embedded Linux Engineer
Barcelona


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