Hi Andi,

Please find the updated patch including your suggestions below.

Please let me know your comments.

Thanks
Prasanna

> +void jprobe_return(void)
> +{
> +	preempt_enable_no_resched();
> +	asm volatile ("       xchgl   %%ebx,%%esp     \n"
> +		      "       int3			\n"::"b"
> +		      (jprobe_saved_esp):"memory");
> +}
> 
> whatever the preempt disable is protecting against, why isn't it a 
> problem during the xchgl ? 
> 
> > +#define MAX_STACK_SIZE 64
> > +#define MIN_STACK_SIZE(ADDR) ((((ADDR) + MAX_STACK_SIZE) <  \
> > +	(((ADDR) & PAGE_MASK) + PAGE_SIZE) ? ((ADDR) + MAX_STACK_SIZE) \
> > +	: (((ADDR) & PAGE_MASK) + PAGE_SIZE )) - (ADDR))
> 
> What is this macro doing exactly? 
> 
> If it is an attempt to not read beyond the kernel stack top  i think
> it is wrong. It will also randomly fail on 8k stacks at top-4K 
> 
> Use something like
> 
> max_t(unsigned long,MAX_STACK_SIZE, current_thread_info() + THREAD_SIZE - addr)
> 
> 
> The rest looks ok.
> 
> -Andi
> 

-- 

Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Ph: 91-80-25044636
<prasanna@in.ibm.com>