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Subject: Re: [PATCH] x86, 32-bit: Fix invalid stack address while in softirq
From: Steven Rostedt <rostedt@goodmis.org>
To: Robert Richter <robert.richter@amd.com>
Cc: wyang1 <Wei.Yang@windriver.com>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org, oprofile-list@lists.sourceforge.net
Date: Thu, 06 Sep 2012 11:54:47 -0400
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On Thu, 2012-09-06 at 17:36 +0200, Robert Richter wrote:

> I meant:
> 
> unsigned long kernel_stack_pointer(struct pt_regs *regs)
> {
> 	unsigned long context = (unsigned long)regs & ~(THREAD_SIZE - 1);
> 	unsigned long sp = (unsigned long)&regs->sp;
> 	struct thread_info *tinfo;
> 
> 	if (context == (sp & ~(THREAD_SIZE - 1)))
> 		return sp;
> 	
> 	tinfo = (struct thread_info *)context;
> 	if (tinfo->previous_esp)
> 		return tinfo->previous_esp;
> 
> 	return (unsigned long)regs;
> }
> 
> -Robert
> 
> > 
> > Maybe this is even better.
> > 
> >

Yeah, this is probably the safest.

Thanks,

-- Steve