Re: [PATCH v2 02/13] uprobes: allow ignoring of probe hits

[David Long]

On 10/19/13 13:02, Oleg Nesterov wrote:
> On 10/15, David Long wrote:
> > @@ -1732,9 +1732,6 @@ static void handle_swbp(struct pt_regs *regs)
> >   		return;
> >   	}
> >
> > -	/* change it in advance for ->handler() and restart */
> > -	instruction_pointer_set(regs, bp_vaddr);
> > -
>
> Well, this looks obviously wrong. This SET_IP() has the comment ;)
>
> Note also that with this breaks __skip_sstep() on x86.
>
> Oleg.

Yes, and there's a missing weak stub function in there too.  It was a 
surprise to me that declaring an external as weak means that it quietly 
ignores the fact there is no definition for it at link time, and makes 
it zero.  I think there may be some similar land mines elsewhere in the 
kernel, unrelated to these changes or uprobes in general.

I have an updated version to go out with the v3 patches.  It is working 
with v3.12-rc6 on x86 and ARM, to the extent I'm able to test it.

-dl

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