lkml.org 
[lkml]   [2013]   [Oct]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 02/13] uprobes: allow ignoring of probe hits
Sorry for the delay, all this week it's me that's traveling.


On 10/28/13 14:54, Oleg Nesterov wrote:
> David, sorry for delay.
>
> On 10/19, 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.
>
> Hmm. Thinking more, it seems that this patch has another problem.
>
> IIUC, the whole point of arch_uprobe_ignore() is to avoid
> handler_chain() if the condition was not satisfied, so you need
> to call it before handler_chain() ?

Yes, you're right. I can see now that is a bad merge of an earlier
version of the patch. I have just tested the fix. Thanks for finding this.

>
> Otherwise this logic should go into can_skip_sstep() and we simply
> do not need the new hook, just we need to tweak the (ugly)
> UPROBE_SKIP_SSTEP logic.
>
> Oleg.
>


-dl



\
 
 \ /
  Last update: 2013-10-30 22:21    [W:0.213 / U:0.688 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site