Re: [PATCH 0/7] Uprobes: Support SDT markers having reference count (semaphore)

From: Ravi Bangoria
Date: Wed Jun 20 2018 - 22:36:02 EST




On 06/20/2018 10:07 PM, Steven Rostedt wrote:
> On Wed, 6 Jun 2018 14:03:37 +0530
> Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx> wrote:
>
>> Why RFC again:
>>
>> This series is different from earlier versions[1]. Earlier series
>> implemented this feature in trace_uprobe while this has implemented
>> the logic in core uprobe. Few reasons for this:
>> 1. One of the major reason was the deadlock between uprobe_lock and
>> mm->mmap inside trace_uprobe_mmap(). That deadlock was not easy to fix
>> because mm->mmap is not in control of trace_uprobe_mmap() and it has
>> to take uprobe_lock to loop over trace_uprobe list. More details can
>> be found at[2]. With this new approach, there are no deadlocks found
>> so far.
>> 2. Many of the core uprobe function and data-structures needs to be
>> exported to make earlier implementation simple. With this new approach,
>> reference counter logic is been implemented in core uprobe and thus
>> no need to export anything.
>
>
> A quick scan of the patches, I don't see anything controversial with
> them. Unless others have any qualms about it, I say repost as non RFC,
> and we can start doing a more thorough review.

Yes, I've posted it: https://lkml.org/lkml/2018/6/19/1324

I've copied you as well :) Please have a look.

Thanks,
Ravi