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

From: Steven Rostedt
Date: Wed Jun 20 2018 - 12:37:58 EST


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.

Thanks,

-- Steve