[dm-devel] [PATCH v3 01/19] libmultipath: fix tur checker timeout

[Martin Wilck]

On Fri, 2018-10-05 at 12:02 -0500, Benjamin Marzinski wrote:
> On Fri, Oct 05, 2018 at 12:11:18PM +0200, Martin Wilck wrote:
> > On Thu, 2018-10-04 at 11:31 -0500,  Benjamin Marzinski  wrote:
> > > 
> > > thoughts?
> > 
> > Generally speaking, we're deeply in the realm of highly unlikely
> > situations I would say. But we should get it right eventually.
> > 
> > Maybe we can add logic to the tur thread to keep its hands off the
> > context if it's a "zombie", like below (just a thought, untested)?
> 
> This still wouldn't stop a thread from racing with new thread
> creation
> to change ct->holders or ct->running.

I don't see a problem with ct->holders. Being a refcount, it seems to
be made quite for this purpose. The zombie thread _must_ decrement it
when it eventually exits. Wrt ct->running, we may have to move it under
the lock again if we want to be absolutely sure. 

Regards
Martin

-- 
Dr. Martin Wilck <mwilck at suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)