Tyrel Datwyler <tyr...@linux.vnet.ibm.com> writes: > On 09/21/2017 02:57 AM, Michael Ellerman wrote: >> Tyrel Datwyler <tyr...@linux.vnet.ibm.com> writes: >>> On 09/20/2017 04:39 AM, Michael Ellerman wrote: >>>> Rob Herring <r...@kernel.org> writes: > > <snip> > >>>> >>>> Testing a fix, will report back. >>> >>> So, that patch slipped past me. Not only is the parent reference not ours >>> to drop, but >>> when I went and looked at dlpar_cpu_add() I also noticed that of_node_put() >>> was done on >>> the parent prior to the call to dlpar_attach_node(). With the addition of >>> "parent" to the >>> dlpar_attach_node() parameter list dlpar_cpu_add() needs to be fixed up to >>> hold the >>> "parent" reference until after dlpar_attach_node() returns. >> >> Yep. I wrote the same patch :) >> >> Rob asked me to test it, which I did, but /cpus starts out with an >> elevated ref count, so you have to do ~30 (on my system) DLPAR removes >> to hit the bug, which I didn't do. > > Yeah, there are a lot of things that grab references to /cpus. So, I had a > good idea that > I needed to loop a few times adding and removing multiple cpus to trigger the > issue. Its > also obvious when using those OF trace points I wrote a while back that > refcount for /cpus > is dropping off uncharacteristically in response to symmetrical adds/removes > of cpus. I > saw your note about getting that patchset resubmitted. I'll try and get that > queued back > up soon.
Thanks, it'd be great to get it in. I applied it from the list and used it for testing this. cheers
