[dpdk-dev] [RFC] service: stop lcore threads before 'finalize'

[Aaron Conole]

David Marchand <david.marchand at redhat.com> writes:

> On Fri, Jan 17, 2020 at 9:17 AM David Marchand
> <david.marchand at redhat.com> wrote:
>>
>> On Thu, Jan 16, 2020 at 8:50 PM Aaron Conole <aconole at redhat.com> wrote:
>> >
>> > I've noticed an occasional segfault from the build system in the
>> > service_autotest and after talking with David (CC'd), it seems like it's
>> > due to the rte_service_finalize deleting the lcore_states object while
>> > active lcores are running.
>> >
>> > The below patch is an attempt to solve it by first reassigning all the
>> > lcores back to ROLE_RTE before releasing the memory.  There is probably
>> > a larger question for DPDK proper about actually closing the pending
>> > lcore threads, but that's a separate issue.  I've been running with the
>> > patch for a while, and haven't seen the crash anymore on my system.
>> >
>> > Thoughts?  Is it acceptable as-is?
>>
>> Added this patch to my env, still reproducing the same issue after ~10-20 tries.
>> I added a breakpoint to service_lcore_uninit that is indeed caught
>> when exiting the test application (just wanted to make sure your
>> change was in my binary).
>
> Harry,
>
> We need a fix for this issue.

+1

> Interestingly, Stephen patch that joins all pthreads at
> rte_eal_cleanup [1] makes this issue disappear.
> So my understanding is that we are missing a api (well, I could not
> find a way) to synchronously stop service lcores.

Maybe we can take that patch as a fix.  I hate to see this segfault
in the field.  I need to figure out what I missed in my cleanup
(probably missed a synchronization point).

>
> 1: https://patchwork.dpdk.org/patch/64201/