[EXT] Re: [PATCH v3 1/4] eal: add generic support for reading PMU events

[Tomasz Duszynski]

Hello Min, 

> -----Original Message-----
> From: zhoumin <zhoumin at loongson.cn>
> Sent: Wednesday, November 30, 2022 9:33 AM
> To: Tomasz Duszynski <tduszynski at marvell.com>; dev at dpdk.org
> Cc: thomas at monjalon.net; Jerin Jacob Kollanukkaran <jerinj at marvell.com>
> Subject: [EXT] Re: [PATCH v3 1/4] eal: add generic support for reading PMU events
> 
> External Email
> 
> ----------------------------------------------------------------------
> Hi Tomasz,
> 

[...] 

> > +void
> > +eal_pmu_fini(void)
> > +{
> > +	struct rte_pmu_event *event, *tmp;
> > +	int lcore_id;
> > +
> > +	RTE_TAILQ_FOREACH_SAFE(event, &rte_pmu->event_list, next, tmp) {
> > +		TAILQ_REMOVE(&rte_pmu->event_list, event, next);
> > +		free(event->name);
> > +		rte_free(event);
> > +	}
> > +
> > +	RTE_LCORE_FOREACH_WORKER(lcore_id)
> > +		cleanup_events(lcore_id);
> > +
> > +	pmu_arch_fini();
> > +	free(rte_pmu->name);
> > +	rte_free(rte_pmu);
> > +}
> 
> There may be some problems with the implementation of eal_pmu_fini(), but I'm not sure.
> 
> I checked some test reports for this series. It seems that the test case of `debug_autotest` in
> 
> the DPDK unit test has an issue when the child process in this test case calls the function
> of  rte_exit().
> 
> The call chain is as follows:
> 
>      test_debug() -> test_exit() -> test_exit_val() -> rte_exit() ->
> rte_eal_cleanup() -> eal_pmu_fini().
> 
> The issue may be related to memory free from the error message as follows:
> 
> test_exit_valEAL: Error: Invalid memory
> EAL: Error - exiting with code: 1
>    Cause: test_exit_valEAL: Error: Invalid memory
> EAL: Error - exiting with code: 2
>    Cause: test_exit_valEAL: Error: Invalid memory
> EAL: Error - exiting with code: 255
>    Cause: test_exit_valEAL: Error: Invalid memory
> EAL: Error - exiting with code: -1
>    Cause: test_exit_valEAL: Error: Invalid memory
> 
> The above error message will disappear when I comment out the calling to the eal_pmu_fini() in
> 
> the rte_eal_cleanup().
> 

Thanks for pointing this out. This was apparently happening due to freeing same hugepage memory in forked process multiple times.