Re: perf test BPF failing on 4.15.0-rc6

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, Jan 03, 2018 at 03:33:07PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Wed, Jan 03, 2018 at 03:27:01PM -0300, Arnaldo Carvalho de Melo escreveu:
> > > Continuing investigation...
> > 
> > After applying the fallback patch to allow new tools to work with older
> > kernels:
> > 
> > [root@felicio ~]# perf test bpf
> > 39: BPF filter                                            :
> > 39.1: Basic BPF filtering                                 : Ok
> > 39.2: BPF pinning                                         : Ok
> > 39.3: BPF prologue generation                             : Ok
> > 39.4: BPF relocation checker                              : Ok
> > [root@felicio ~]# uname -a
> > Linux felicio.ghostprotocols.net 4.13.0-rc7+ #1 SMP Mon Sep 11 13:56:18 -03 2017 x86_64 x86_64 x86_64 GNU/Linux
> > [root@felicio ~]# rpm -q glibc
> > glibc-2.17-157.el7_3.2.x86_64
> > [root@felicio ~]#
> > 
> > After applying the patch below I get to, which is what I am trying to
> > fix now:
> > 
> > [root@jouet ~]# perf test bpf
> > 39: BPF filter                                            :
> > 39.1: Basic BPF filtering                                 : Ok
> > 39.2: BPF pinning                                         : Ok
> > 39.3: BPF prologue generation                             : FAILED!
> > 39.4: BPF relocation checker                              : Skip
> > [root@jouet ~]# 
> 
> Update the patch to the one at the end of this message to make it work
> with older glibcs, so that we ask for epoll_pwait() and hook into that
> as well().
> 
> Now checking why 39.3 fails...

Couldn't reproduce after fixing up some kernel build problems, the patch
below is all I need to have this working with both Fedora 27 and RHEL7,
please take a look and see if it continues to work on your systems,

- Arnaldo
 
> - Arnaldo
> 
> diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
> index 268e5f8e4aa2..d1e67e271675 100644
> --- a/tools/perf/tests/bpf-script-example.c
> +++ b/tools/perf/tests/bpf-script-example.c
> @@ -31,7 +31,7 @@ struct bpf_map_def SEC("maps") flip_table = {
>  	.max_entries = 1,
>  };
>  
> -SEC("func=SyS_epoll_wait")
> +SEC("func=SyS_epoll_pwait")
>  int bpf_func__SyS_epoll_wait(void *ctx)
>  {
>  	int ind =0;
> diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
> index 0512f1b5bfdb..7c04e2d5b60b 100644
> --- a/tools/perf/tests/bpf.c
> +++ b/tools/perf/tests/bpf.c
> @@ -25,7 +25,7 @@ static int epoll_wait_loop(void)
>  
>  	/* Should fail NR_ITERS times */
>  	for (i = 0; i < NR_ITERS; i++)
> -		epoll_wait(-(i + 1), NULL, 0, 0);
> +		epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
>  	return 0;
>  }
>