[LTP] question about the EPERM error of LTP bpf test

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> 
> 
> ----- Original Message -----
> > 
> > on 2019/11/04 18:50, Jan Stancek wrote:
> > 
> > >
> > > ----- Original Message -----
> > >> Hi All
> > >>
> > >> Now, I test bpf_prog02 and bpf_prog03 in my
> > >> system(4.18.0-107.el8.x86_64).
> > >>
> > >> #./bpf_prog03
> > >> tst_buffers.c:55: INFO: Test is using guarded buffers
> > >> tst_test.c:1137: INFO: Timeout per run is 0h 05m 00s
> > >> bpf_common.h:18: INFO: Raising RLIMIT_MEMLOCK to 262143
> > >> tst_capability.c:29: INFO: Dropping CAP_SYS_ADMIN(21)
> > >> bpf_common.h:37: CONF: bpf() requires CAP_SYS_ADMIN on this system:
> > >> EPERM
> > >> (1)
> > >> #
> > >>
> > >> Jan Stancek has added rlimit_bump_memlock function to avoid EPERM errno,
> > >> but I still can meet this problem every time even though I have
> > >> increased
> > >> BPF_MEMLOCK_ADD limit.
> > > This is likely not related to rlimit. Can you check if unprivileged bpf
> > > is
> > > allowed:
> > >    cat /proc/sys/kernel/unprivileged_bpf_disabled
> > 
> > Hi Jan
> > 
> > Thanks for your quick reply. this value in my system is 1.
> > unprivileged bpf isn't allowed. Do we need to check it before run in case?
> 
> Yes, we should check that and TCONF, or better still run test without
> dropping CAP_SYS_ADMIN.

I added a hint to TCONF message, to have a look at unprivileged_bpf_disabled.