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

[Yang Xu]

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?

>
>> How can I run the two cases normally? Also, this error log(requires
>> CAP_SYS_ADMIN on this system: EPERM
>> ) makes me confused in this situation(because case drops CAP_SYS_ADMIN, but
>> log reports need CAP_SYS_ADMIN)
>> and I think we may change it into "require CAP_SYS_ADMIN or max locked memory
>> limit is too low".
>>
>> Or, can I keep CAP_SYS_ADMIN cap in bpf_prog02/[3]?
>>
>>
>> Thanks
>> Yang Xu
>>    
>>
>>
>>
>>
>
>


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