Re: mips:allmodconfig build failure in 3.16-rc1 due to bpf_jit code

[Markos Chandras <Markos.Chandras@imgtec.com>]

On 06/17/2014 11:56 AM, Daniel Borkmann wrote:
> On 06/17/2014 12:39 PM, Guenter Roeck wrote:
>> On 06/17/2014 03:16 AM, Daniel Borkmann wrote:
>>> On 06/17/2014 10:20 AM, Daniel Borkmann wrote:
>>>> On 06/17/2014 04:24 AM, Guenter Roeck wrote:
>>>>> mips:allmodconfig fails in 3.16-rc1 with lots of undefined symbols.
>>>>>
>>>>> arch/mips/net/bpf_jit.c: In function 'is_load_to_a':
>>>>> arch/mips/net/bpf_jit.c:559:7: error: 'BPF_S_LD_W_LEN' undeclared
>>>>> (first use in this function)
>>>>> arch/mips/net/bpf_jit.c:559:7: note: each undeclared identifier is
>>>>> reported only once for each function it appears in
>>>>> arch/mips/net/bpf_jit.c:560:7: error: 'BPF_S_LD_W_ABS' undeclared
>>>>> (first use in this function)
>>>>> arch/mips/net/bpf_jit.c:561:7: error: 'BPF_S_LD_H_ABS' undeclared
>>>>> (first use in this function)
>>>>> arch/mips/net/bpf_jit.c:562:7: error: 'BPF_S_LD_B_ABS' undeclared
>>>>> (first use in this function)
>>>>> arch/mips/net/bpf_jit.c:563:7: error: 'BPF_S_ANC_CPU' undeclared
>>>>> (first use in this function)
>>>>> arch/mips/net/bpf_jit.c:564:7: error: 'BPF_S_ANC_IFINDEX'
>>>>> undeclared (first use in this function)
>>>>> arch/mips/net/bpf_jit.c:565:7: error: 'BPF_S_ANC_MARK' undeclared
>>>>> (first use in this function)
>>>>>
>>>>> and so on.
>>>>>
>>>>> Those symbols are not defined anywhere.
>>>>>
>>>>> The problem is due to a conflict with commit 348059313 (net:
>>>>> filter: get rid of BPF_S_*
>>>>> enum), which removed those definitions.
>>>>
>>>> Yep, it seems both got in this merge window from different trees.
>>>> Don't have mips, but
>>>> I'll have a look, and send you a patch.
>>>
>>> Could you give the attached patch a try?
>>
>> Yes, this fixes the build problem. Obviously I have no idea if it
>> works ;-)
> 
> Thanks Guenter!
> 
> We have a test suite for BPF under lib/test_bpf.c that was designed for the
> interpreter and for BPF JIT developers in mind and pretty much covers most
> cases. E.g. one possibility to run it would be:
> 
>   0) compile module test_bpf (Kernel Hacking -> Test BPF filter
> functionality)
>   1) echo 1 > /proc/sys/net/core/bpf_jit_enable           [<- enables
> BPF JIT]
>   2) modprobe test_bpf                                    [<- runs test
> suite]
> 
> The results will be visible in the klog via dmesg (if at least one test
> fails,
> the module init handler will return an error).
> 
> Best,
> 
> Daniel
Hi Daniel,

Thanks for these instructions. I will try them myself once I find some
time since I don't think bpf_jit for MIPS has ever been tested with all
the opcodes.

-- 
markos