exercising current aarch64 kprobe support with systemtap

[David Long]

On 06/23/2016 11:49 AM, William Cohen wrote:
> On 06/22/2016 11:18 PM, David Long wrote:
>> On 06/22/2016 04:24 PM, William Cohen wrote:
>>> Hi all,
>>>
>>> When running the current systemtap checked out from the git repository
>>> and a locally built kernel with the kprobes64-v13 patches (the
>>> test_upstream_arm64_devel branch of
>>> https://github.com/pratyushanand/linux) on Fedora 23 machine one of
>>> the kprobes_onthefly.exp tests is causing the machine to get in a
>>> state that requires rebooting to fix.  This can be triggered by running a
>>> portion of the systemtap tests with:
>>>
>>>    make installcheck RUNTESTFLAGS="--debug systemtap.onthefly/kprobes_onthefly.exp"
>>>
>>> When it gets to the kprobes_onthefly - otf_stress_max_iter_5000 test the
>>> console starts spewing the following and needs to be rebooted:
>>>
>>> [23394.036860] Unexpected kernel single-step exception at EL1
>>> [23394.042434] Unexpected kernel single-step exception at EL1
>>> [23394.048008] Unexpected kernel single-step exception at EL1
>>> [23394.053541] Unexpected kernel single-step exception at EL1
>>> [23394.059053] Unexpected kernel single-step exception at EL1
>>> [23394.064545] Unexpected kernel single-step exception at EL1
>>>
>>> Sorry I don't have the start of the failure it scrolled off the screen very quickly.
>>>
>>> -Will
>>>
>>>
>>
>> I'll take a look and see what I can figure out.
>>
>> In the meantime I did just push a v14 branch.  I'm doubtful that it will address the above problem even though it contains a few bug fixes.
>>
>> -dl
>>
>
> Hi Dave and Pratyush,
>
> I tried the kprobes64-v13 kernel and it also seems to work, so it lookw like the problem might be in the the
> test_upstream_arm64_devel branch of https://github.com/pratyushanand/linux .
>
> -Will
>

I'm going to interpret that as meaning you know of no problem in the 
kprobes v14 patch that would give me pause to email it upstream.  Do you 
disagree?

-dl