On 3/18/25 12:25, Song Liu wrote:
> On Tue, Mar 18, 2025 at 6:45 AM Joe Lawrence <joe.lawrence@xxxxxxxxxx> wrote:
>>
>> On Tue, Mar 18, 2025 at 11:14:55AM +0100, Miroslav Benes wrote:
>>> Hi,
>>>
>>> On Mon, 17 Mar 2025, Song Liu wrote:
>>>
>>>> On Mon, Mar 17, 2025 at 11:59 AM Joe Lawrence <joe.lawrence@xxxxxxxxxx> wrote:
>>>>>
>>>>> On 3/17/25 12:51, Song Liu wrote:
>>>>>> CONFIG_KPROBES_ON_FTRACE is required for test-kprobe. Skip test-kprobe
>>>>>> when CONFIG_KPROBES_ON_FTRACE is not set.
>>>>>>
>>>>>> Signed-off-by: Song Liu <song@xxxxxxxxxx>
>>>>>> ---
>>>>>> tools/testing/selftests/livepatch/test-kprobe.sh | 2 ++
>>>>>> 1 file changed, 2 insertions(+)
>>>>>>
>>>>>> diff --git a/tools/testing/selftests/livepatch/test-kprobe.sh b/tools/testing/selftests/livepatch/test-kprobe.sh
>>>>>> index 115065156016..fd823dd5dd7f 100755
>>>>>> --- a/tools/testing/selftests/livepatch/test-kprobe.sh
>>>>>> +++ b/tools/testing/selftests/livepatch/test-kprobe.sh
>>>>>> @@ -5,6 +5,8 @@
>>>>>>
>>>>>> . $(dirname $0)/functions.sh
>>>>>>
>>>>>> +zgrep KPROBES_ON_FTRACE /proc/config.gz || skip "test-kprobe requires CONFIG_KPROBES_ON_FTRACE"
>>>>>> +
>>>>>
>>>>> Hi Song,
>>>>>
>>>>> This in turn depends on CONFIG_IKCONFIG_PROC for /proc/config.gz (not
>>>>> set for RHEL distro kernels).
>>>>
>>>> I was actually worrying about this when testing it.
>>>>
>>>>> Is there a dynamic way to figure out CONFIG_KPROBES_ON_FTRACE support?
>>>>
>>>> How about we grep kprobe_ftrace_ops from /proc/kallsyms?
>>>
>>> which relies on having KALLSYMS_ALL enabled but since CONFIG_LIVEPATCH
>>> depends on it, we are good. So I would say yes, it is a better option.
>>> Please, add a comment around.
>>>
>>
>> Kallsyms is a good workaround as kprobe_ftrace_ops should be stable (I
>> hope :)
>>
>> Since Song probably noticed this when upgrading and the new kprobes test
>> unexpectedly failed, I'd add a Fixes tag to help out backporters:
>>
>> Fixes: 62597edf6340 ("selftests: livepatch: test livepatching a kprobed function")
>>
>> but IMHO not worth rushing as important through the merge window.
>>
>>
>> Also, while poking at this today with virtme-ng, my initial attempt had
>> build a fairly minimal kernel without CONFIG_DYNAMIC_DEBUG. We can also
>> check for that via the sysfs interface to avoid confusing path-not-found
>> msgs, like the following ...
>
> We already have CONFIG_DYNAMIC_DEBUG=y in
> tools/testing/selftests/livepatch, so I think we don't need to check that again.
>
Ah right. Do you know what script/file reads or sources that file?
(It's such a generic term that I get a bazillion grep hits.) When I run
`make -C tools/testing/selftests/livepatch run_tests` it just builds and
runs the tests regardless of the actual config.
--
Joe
