Re: [PATCH] perf jevents: Raise exception for no definition of a arch std event

From: John Garry
Date: Mon Aug 21 2023 - 06:46:42 EST


On 10/08/2023 20:27, Ian Rogers wrote:
On Wed, Aug 9, 2023 at 10:11 PM Ilkka Koskinen
<ilkka@xxxxxxxxxxxxxxxxxxxxxx> wrote:


Hi John,

On Mon, 7 Aug 2023, John Garry wrote:
Recently Ilkka reported that the JSONs for the AmpereOne arm64-based
platform included a dud event which referenced a non-existent arch std
event [0].

I wish I had found the bug in my patch a long time ago but, in fact, it
was Dave Kleikamp who initially pointed it out to me and figured out the
difference between jevents.c and jevents.py when porting the patch to 5.15
kernel.

https://urldefense.com/v3/__http://lists.infradead.org/pipermail/linux-arm-kernel/2023-June/844874.html__;!!ACWV5N9M2RV99hQ!It9EhKK4s2uBUJyQvLg-ruUfENAA6Sw7TWVo_hF8XmFoQ6q565iYafTnN-yoBNh3EQ1IFa2tHknUjNHs5dI$


Previously in the times of jevents.c, we would raise an exception for this.

This is still invalid, even though the current code just ignores such an
event.

Re-introduce code to raise an exception for when no definition exists to
help catch as many invalid JSONs as possible.

[0] https://urldefense.com/v3/__https://lore.kernel.org/linux-perf-users/9e851e2a-26c7-ba78-cb20-be4337b2916a@xxxxxxxxxx/__;!!ACWV5N9M2RV99hQ!It9EhKK4s2uBUJyQvLg-ruUfENAA6Sw7TWVo_hF8XmFoQ6q565iYafTnN-yoBNh3EQ1IFa2tHknU_t28TiE$

Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>

Thanks for the patch! I quickly tested it and it worked as expected. Just
in case this is needed:

Tested-by: Ilkka Koskinen <ilkka@xxxxxxxxxxxxxxxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Hi Arnaldo,

Can you consider applying this patch along with https://lore.kernel.org/linux-perf-users/CAP-5=fX2uE=B_Vb90nn5EV0mw+AJBpjDecP9w29OUn=j7HKPPg@xxxxxxxxxxxxxx/

I think that we should expect another version of that series with changes elsewhere.

Thanks,
John


Thanks,
Ian

Cheers, Ilkka

---
Please do not apply before [0], above.

diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py
index 8cd561aa606a..98cccc3fcbbd 100755
--- a/tools/perf/pmu-events/jevents.py
+++ b/tools/perf/pmu-events/jevents.py
@@ -347,12 +347,15 @@ class JsonEvent:
if self.desc and not self.desc.endswith('. '):
self.desc += '. '
self.desc = (self.desc if self.desc else '') + ('Unit: ' + self.pmu + ' ')
- if arch_std and arch_std.lower() in _arch_std_events:
- event = _arch_std_events[arch_std.lower()].event
- # Copy from the architecture standard event to self for undefined fields.
- for attr, value in _arch_std_events[arch_std.lower()].__dict__.items():
- if hasattr(self, attr) and not getattr(self, attr):
- setattr(self, attr, value)
+ if arch_std:
+ if arch_std.lower() in _arch_std_events:
+ event = _arch_std_events[arch_std.lower()].event
+ # Copy from the architecture standard event to self for undefined fields.
+ for attr, value in _arch_std_events[arch_std.lower()].__dict__.items():
+ if hasattr(self, attr) and not getattr(self, attr):
+ setattr(self, attr, value)
+ else:
+ raise argparse.ArgumentTypeError('Cannot find arch std event:', arch_std)

self.event = real_event(self.name, event)

--
2.35.3