Re: [PATCH hid v12 03/15] HID: initial BPF implementation

From: Jon Hunter
Date: Wed Nov 23 2022 - 13:47:45 EST


Hi Benjamin,

On 23/11/2022 14:48, Benjamin Tissoires wrote:

...

We have a kernel test that checks for new warning and error messages on
boot and with this change I am now seeing the following error message on
our Tegra platforms ...

WARNING KERN hid_bpf: error while preloading HID BPF dispatcher: -13

I have a quick look at the code, but I can't say I am familiar with
this. So I wanted to ask if a way to fix this or avoid this? I see the
code returns 0, so one option would be to make this an informational or
debug print.

I am not in favor of debug in that case, because I suspect it'll hide
too much when getting a bug report. Informational could do, yes.

However, before that, I'd like to dig a little bit more on why it is
failing. I thought arm64 now has support of tracing bpf programs, so I
would not expect this to fail.

Yes it would be great if we could figure out why this is failing.

Would you mind sending me your .config so I can check in it if you are
missing anything? I am thinking that maybe I need to also depend on
BPF_JIT.

It is basically the stock upstream arm64 defconfig, but I will forward offline.

Cheers
Jon

--
nvpublic