Re: Linux 5.11-rc2

[Andrii Nakryiko]

On Fri, Jan 8, 2021 at 3:12 AM Christopher William Snowhill
<chris@xxxxxxxxxx> wrote:
>
> There appears to be a regression with the filesystem NLS modules. I cannot load any of them. They all produce:
>
> modprobe: ERROR: could not insert 'nls_cp437': Invalid argument
>
> The system journal reports:
>
> Jan 08 02:04:56 mrgency kernel: BPF:No data
> Jan 08 02:04:56 mrgency kernel: failed to validate module [nls_cp437] BTF: -22
>

Seems like you are getting module BTF with absolutely no types and
strings, and BTF verification fails for such case (currently). Can you
please share your .config, and also let me know what version of pahole
do you have (pahole --version)? Thanks!

The fix is to allow such "empty" BTF, most probably, but I'd like to
double-check nothing fishy is going on before that.

> As a result, I cannot mount vfat filesystems with the usual CP437 default. Or any other code page, for that matter.