On Mon, Aug 19, 2024 at 09:49:28PM +0200, Ulrich Mueller wrote:
> > I pushed a fix to virtualx.eclass for you.
> That addpredict looks like a workaround, not like a real fix of the
> problem.
It's a fix in that it correctly tells Sandbox that upstream mesas use a
predictive fopen(..., RDWR) and Gentoo expects it to *NOT* actually use the
device in the ebuild context.

> Especially, the many warnings mentioned by grozin are still
> there. With the patched virtualx.eclass, I still see more than thousand
> messages in Xvfb.log:
>    libEGL warning: failed to open /dev/dri/card0: Permission denied
The manual does correctly build despite that warning from mesa, because it
correctly falls back.

> Also, was this so urgent that you had to push the eclass change without
> prior mailing list review?
Low impact, fixes blockage.

Reminder to all, if you go looking for bugs, you'll find more than you expected.

Git bisect of mesa points to the relevant upstream commits that introduced the flaws.

1. The init behavior changed here: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30426/diffs
   This was added between mesa-24.2.0-rc3 and mesa-24.2.0-rc4
   It always probes those /dev/ files now.

2. I *also* found a similar failure upstream between 24.0.9 and 24.1.0; with USE=llvm specifically:
   https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27805/diffs#81e929dbdc766bd46257096f260549cbdeba18fc_1133_1161

sandbox snippet for USE=llvm:
F: open_wr
S: deny
P: /dev/udmabuf
A: /dev/udmabuf
R: /dev/udmabuf
C: Xvfb -displayfd 1 -screen 0 1280x1024x24 +extension RANDR 

"addpredict /dev/udmabuf" should also enable other cases to be stricter:
https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=48b4885e4f9a19ccc4c1489a387e38fb3b7d62b7

and re-enable tests here:
https://bugs.gentoo.org/933257

-- 
Robin Hugh Johnson
Gentoo Linux: Dev, Infra Lead, Foundation President & Treasurer
E-Mail   : robbat2@gentoo.org
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