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30db77e018
The Iris code that deals with implicit tracking is protected by
bufmgr->bo_deps_lock. Before this patch, we hold this lock during
update_batch_syncobjs() but don't keep it held until we actually
submit the batch in the execbuf ioctl. This can lead to the following
race condition:
- Context C1 generates a batch B1 that signals syncobj S1.
- Context C2 generates a batch B2 that depends on something that B1
from C1 is using, so we mark B2 as having to wait syncobj S1.
- C2 calls submit_batch() before C1 does it.
- The Kernel detects it was told to wait on syncobj S1 that was
never even submitted, so it returns EINVAL to the execbuf ioctl.
- We run abort() at the end of _iris_batch_flush().
- If DEBUG is defined, we also print:
iris: Failed to submit batchbuffer: Invalid argument
I couldn't figure out a way to reproduce this issue with real
workloads, but I was able to write a small reproducer to trigger this.
Basically it's a little GL program that has lots of contexts running
in different threads submitting compute shaders that keep using the
same SSBOs. I'll submit this as a piglit test. Edit: Tapani found a
dEQP test case which fails intermintently without this fix, so I'm not
sure a new Piglit is worth it now.
The solution itself is quite simple: just keep bo_deps_lock held all
the way from update_batch_syncobjs() until ioctl(). In order to make
that easier we just call update_batch_syncobjs() a little later. We
have to drop the lock as soon as the ioctl returns because removing
the references on the buffers would trigger other functions to try to
grab the lock again, leading to deadlocks.
Thanks to Kenneth Graunke for pointing out this issue.
This has also been confirmed to fix a dEQP test that was giving
intermittent failures:
dEQP-EGL.functional.sharing.gles2.multithread.random.images.copyteximage2d.12
v2: Move decode_batch() out, just to be safe (Jason).
v3: Do it all after assembling validation_list (Ken).
Cc: mesa-stable
Fixes:
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| .gitlab/issue_templates | ||
| .gitlab-ci | ||
| android | ||
| bin | ||
| build-support | ||
| docs | ||
| include | ||
| src | ||
| subprojects | ||
| .dir-locals.el | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| .mailmap | ||
| .pick_status.json | ||
| .travis.yml | ||
| CODEOWNERS | ||
| meson.build | ||
| meson_options.txt | ||
| README.rst | ||
| VERSION | ||
`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library ====================================================== Source ------ This repository lives at https://gitlab.freedesktop.org/mesa/mesa. Other repositories are likely forks, and code found there is not supported. Build & install --------------- You can find more information in our documentation (`docs/install.rst <https://mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.rst <https://mesa3d.org/meson.html>`_): .. code-block:: sh $ mkdir build $ cd build $ meson .. $ sudo ninja install Support ------- Many Mesa devs hang on IRC; if you're not sure which channel is appropriate, you should ask your question on `OFTC's #dri-devel <irc://irc.oftc.net/dri-devel>`_, someone will redirect you if necessary. Remember that not everyone is in the same timezone as you, so it might take a while before someone qualified sees your question. To figure out who you're talking to, or which nick to ping for your question, check out `Who's Who on IRC <https://dri.freedesktop.org/wiki/WhosWho/>`_. The next best option is to ask your question in an email to the mailing lists: `mesa-dev\@lists.freedesktop.org <https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_ Bug reports ----------- If you think something isn't working properly, please file a bug report (`docs/bugs.rst <https://mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.rst <https://mesa3d.org/submittingpatches.html>`_). Note that Mesa uses gitlab for patches submission, review and discussions.