Hal Gentz
1591d1fee5
When run in optirun, applications that linked to `libGLX.so` and then proceeded to querying Mesa for extension strings caused a SEGV in Mesa. `glXQueryExtensionsString` was calling a chain of functions that eventually led to `__glXQueryServerString`. This function would call `xcb_glx_query_server_string` then `xcb_glx_query_server_string_reply`. The latter for some unknown reason returned `NULL`. Passing this `NULL` to `xcb_glx_query_server_string_string_length` would cause a SEGV as the function tried to dereference it. The reason behind the function returning `NULL` is yet to be determined, however, simply checking that the ptr is not `NULL` resolves this. A similar check has been added to `__glXGetString` for completeness sake, although not immediately necessary. In addition to that, we stumbled into a similar problem in `AllocAndFetchScreenConfigs` which tries to access the configs to free them if `__glXQueryServerString` fails. This, of course, SEGVs, because the configs are yet to have been allocated. Simply continuing past the configs if their config ptrs are `NULL` resolves this. We also switch to `calloc` to make sure that the config ptrs are `NULL` by default, and not some uninitialized value. Cc: mesa-stable@lists.freedesktop.org Fixes:24b8a8cfe8"glx: implement __glXGetString, hide __glXGetStringFromServer" Fixes:cb3610e37c"Import the GLX client side library, formerly from xc/lib/GL/glx. Build it " Reviewed-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Hal Gentz <zegentzy@protonmail.com>
`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.html <https://mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.html <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 `Freenode's #dri-devel <irc://chat.freenode.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.html <https://mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.html <https://mesa3d.org/submittingpatches.html>`_). Note that Mesa uses email mailing-lists for patches submission, review and discussions.