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commit40b697e256upstream. The GC860 has one GPU device which has a 2d and 3d core. In this case we want to expose perfmon information for both cores. The driver has one array which contains all possible perfmon domains with some meta data - doms_meta. Here we can see that for the GC860 two elements of that array are relevant: doms_3d: is at index 0 in the doms_meta array with 8 perfmon domains doms_2d: is at index 1 in the doms_meta array with 1 perfmon domain The userspace driver wants to get a list of all perfmon domains and their perfmon signals. This is done by iterating over all domains and their signals. If the userspace driver wants to access the domain with id 8 the kernel driver fails and returns invalid data from doms_3d with and invalid offset. This results in: Unable to handle kernel paging request at virtual address 00000000 On such a device it is not possible to use the userspace driver at all. The fix for this off-by-one error is quite simple. Reported-by: Paul Cercueil <paul@crapouillou.net> Tested-by: Paul Cercueil <paul@crapouillou.net> Fixes:ed1dd899ba("drm/etnaviv: rework perfmon query infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com> Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.