b1ed35d917
The fence registers are clobbered by a GPU reset. If there is concurrent user access to a fenced region via a GTT mmaping, the access will not be fenced during the reset (until we restore the fences afterwards). In order to prevent invalid access during the reset, before we clobber the fences first we must invalidate the GTT mmapings. Access to the mmap will then be forced to fault in the page, and in handling the fault, i915_gem_fault() will take the struct_mutex and wait upon the reset to complete. v2: Fix up commentary. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99274 Testcase: igt/gem_mmap_gtt/hang Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/20170104145110.1486-1-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.