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commit c715089f49844260f1eeae8e3b55af9468ba1325 upstream. During a page fault and rebinding the buffer there exists a window for a signal to arrive during the i915_wait_request() and trigger a ERESTARTSYS. This used to be handled by returning SIGBUS and thereby killing the application. Try 'cairo-perf-trace & cairo-test-suite' and watch X go boom! The solution as suggested by H. Peter Anvin is to simply return NOPAGE and leave the higher layers to spot we did not fill the page and resubmit the page fault. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> [anholt: Mostly squash it with another commit] Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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* For the very latest on DRI development, please see: *
* http://dri.freedesktop.org/ *
************************************************************
The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).
The DRM supports the Direct Rendering Infrastructure (DRI) in four major
ways:
1. The DRM provides synchronized access to the graphics hardware via
the use of an optimized two-tiered lock.
2. The DRM enforces the DRI security policy for access to the graphics
hardware by only allowing authenticated X11 clients access to
restricted regions of memory.
3. The DRM provides a generic DMA engine, complete with multiple
queues and the ability to detect the need for an OpenGL context
switch.
4. The DRM is extensible via the use of small device-specific modules
that rely extensively on the API exported by the DRM module.
Documentation on the DRI is available from:
http://dri.freedesktop.org/wiki/Documentation
http://sourceforge.net/project/showfiles.php?group_id=387
http://dri.sourceforge.net/doc/
For specific information about kernel-level support, see:
The Direct Rendering Manager, Kernel Support for the Direct Rendering
Infrastructure
http://dri.sourceforge.net/doc/drm_low_level.html
Hardware Locking for the Direct Rendering Infrastructure
http://dri.sourceforge.net/doc/hardware_locking_low_level.html
A Security Analysis of the Direct Rendering Infrastructure
http://dri.sourceforge.net/doc/security_low_level.html