On Fri, Apr 20, 2012 at 11:34:43AM +0100, Dave Airlie wrote:
I may be reading things wrong but the initialisation does indeed hold drm_global_mutex, but and back when this first occured we would have been using kernel_lock() which was at least partially reentrant right?
Yup if we slept with the BKL held we'd have allowed others to get past it, but also I introduced the global mutex in pci a while back
Yeah I have managed to get access to more details on the bug, and actually we are opening the drm device successfully, we then attempt a DRM_SETVERSION ioctl on it and it is that that appears to fail both for 1.4 and 1.1.
It is somewhat perplexing to understand how that is possible, though I will note that the stub f_ops do not contain an ioctl op but I cannot see any mechanism by which we might return a validly open file without putting the driver specific ops in it.
-apw