linux/drivers/gpu/drm
Laurent Pinchart f41ced8f10 Check fops_get() return value
Several subsystem open handlers dereference the fops_get() return value
without checking it for nullness.  This opens a race condition between the
open handler and module unloading.

A module can be marked as being unloaded (MODULE_STATE_GOING) before its
exit function is called and gets the chance to unregister the driver.
During that window open handlers can still be called, and fops_get() will
fail in try_module_get() and return a NULL pointer.

This change checks the fops_get() return value and returns -ENODEV if NULL.

Reported-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Acked-by: Takashi Iwai <tiwai@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Airlie <airlied@linux.ie>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:11 -08:00
..
i810 drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
i830 drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
i915 drm/i915: fix modeset devname allocation + agp init return check. 2008-12-29 18:18:19 +10:00
mga drm: move drm vblank initialization/cleanup to driver load/unload 2008-11-25 09:49:03 +10:00
r128 drm: move drm vblank initialization/cleanup to driver load/unload 2008-11-25 09:49:03 +10:00
radeon drm/radeon: use locked rmmap to remove sarea mapping. 2008-12-29 17:47:24 +10:00
savage drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
sis SiS DRM: fix a pointer cast warning 2008-10-18 07:10:10 +10:00
tdfx drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
via drm: move drm vblank initialization/cleanup to driver load/unload 2008-11-25 09:49:03 +10:00
ati_pcigart.c drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
drm_agpsupport.c i915: Map status page cached for chips with GTT-based HWS location. 2008-10-18 07:10:53 +10:00
drm_auth.c drm: move to kref per-master structures. 2008-12-29 17:47:22 +10:00
drm_bufs.c drm/radeon: use locked rmmap to remove sarea mapping. 2008-12-29 17:47:24 +10:00
drm_cache.c drm: wbinvd is cache coherent. 2008-10-18 07:10:53 +10:00
drm_context.c drm: move to kref per-master structures. 2008-12-29 17:47:22 +10:00
drm_crtc_helper.c drm: pin new and unpin old buffer when setting a mode. 2008-12-29 17:47:27 +10:00
drm_crtc.c drm: drop DRM_IOCTL_MODE_REPLACEFB, add+remove works just as well. 2008-12-29 17:47:25 +10:00
drm_dma.c drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
drm_drawable.c drm: Avoid oops in DRM_IOCTL_RM_DRAW if a bad handle is supplied. 2008-10-23 13:46:54 +10:00
drm_drv.c drm: Avoid use-before-null-test on dev in drm_cleanup(). 2008-12-29 17:47:27 +10:00
drm_edid.c drm: fix useless gcc unused variable warning 2008-12-29 17:47:24 +10:00
drm_fops.c Check fops_get() return value 2009-01-06 15:59:11 -08:00
drm_gem.c drm: PAGE_CACHE_WC is x86 only so far 2008-12-29 17:47:24 +10:00
drm_hashtab.c drm: GEM mmap support 2008-12-29 17:47:22 +10:00
drm_ioc32.c drm: Add 32-bit compatibility for DRM_IOCTL_UPDATE_DRAW. 2008-10-23 13:46:33 +10:00
drm_ioctl.c drm: fix leak of uninitialized data to userspace 2008-12-29 17:47:22 +10:00
drm_irq.c drm: Add a debug node for vblank state. 2008-12-29 17:47:27 +10:00
drm_lock.c drm: move to kref per-master structures. 2008-12-29 17:47:22 +10:00
drm_memory.c drm: Add GEM ("graphics execution manager") to i915 driver. 2008-10-18 07:10:12 +10:00
drm_mm.c DRM: add mode setting support 2008-12-29 17:47:23 +10:00
drm_modes.c DRM: add mode setting support 2008-12-29 17:47:23 +10:00
drm_pci.c drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
drm_proc.c drm: Add a debug node for vblank state. 2008-12-29 17:47:27 +10:00
drm_scatter.c drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
drm_sman.c drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
drm_stub.c DRM: add mode setting support 2008-12-29 17:47:23 +10:00
drm_sysfs.c DRM: add mode setting support 2008-12-29 17:47:23 +10:00
drm_vm.c drm: GEM mmap support 2008-12-29 17:47:22 +10:00
Kconfig drm: kconfig have drm core select i2c for kms 2008-12-29 17:47:24 +10:00
Makefile DRM: add mode setting support 2008-12-29 17:47:23 +10:00
README.drm drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00

************************************************************
* 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