drm/radeon: Make r100_cp_ring_info() and radeon_ring_gfx() safe (v2)
authorAlex Ivanov <gnidorah@p0n4ik.tk>
Fri, 20 Sep 2013 13:36:06 +0000 (17:36 +0400)
committerAlex Deucher <alexander.deucher@amd.com>
Fri, 20 Sep 2013 21:34:52 +0000 (17:34 -0400)
commit0eb3448aa6b31fbf24c31756aba7940cac5ad6b8
tree0ca178740172d26985af7ddf8325e85a544835be
parent42baf21d91d4f52f5b9a4d11dc8e7b1e3b93de7c
drm/radeon: Make r100_cp_ring_info() and radeon_ring_gfx() safe (v2)

Prevent NULL pointer dereference in case when radeon_ring_fini() did it's job.

Reading of r100_cp_ring_info and radeon_ring_gfx debugfs entries will lead to a KP if ring buffer was deallocated, e.g. on failed ring test.
Seen on PA-RISC machine having "radeon: ring test failed (scratch(0x8504)=0xCAFEDEAD)" issue.

v2: agd5f: add some parens around ring->ready check

Signed-off-by: Alex Ivanov <gnidorah@p0n4ik.tk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
drivers/gpu/drm/radeon/r100.c
drivers/gpu/drm/radeon/radeon_ring.c