[PATCH] drm/radeon: fix NULL pointer dereference in UMS mode

[Shuah Khan]

In UMS mode parser->rdev is NULL, so dereferencing
will cause an oops.

Upstream commit-id: ff4bd0827764e10a428a9d39e6814c5478863f94
Stable tree: 3.7

Signed-off-by: Ilija Hadzic <ihadzic at research.bell-labs.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Shuah Khan <shuah.khan at hp.com>
CC: stable at vger.kernel.org 3.7
---
 drivers/gpu/drm/radeon/radeon_cs.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_cs.c 
b/drivers/gpu/drm/radeon/radeon_cs.c
index 396baba..45151c4 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -279,7 +279,7 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void 
*data)
                                  p->chunks[p->chunk_ib_idx].length_dw);
                        return -EINVAL;
                }
-               if ((p->rdev->flags & RADEON_IS_AGP)) {
+               if (p->rdev && (p->rdev->flags & RADEON_IS_AGP)) {
                        p->chunks[p->chunk_ib_idx].kpage[0] = 
kmalloc(PAGE_SIZE, GFP_KERNEL);
                        p->chunks[p->chunk_ib_idx].kpage[1] = 
kmalloc(PAGE_SIZE, GFP_KERNEL);
                        if (p->chunks[p->chunk_ib_idx].kpage[0] == NULL ||
@@ -583,7 +583,8 @@ static int radeon_cs_update_pages(struct radeon_cs_parser 
*p, int pg_idx)
        struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];
        int i;
        int size = PAGE_SIZE;
-       bool copy1 = (p->rdev->flags & RADEON_IS_AGP) ? false : true;
+       bool copy1 = (p->rdev && (p->rdev->flags & RADEON_IS_AGP)) ?
+               false : true;

        for (i = ibc->last_copied_page + 1; i < pg_idx; i++) {
                if (DRM_COPY_FROM_USER(p->ib.ptr + (i * (PAGE_SIZE/4)),
-- 
1.7.9.5