drm/radeon/vm: don't attempt to update ptes if ib allocation fails

commit 4cc948b94a222c310ae089c36718aac7a03aec90 upstream.

If we fail to allocate an indirect buffer (ib) when updating
the ptes, return an error instead of trying to use the ib.
Avoids a null pointer dereference.

Bug:
https://bugzilla.kernel.org/show_bug.cgi?id=58621

v2 (chk): rebased on drm-fixes-3.12 for stable inclusion

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/radeon/radeon_gart.c b/drivers/gpu/drm/radeon/radeon_gart.c
index 5ce190b..2915a1c 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_gart.c
+++ b/drivers/gpu/drm/radeon/radeon_gart.c
@@ -1157,6 +1157,8 @@ int radeon_vm_bo_update_pte(struct radeon_device *rdev,
                return -ENOMEM;
 
        r = radeon_ib_get(rdev, ridx, &ib, NULL, ndw * 4);
+       if (r)
+               return r;
        ib.length_dw = 0;
 
        r = radeon_vm_update_pdes(rdev, vm, &ib, bo_va->soffset, bo_va->eoffset);