When saving BOs in the hang state we skip one entry of the
kernel_state->bo[] array, thus leaving it to NULL. This leads to a NULL
pointer dereference when, later in this function, we iterate over all
BOs to check their ->madv state.
Fixes: ca26d28bbaa3 ("drm/vc4: improve throughput by pipelining binning and rendering jobs")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
---
Changes in v2:
- Get rid of prev_idx an replace it by k which is indepently incremented
every time a new object is added to kernel_state->bo[].
- Add a WARN_ON_ONCE() when final value of k is inconsistent
---
drivers/gpu/drm/vc4/vc4_gem.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 6c32c89a83a9..3216f12052fe 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -146,7 +146,7 @@ vc4_save_hang_state(struct drm_device *dev)
struct vc4_exec_info *exec[2];
struct vc4_bo *bo;
unsigned long irqflags;
- unsigned int i, j, unref_list_count, prev_idx;
+ unsigned int i, j, k, unref_list_count;
kernel_state = kcalloc(1, sizeof(*kernel_state), GFP_KERNEL);
if (!kernel_state)
@@ -182,7 +182,7 @@ vc4_save_hang_state(struct drm_device *dev)
return;
}
- prev_idx = 0;
+ k = 0;
for (i = 0; i < 2; i++) {
if (!exec[i])
continue;
@@ -197,7 +197,7 @@ vc4_save_hang_state(struct drm_device *dev)
WARN_ON(!refcount_read(&bo->usecnt));
refcount_inc(&bo->usecnt);
drm_gem_object_get(&exec[i]->bo[j]->base);
- kernel_state->bo[j + prev_idx] = &exec[i]->bo[j]->base;
+ kernel_state->bo[k++] = &exec[i]->bo[j]->base;
}
list_for_each_entry(bo, &exec[i]->unref_list, unref_head) {
@@ -205,12 +205,12 @@ vc4_save_hang_state(struct drm_device *dev)
* because they are naturally unpurgeable.
*/
drm_gem_object_get(&bo->base.base);
- kernel_state->bo[j + prev_idx] = &bo->base.base;
- j++;
+ kernel_state->bo[k++] = &bo->base.base;
}
- prev_idx = j + 1;
}
+ WARN_ON_ONCE(k != state->bo_count);
+
if (exec[0])
state->start_bin = exec[0]->ct0ca;
if (exec[1])
--
2.11.0
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