In qxl_crtc_atomic_flush(), there is an if statement on line 376 to
check whether crtc->state is NULL:
if (crtc->state && crtc->state->event)
When crtc->state is NULL and qxl_crtc_update_monitors_config() is call,
qxl_crtc_update_monitors_config() uses crtc->state on line 326:
if (crtc->state->active)
and on line 358:
DRM_DEBUG_KMS(..., crtc->state->active, ...);
Thus, possible null-pointer dereferences may occur.
To fix these bugs, crtc->state is checked before calling
qxl_crtc_update_monitors_config().
These bugs are found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
---
drivers/gpu/drm/qxl/qxl_display.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 8b319ebbb0fb..fae18ef1ba59 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -382,7 +382,8 @@ static void qxl_crtc_atomic_flush(struct drm_crtc *crtc,
spin_unlock_irqrestore(&dev->event_lock, flags);
}
- qxl_crtc_update_monitors_config(crtc, "flush");
+ if (crtc->state)
+ qxl_crtc_update_monitors_config(crtc, "flush");
}
static void qxl_crtc_destroy(struct drm_crtc *crtc)
--
2.17.0
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