drm/msm/dpu: don't mix devm and drmm functions

Mixing devm and drmm functions will result in a use-after-free on msm
driver teardown if userspace keeps a reference on the drm device:
The WB connector data will be destroyed because of the use of
devm_kzalloc()), while the usersoace still can try interacting with the
WB connector (which uses drmm_ functions).

Change dpu_writeback_init() to use drmm_.

Fixes: 0b37ac63fc9d ("drm/msm/dpu: use drmm_writeback_connector_init()")
Reported-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Closes: https://lore.kernel.org/r/78c764b8-44cf-4db5-88e7-807a85954518@wanadoo.fr
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: John.Harrison@Igalia.com
Patchwork: https://patchwork.freedesktop.org/patch/722656/
Link: https://lore.kernel.org/r/20260505-wb-drop-encoder-v5-1-42567b7c7af2@oss.qualcomm.com

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
index 7545c0293efbd8f7eb34a4ac56f616b7cadae1c0..6f2370c9dd988d9d6bcda4c1e7c6c4deb7236093 100644 (file)
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
@@ -5,6 +5,7 @@
 
 #include <drm/drm_edid.h>
 #include <drm/drm_framebuffer.h>
+#include <drm/drm_managed.h>
 
 #include "dpu_writeback.h"
 
@@ -125,7 +126,7 @@ int dpu_writeback_init(struct drm_device *dev, struct drm_encoder *enc,
        struct dpu_wb_connector *dpu_wb_conn;
        int rc = 0;
 
-       dpu_wb_conn = devm_kzalloc(dev->dev, sizeof(*dpu_wb_conn), GFP_KERNEL);
+       dpu_wb_conn = drmm_kzalloc(dev, sizeof(*dpu_wb_conn), GFP_KERNEL);
        if (!dpu_wb_conn)
                return -ENOMEM;