drm/msm/a6xx: move preempt_prepare_postamble after error check

Move the call to preempt_prepare_postamble() after verifying that
preempt_postamble_ptr is valid. If preempt_postamble_ptr is NULL,
dereferencing it in preempt_prepare_postamble() would lead to a crash.

This change avoids calling the preparation function when the
postamble allocation has failed, preventing potential NULL pointer
dereference and ensuring proper error handling.

Fixes: 50117cad0c50 ("drm/msm/a6xx: Use posamble to reset counters on preemption")
Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Patchwork: https://patchwork.freedesktop.org/patch/687659/
Message-ID: <20251113082839.3821867-1-alok.a.tiwari@oracle.com>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
index afc5f4aa3b17334027f3c20072cc3f059a9733b7..747a22afad9f6fe2c7848e787bab67155b92e71c 100644 (file)
--- a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
@@ -454,11 +454,11 @@ void a6xx_preempt_init(struct msm_gpu *gpu)
                        gpu->vm, &a6xx_gpu->preempt_postamble_bo,
                        &a6xx_gpu->preempt_postamble_iova);
 
-       preempt_prepare_postamble(a6xx_gpu);
-
        if (IS_ERR(a6xx_gpu->preempt_postamble_ptr))
                goto fail;
 
+       preempt_prepare_postamble(a6xx_gpu);
+
        timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
 
        return;