Since 2320c9e6a768 ("drm/sched: memset() 'job' in drm_sched_job_init()")
accessing job->base.sched can produce unexpected results as the initialisation
of (*job)->base.sched done in amdgpu_job_alloc is overwritten by the
memset.

This commit fixes an issue when a CS would fail validation and would
be rejected after job->num_ibs is incremented. In this case,
amdgpu_ib_free(ring->adev, ...) will be called, which would crash the
machine because the ring value is bogus.

To fix this, pass a NULL pointer to amdgpu_ib_free(): we can do this
because the device is actually not used in this function.

The next commit will remove the ring argument completely.

Signed-off-by: Pierre-Eric Pelloux-Prayer <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index 9b322569255e..9ec8d5a8e48c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -256,7 +256,6 @@ void amdgpu_job_set_resources(struct amdgpu_job *job, 
struct amdgpu_bo *gds,
 
 void amdgpu_job_free_resources(struct amdgpu_job *job)
 {
-       struct amdgpu_ring *ring = to_amdgpu_ring(job->base.sched);
        struct dma_fence *f;
        unsigned i;
 
@@ -269,7 +268,7 @@ void amdgpu_job_free_resources(struct amdgpu_job *job)
                f = NULL;
 
        for (i = 0; i < job->num_ibs; ++i)
-               amdgpu_ib_free(ring->adev, &job->ibs[i], f);
+               amdgpu_ib_free(NULL, &job->ibs[i], f);
 }
 
 static void amdgpu_job_free_cb(struct drm_sched_job *s_job)
-- 
2.43.0

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