drm/amdgpu: don't access invalid sched

[ Upstream commit a93b1020eb9386d7da11608477121b10079c076a ]

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.

Fixes: 2320c9e6a768 ("drm/sched: memset() 'job' in drm_sched_job_init()")
Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 2ae520cb12831d264ceb97c61f72c59d33c0dbd7)
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index f34bc9bb7045a0e0f7d83a5cf1daa5403471d95c..7f1e92110dd1f8a733260f0f6cbac34c31d8ab05 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -150,7 +150,6 @@ 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;
 
@@ -163,7 +162,7 @@ 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)