This is a note to let you know that I've just added the patch titled
drm/amdgpu: fix fence slab teardown
to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amdgpu-fix-fence-slab-teardown.patch
and it can be found in the queue-4.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0f10425e811355986907c54f7d1d06703e406092 Mon Sep 17 00:00:00 2001
From: Grazvydas Ignotas <notasas@xxxxxxxxx>
Date: Sun, 23 Oct 2016 21:31:43 +0300
Subject: drm/amdgpu: fix fence slab teardown
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Grazvydas Ignotas <notasas@xxxxxxxxx>
commit 0f10425e811355986907c54f7d1d06703e406092 upstream.
To free fences, call_rcu() is used, which calls amdgpu_fence_free()
after a grace period. During teardown, there is no guarantee all
callbacks have finished, so amdgpu_fence_slab may be destroyed before
all fences have been freed. If we are lucky, this results in some slab
warnings, if not, we get a crash in one of rcu threads because callback
is called after amdgpu has already been unloaded.
Fix it with a rcu_barrier().
Fixes: b44135351a3a ("drm/amdgpu: RCU protected amdgpu_fence_release")
Acked-by: Chunming Zhou <david1.zhou@xxxxxxx>
Reviewed-by: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Grazvydas Ignotas <notasas@xxxxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -68,6 +68,7 @@ int amdgpu_fence_slab_init(void)
void amdgpu_fence_slab_fini(void)
{
+ rcu_barrier();
kmem_cache_destroy(amdgpu_fence_slab);
}
/*
Patches currently in stable-queue which might be from notasas@xxxxxxxxx are
queue-4.8/drm-amdgpu-fix-fence-slab-teardown.patch
queue-4.8/drm-amdgpu-fix-sched-fence-slab-teardown.patch
queue-4.8/drm-amd-fix-scheduler-fence-teardown-order-v2.patch
queue-4.8/drm-amdgpu-fix-a-vm_flush-fence-leak.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html