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authorChristian König <christian.koenig@amd.com>2022-01-19 13:40:21 +0300
committerChristian König <christian.koenig@amd.com>2022-02-08 11:20:09 +0300
commit0fd9803b985e5d94e2b9f1848a12756b7848b62d (patch)
treef7eeab2f2bfe1114b2695c73fb174bb02ee7af28 /drivers/dma-buf
parent976b6d97c62347df3e686f60a5f455bb8ed6ea23 (diff)
downloadlinux-0fd9803b985e5d94e2b9f1848a12756b7848b62d.tar.xz
dma-buf: warn about dma_fence_array container rules v2
It's not allowed to nest another dma_fence container into a dma_fence_array or otherwise we can run into recursion. Warn about that when we create a dma_fence_array. v2: fix comment style and typo in the warning pointed out by Thomas Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220204100429.2049-3-christian.koenig@amd.com
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/dma-fence-array.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c
index 3e07f961e2f3..cb1bacb5a42b 100644
--- a/drivers/dma-buf/dma-fence-array.c
+++ b/drivers/dma-buf/dma-fence-array.c
@@ -176,6 +176,20 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
array->base.error = PENDING_ERROR;
+ /*
+ * dma_fence_array objects should never contain any other fence
+ * containers or otherwise we run into recursion and potential kernel
+ * stack overflow on operations on the dma_fence_array.
+ *
+ * The correct way of handling this is to flatten out the array by the
+ * caller instead.
+ *
+ * Enforce this here by checking that we don't create a dma_fence_array
+ * with any container inside.
+ */
+ while (num_fences--)
+ WARN_ON(dma_fence_is_container(fences[num_fences]));
+
return array;
}
EXPORT_SYMBOL(dma_fence_array_create);