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Subject[PATCH 2/2] habanalabs: fix dma-buf release handling if dma_buf_fd() fails
Date
From: Tomer Tayar <ttayar@habana.ai>

The dma-buf private object is freed if a call to dma_buf_fd() fails,
and because a file was already associated with the dma-buf in
dma_buf_export(), the release op will be called and will use this
object.

Mark the 'priv' field as NULL in this case, and avoid accessing it from
the release op.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
---
drivers/misc/habanalabs/common/memory.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/habanalabs/common/memory.c b/drivers/misc/habanalabs/common/memory.c
index 693456366753..a2d24c9a3d1e 100644
--- a/drivers/misc/habanalabs/common/memory.c
+++ b/drivers/misc/habanalabs/common/memory.c
@@ -1782,7 +1782,12 @@ static void hl_unmap_dmabuf(struct dma_buf_attachment *attachment,
static void hl_release_dmabuf(struct dma_buf *dmabuf)
{
struct hl_dmabuf_priv *hl_dmabuf = dmabuf->priv;
- struct hl_ctx *ctx = hl_dmabuf->ctx;
+ struct hl_ctx *ctx;
+
+ if (!hl_dmabuf)
+ return;
+
+ ctx = hl_dmabuf->ctx;

if (hl_dmabuf->memhash_hnode) {
mutex_lock(&ctx->mem_hash_lock);
@@ -1822,7 +1827,7 @@ static int export_dmabuf(struct hl_ctx *ctx,

fd = dma_buf_fd(hl_dmabuf->dmabuf, flags);
if (fd < 0) {
- dev_err(hdev->dev, "failed to get a file descriptor for a dma-buf\n");
+ dev_err(hdev->dev, "failed to get a file descriptor for a dma-buf, %d\n", fd);
rc = fd;
goto err_dma_buf_put;
}
@@ -1835,6 +1840,7 @@ static int export_dmabuf(struct hl_ctx *ctx,
return 0;

err_dma_buf_put:
+ hl_dmabuf->dmabuf->priv = NULL;
dma_buf_put(hl_dmabuf->dmabuf);
return rc;
}
--
2.34.1
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