diff options
| author | Lars-Peter Clausen <lars@metafoo.de> | 2026-07-15 08:42:44 -0700 |
|---|---|---|
| committer | Jonathan Cameron <jonathan.cameron@oss.qualcomm.com> | 2026-08-07 23:51:03 +0100 |
| commit | f25ec4627d935dedfb5fe83bd2c2678cdcc19611 (patch) | |
| tree | 486bbc66eda4a2f14944ed19da88a44e7fe2052d /drivers | |
| parent | 6288b593e76eb10329326f2cd51e32557203b9e5 (diff) | |
| download | linux-f25ec4627d935dedfb5fe83bd2c2678cdcc19611.tar.gz linux-f25ec4627d935dedfb5fe83bd2c2678cdcc19611.zip | |
iio: buffer: Tie IIO dma fence lock lifetime to the fence
The `iio_dma_fence` implementation currently uses a lock embedded in the
`iio_dmabuf_priv`. But the `iio_dma_fence` can outlive the
`iio_dmabuf_priv`, which can cause a use-after-free.
Tie the lifetime of the lock to the lifetime of the fence by embedding them
in the same struct.
We can't just hold a reference to the `iio_dmabuf_priv` from the
`iio_dma_fence` since `iio_buffer_dmabuf_release()` might sleep and the
fence release callback is not allowed to sleep.
Note that the `dma_fence` framework now has an internal lock that gets used
when the passing `NULL` for `lock` in `dma_fence_init()`, but in order to
allow this patch to be backportable use an external lock.
Reported-by: codex:gpt-5.6
Fixes: 3e26d9f08fbe ("iio: core: Add new DMABUF interface infrastructure")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/industrialio-buffer.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index 04b3916f89e2..31c06bffdce8 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -47,9 +47,6 @@ struct iio_dmabuf_priv { u64 context; - /* Spinlock used for locking the dma_fence */ - spinlock_t lock; - struct dma_buf_attachment *attach; struct sg_table *sgt; enum dma_data_direction dir; @@ -58,6 +55,7 @@ struct iio_dmabuf_priv { struct iio_dma_fence { struct dma_fence base; + spinlock_t lock; /* protects base */ struct iio_dmabuf_priv *priv; struct work_struct work; }; @@ -1706,7 +1704,6 @@ static int iio_buffer_attach_dmabuf(struct iio_dev_buffer_pair *ib, if (!priv) return -ENOMEM; - spin_lock_init(&priv->lock); priv->context = dma_fence_context_alloc(1); dmabuf = dma_buf_get(fd); @@ -1896,6 +1893,8 @@ static int iio_buffer_enqueue_dmabuf(struct iio_dev_buffer_pair *ib, goto err_attachment_put; } + spin_lock_init(&fence->lock); + fence->priv = priv; seqno = atomic_add_return(1, &priv->seqno); @@ -1906,7 +1905,7 @@ static int iio_buffer_enqueue_dmabuf(struct iio_dev_buffer_pair *ib, * the dma_fence. */ dma_fence_init(&fence->base, &iio_buffer_dma_fence_ops, - &priv->lock, priv->context, seqno); + &fence->lock, priv->context, seqno); ret = iio_dma_resv_lock(dmabuf, nonblock); if (ret) |