diff options
| author | Stephen Warren <swarren@nvidia.com> | 2011-01-05 21:24:12 (GMT) |
|---|---|---|
| committer | Colin Cross <ccross@android.com> | 2011-02-19 22:35:52 (GMT) |
| commit | 499ef7a5c48ea9fe8034b61de304ce9f6b753fe7 (patch) | |
| tree | f1ca0f89104dab39f3152a06d7b797ed181a17d8 /arch/arm/mach-tegra/dma.c | |
| parent | fe92a026e30050d5c79b2d41274211550a14cb04 (diff) | |
| download | linux-499ef7a5c48ea9fe8034b61de304ce9f6b753fe7.tar.xz | |
ARM: tegra: Prevent requeuing in-progress DMA requests
If a request already in the queue is passed to tegra_dma_enqueue_req,
tegra_dma_req.node->{next,prev} will end up pointing to itself instead
of at tegra_dma_channel.list, which is the way a the end-of-list
should be set up. When the DMA request completes and is list_del'd,
the list head will still point at it, yet the node's next/prev will
contain the list poison values. When the next DMA request completes,
a kernel panic will occur when those poison values are dereferenced.
This makes the DMA driver more robust in the face of buggy clients.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Colin Cross <ccross@android.com>
Diffstat (limited to 'arch/arm/mach-tegra/dma.c')
| -rw-r--r-- | arch/arm/mach-tegra/dma.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/dma.c b/arch/arm/mach-tegra/dma.c index 250bc7b..4625e3a 100644 --- a/arch/arm/mach-tegra/dma.c +++ b/arch/arm/mach-tegra/dma.c @@ -311,6 +311,7 @@ int tegra_dma_enqueue_req(struct tegra_dma_channel *ch, struct tegra_dma_req *req) { unsigned long irq_flags; + struct tegra_dma_req *_req; int start_dma = 0; if (req->size > NV_DMA_MAX_TRASFER_SIZE || @@ -321,6 +322,13 @@ int tegra_dma_enqueue_req(struct tegra_dma_channel *ch, spin_lock_irqsave(&ch->lock, irq_flags); + list_for_each_entry(_req, &ch->list, node) { + if (req == _req) { + spin_unlock_irqrestore(&ch->lock, irq_flags); + return -EEXIST; + } + } + req->bytes_transferred = 0; req->status = 0; req->buffer_status = 0; |