staging: media: tegra-video: fix device_node use after free
[ Upstream commit c4d344163c3a7f90712525f931a6c016bbb35e18 ]
At probe time this code path is followed:
* tegra_csi_init
* tegra_csi_channels_alloc
* for_each_child_of_node(node, channel) -- iterates over channels
* automatically gets 'channel'
* tegra_csi_channel_alloc()
* saves into chan->of_node a pointer to the channel OF node
* automatically gets and puts 'channel'
* now the node saved in chan->of_node has refcount 0, can disappear
* tegra_csi_channels_init
* iterates over channels
* tegra_csi_channel_init -- uses chan->of_node
After that, chan->of_node keeps storing the node until the device is
removed.
of_node_get() the node and of_node_put() it during teardown to avoid any
risk.
Fixes: 1ebaeb0983
("media: tegra-video: Add support for external sensor capture")
Cc: stable@vger.kernel.org
Cc: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:

committed by
Greg Kroah-Hartman

parent
f899baf6cb
commit
5451efb2ca
@@ -420,7 +420,7 @@ static int tegra_csi_channel_alloc(struct tegra_csi *csi,
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chan->csi = csi;
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chan->csi_port_num = port_num;
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chan->numlanes = lanes;
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chan->of_node = node;
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chan->of_node = of_node_get(node);
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chan->numpads = num_pads;
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if (num_pads & 0x2) {
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chan->pads[0].flags = MEDIA_PAD_FL_SINK;
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@@ -621,6 +621,7 @@ static void tegra_csi_channels_cleanup(struct tegra_csi *csi)
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media_entity_cleanup(&subdev->entity);
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}
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of_node_put(chan->of_node);
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list_del(&chan->list);
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kfree(chan);
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}
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