From: Luca Ceresoli luca.ceresoli@bootlin.com
chan->mipi takes the return value of tegra_mipi_request() which can be a valid pointer or an error. However chan->mipi is checked in several places, including error-cleanup code in tegra_csi_channels_cleanup(), as 'if (chan->mipi)', which suggests the initial intent was that chan->mipi should be either NULL or a valid pointer, never an error. As a consequence, cleanup code in case of tegra_mipi_request() errors would dereference an invalid pointer.
Fix by ensuring chan->mipi always contains either NULL or a void pointer.
Also add that to the documentation.
Fixes: 523c857e34ce ("media: tegra-video: Add CSI MIPI pads calibration") Cc: stable@vger.kernel.org Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Luca Ceresoli luca.ceresoli@bootlin.com
---
This patch was added in v2. --- drivers/staging/media/tegra-video/csi.c | 1 + drivers/staging/media/tegra-video/csi.h | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/media/tegra-video/csi.c b/drivers/staging/media/tegra-video/csi.c index b26e44adb2be..6b59ef55c525 100644 --- a/drivers/staging/media/tegra-video/csi.c +++ b/drivers/staging/media/tegra-video/csi.c @@ -448,6 +448,7 @@ static int tegra_csi_channel_alloc(struct tegra_csi *csi, chan->mipi = tegra_mipi_request(csi->dev, node); if (IS_ERR(chan->mipi)) { ret = PTR_ERR(chan->mipi); + chan->mipi = NULL; dev_err(csi->dev, "failed to get mipi device: %d\n", ret); }
diff --git a/drivers/staging/media/tegra-video/csi.h b/drivers/staging/media/tegra-video/csi.h index 4ee05a1785cf..6960ea2e3d36 100644 --- a/drivers/staging/media/tegra-video/csi.h +++ b/drivers/staging/media/tegra-video/csi.h @@ -56,7 +56,7 @@ struct tegra_csi; * @framerate: active framerate for TPG * @h_blank: horizontal blanking for TPG active format * @v_blank: vertical blanking for TPG active format - * @mipi: mipi device for corresponding csi channel pads + * @mipi: mipi device for corresponding csi channel pads, or NULL if not applicable (TPG, error) * @pixel_rate: active pixel rate from the sensor on this channel */ struct tegra_csi_channel {
From: Luca Ceresoli luca.ceresoli@bootlin.com
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: 1ebaeb09830f ("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
---
No changes in v2. --- drivers/staging/media/tegra-video/csi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/media/tegra-video/csi.c b/drivers/staging/media/tegra-video/csi.c index 6b59ef55c525..426e653bd55d 100644 --- a/drivers/staging/media/tegra-video/csi.c +++ b/drivers/staging/media/tegra-video/csi.c @@ -433,7 +433,7 @@ static int tegra_csi_channel_alloc(struct tegra_csi *csi, for (i = 0; i < chan->numgangports; i++) chan->csi_port_nums[i] = port_num + i * CSI_PORTS_PER_BRICK;
- chan->of_node = node; + chan->of_node = of_node_get(node); chan->numpads = num_pads; if (num_pads & 0x2) { chan->pads[0].flags = MEDIA_PAD_FL_SINK; @@ -641,6 +641,7 @@ static void tegra_csi_channels_cleanup(struct tegra_csi *csi) media_entity_cleanup(&subdev->entity); }
+ of_node_put(chan->of_node); list_del(&chan->list); kfree(chan); }
linux-stable-mirror@lists.linaro.org
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luca.ceresoli＠bootlin.com