* [PATCH] iommu/dart: add missing put_device() call in apple_dart_of_xlate
@ 2025-07-12 16:16 Zhang Shurong
2025-07-12 18:22 ` Markus Elfring
2025-07-14 11:23 ` Will Deacon
0 siblings, 2 replies; 3+ messages in thread
From: Zhang Shurong @ 2025-07-12 16:16 UTC (permalink / raw)
To: sven
Cc: j, alyssa, neal, joro, will, robin.murphy, asahi,
linux-arm-kernel, iommu, linux-kernel, Zhang Shurong
The apple_dart_of_xlate() function obtains a platform device reference
via of_find_device_by_node() but doesn't release it with put_device().
This patch adds proper device reference handling to prevent memory
leaks.
Fixes: 46d1fb072e76 ("iommu/dart: Add DART iommu driver")
Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
---
drivers/iommu/apple-dart.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 190f28d76615..811bf5176568 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -796,8 +796,10 @@ static int apple_dart_of_xlate(struct device *dev,
if (!cfg) {
cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
- if (!cfg)
+ if (!cfg) {
+ put_device(&iommu_pdev->dev);
return -ENOMEM;
+ }
/* Will be ANDed with DART capabilities */
cfg->supports_bypass = true;
}
@@ -805,8 +807,10 @@ static int apple_dart_of_xlate(struct device *dev,
cfg_dart = cfg->stream_maps[0].dart;
if (cfg_dart) {
- if (cfg_dart->pgsize != dart->pgsize)
+ if (cfg_dart->pgsize != dart->pgsize) {
+ put_device(&iommu_pdev->dev);
return -EINVAL;
+ }
}
cfg->supports_bypass &= dart->supports_bypass;
@@ -825,6 +829,8 @@ static int apple_dart_of_xlate(struct device *dev,
}
}
+
+ put_device(&iommu_pdev->dev);
return -EINVAL;
}
--
2.39.5
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] iommu/dart: add missing put_device() call in apple_dart_of_xlate
2025-07-12 16:16 [PATCH] iommu/dart: add missing put_device() call in apple_dart_of_xlate Zhang Shurong
@ 2025-07-12 18:22 ` Markus Elfring
2025-07-14 11:23 ` Will Deacon
1 sibling, 0 replies; 3+ messages in thread
From: Markus Elfring @ 2025-07-12 18:22 UTC (permalink / raw)
To: Zhang Shurong, asahi, iommu, linux-arm-kernel
Cc: LKML, Alyssa Rosenzweig, Janne Grunau, Jörg Rödel,
Neal Gompa, Robin Murphy, Sven Peter, Will Deacon
> The apple_dart_of_xlate() function obtains a platform device reference
> via of_find_device_by_node() but doesn't release it with put_device().
> This patch adds proper device reference handling to prevent memory
> leaks.
Will another goto chain become helpful here?
See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.16-rc5#n94
Under which circumstances can the application of the attribute “put_device” grow?
https://elixir.bootlin.com/linux/v6.16-rc5/source/include/linux/device.h#L1140
Regards,
Markus
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] iommu/dart: add missing put_device() call in apple_dart_of_xlate
2025-07-12 16:16 [PATCH] iommu/dart: add missing put_device() call in apple_dart_of_xlate Zhang Shurong
2025-07-12 18:22 ` Markus Elfring
@ 2025-07-14 11:23 ` Will Deacon
1 sibling, 0 replies; 3+ messages in thread
From: Will Deacon @ 2025-07-14 11:23 UTC (permalink / raw)
To: Zhang Shurong
Cc: sven, j, alyssa, neal, joro, robin.murphy, asahi,
linux-arm-kernel, iommu, linux-kernel
On Sun, Jul 13, 2025 at 12:16:24AM +0800, Zhang Shurong wrote:
> The apple_dart_of_xlate() function obtains a platform device reference
> via of_find_device_by_node() but doesn't release it with put_device().
> This patch adds proper device reference handling to prevent memory
> leaks.
>
> Fixes: 46d1fb072e76 ("iommu/dart: Add DART iommu driver")
> Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
> ---
> drivers/iommu/apple-dart.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 190f28d76615..811bf5176568 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -796,8 +796,10 @@ static int apple_dart_of_xlate(struct device *dev,
>
> if (!cfg) {
> cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
> - if (!cfg)
> + if (!cfg) {
> + put_device(&iommu_pdev->dev);
> return -ENOMEM;
> + }
> /* Will be ANDed with DART capabilities */
> cfg->supports_bypass = true;
> }
> @@ -805,8 +807,10 @@ static int apple_dart_of_xlate(struct device *dev,
>
> cfg_dart = cfg->stream_maps[0].dart;
> if (cfg_dart) {
> - if (cfg_dart->pgsize != dart->pgsize)
> + if (cfg_dart->pgsize != dart->pgsize) {
> + put_device(&iommu_pdev->dev);
> return -EINVAL;
> + }
> }
>
> cfg->supports_bypass &= dart->supports_bypass;
> @@ -825,6 +829,8 @@ static int apple_dart_of_xlate(struct device *dev,
> }
> }
>
> +
> + put_device(&iommu_pdev->dev);
> return -EINVAL;
Why is it correct to retain the reference on the device in the cases
where this function returns 0?
Will
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-07-12 16:16 [PATCH] iommu/dart: add missing put_device() call in apple_dart_of_xlate Zhang Shurong
2025-07-12 18:22 ` Markus Elfring
2025-07-14 11:23 ` Will Deacon
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