* [PATCH v2] dma: Fix a double free in dma_async_device_register
@ 2021-03-31 1:44 Lv Yunlong
2021-03-31 2:48 ` Dave Jiang
2021-04-12 9:36 ` Vinod Koul
0 siblings, 2 replies; 3+ messages in thread
From: Lv Yunlong @ 2021-03-31 1:44 UTC (permalink / raw)
To: vkoul, dave.jiang; +Cc: dmaengine, linux-kernel, Lv Yunlong
In the first list_for_each_entry() macro of dma_async_device_register,
it gets the chan from list and calls __dma_async_device_channel_register
(..,chan). We can see that chan->local is allocated by alloc_percpu() and
it is freed chan->local by free_percpu(chan->local) when
__dma_async_device_channel_register() failed.
But after __dma_async_device_channel_register() failed, the caller will
goto err_out and freed the chan->local in the second time by free_percpu().
The cause of this problem is forget to set chan->local to NULL when
chan->local was freed in __dma_async_device_channel_register(). My
patch sets chan->local to NULL when the callee failed to avoid double free.
Fixes: d2fb0a0438384 ("dmaengine: break out channel registration")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
drivers/dma/dmaengine.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index fe6a460c4373..af3ee288bc11 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1086,6 +1086,7 @@ static int __dma_async_device_channel_register(struct dma_device *device,
kfree(chan->dev);
err_free_local:
free_percpu(chan->local);
+ chan->local = NULL;
return rc;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] dma: Fix a double free in dma_async_device_register
2021-03-31 1:44 [PATCH v2] dma: Fix a double free in dma_async_device_register Lv Yunlong
@ 2021-03-31 2:48 ` Dave Jiang
2021-04-12 9:36 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Dave Jiang @ 2021-03-31 2:48 UTC (permalink / raw)
To: Lv Yunlong, vkoul; +Cc: dmaengine, linux-kernel
On 3/30/2021 6:44 PM, Lv Yunlong wrote:
> In the first list_for_each_entry() macro of dma_async_device_register,
> it gets the chan from list and calls __dma_async_device_channel_register
> (..,chan). We can see that chan->local is allocated by alloc_percpu() and
> it is freed chan->local by free_percpu(chan->local) when
> __dma_async_device_channel_register() failed.
>
> But after __dma_async_device_channel_register() failed, the caller will
> goto err_out and freed the chan->local in the second time by free_percpu().
>
> The cause of this problem is forget to set chan->local to NULL when
> chan->local was freed in __dma_async_device_channel_register(). My
> patch sets chan->local to NULL when the callee failed to avoid double free.
>
> Fixes: d2fb0a0438384 ("dmaengine: break out channel registration")
> Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
> drivers/dma/dmaengine.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index fe6a460c4373..af3ee288bc11 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -1086,6 +1086,7 @@ static int __dma_async_device_channel_register(struct dma_device *device,
> kfree(chan->dev);
> err_free_local:
> free_percpu(chan->local);
> + chan->local = NULL;
> return rc;
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] dma: Fix a double free in dma_async_device_register
2021-03-31 1:44 [PATCH v2] dma: Fix a double free in dma_async_device_register Lv Yunlong
2021-03-31 2:48 ` Dave Jiang
@ 2021-04-12 9:36 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Vinod Koul @ 2021-04-12 9:36 UTC (permalink / raw)
To: Lv Yunlong; +Cc: dave.jiang, dmaengine, linux-kernel
On 30-03-21, 18:44, Lv Yunlong wrote:
> In the first list_for_each_entry() macro of dma_async_device_register,
> it gets the chan from list and calls __dma_async_device_channel_register
> (..,chan). We can see that chan->local is allocated by alloc_percpu() and
> it is freed chan->local by free_percpu(chan->local) when
> __dma_async_device_channel_register() failed.
>
> But after __dma_async_device_channel_register() failed, the caller will
> goto err_out and freed the chan->local in the second time by free_percpu().
>
> The cause of this problem is forget to set chan->local to NULL when
> chan->local was freed in __dma_async_device_channel_register(). My
> patch sets chan->local to NULL when the callee failed to avoid double free.
Applied after fixing subsystem name, thanks
--
~Vinod
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-04-12 9:52 UTC | newest]
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2021-03-31 2:48 ` Dave Jiang
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