Re: [PATCH v2] dma: Fix a double free in dma_async_device_register

From: Vinod Koul
Date: Mon Apr 12 2021 - 05:52:33 EST


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