In the Linux kernel, the following vulnerability has been resolved:

ASoC: stm32: spdifrx: fix dma channel release in stm32_spdifrx_remove

In case of error when requesting ctrl_chan DMA channel, ctrl_chan is not
null. So the release of the dma channel leads to the following issue:
[    4.879000] st,stm32-spdifrx 500d0000.audio-controller:
dma_request_slave_channel error -19
[    4.888975] Unable to handle kernel NULL pointer dereference
at virtual address 000000000000003d
[...]
[    5.096577] Call trace:
[    5.099099]  dma_release_channel+0x24/0x100
[    5.103235]  stm32_spdifrx_remove+0x24/0x60 [snd_soc_stm32_spdifrx]
[    5.109494]  stm32_spdifrx_probe+0x320/0x4c4 [snd_soc_stm32_spdifrx]

To avoid this issue, release channel only if the pointer is valid.

kernel.org https://git.kernel.org/stable/c/0d75f887aabd80cf37ea48d28f159afa7850ea28 [No types assigned]

kernel.org https://git.kernel.org/stable/c/22ae9321054cf7f36c537702af133659f51a0b88 [No types assigned]

kernel.org https://git.kernel.org/stable/c/23bdbd1ef3e063e03d3c50c15a591b005ebbae39 [No types assigned]

kernel.org https://git.kernel.org/stable/c/3a977b554f668382dfba31fd62e4cce4fe5643db [No types assigned]

kernel.org https://git.kernel.org/stable/c/4f1d74f74752eab8af6b8b28797dc6490d57374c [No types assigned]

kernel.org https://git.kernel.org/stable/c/9bb4af400c386374ab1047df44c508512c08c31f [No types assigned]