Re: [PATCH] mmc: warn for invalid SDIO data buffers【请注意，邮件由linux-mmc-owner@xxxxxxxxxxxxxxx代发】

[Shawn Lin]

Hi Arnd

On 2021/6/30 20:20, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> Jernej Skrabec reported a problem with the cw1200 driver failing on
> arm64 systems with CONFIG_VMAP_STACK=y.
>
> The driver in this case passes a pointer to a stack variable (in vmalloc
> space) into the sdio layer, which gets translated into an invalid DMA
> address.
>
> Even without CONFIG_VMAP_STACK, the driver is still unreliable, as
> cache invalidations on the DMA buffer may cause random data corruption
> in adjacent stack slots.
>
> This could be worked around in the SDIO core, but in the discussion we
> decided that passing a stack variable into SDIO should always be considered
> a bug, as it is for USB drivers.
>
> Change the sdio core to produce a one-time warning for any on-stack
> (both with and without CONFIG_VMAP_STACK) as well as any vmalloc
> or module-local address that would have the same translation problem.

This was the previous comment about the same topic.
Should we check for mmc_io_rw_direct?

https://www.spinics.net/lists/linux-mmc/msg41794.html

> Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
> Link: https://lore.kernel.org/lkml/20210622202345.795578-1-jernej.skrabec@xxxxxxxxx/
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
>   drivers/mmc/core/sdio_ops.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/mmc/core/sdio_ops.c b/drivers/mmc/core/sdio_ops.c
> index 4c229dd2b6e5..14e983faf223 100644
> --- a/drivers/mmc/core/sdio_ops.c
> +++ b/drivers/mmc/core/sdio_ops.c
> @@ -6,6 +6,7 @@
>    */
>   
>   #include <linux/scatterlist.h>
> +#include <linux/sched/task_stack.h>
>   
>   #include <linux/mmc/host.h>
>   #include <linux/mmc/card.h>
> @@ -124,6 +125,7 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
>   	int err;
>   
>   	WARN_ON(blksz == 0);
> +	WARN_ON_ONCE(is_vmalloc_or_module_addr(buf) || object_is_on_stack(buf));
>   
>   	/* sanity check */
>   	if (addr & ~0x1FFFF)