On Thursday 06 December 2012 18:51:25 Chen Gang wrote:
> Hello Greg Kroah-Hartman:
>
> in drivers/usb/core/message.c:
> at line 943, status is kmalloc ( sizeof u16 )
> at line 952, assign the value of status to data
> at line 953, free status.
>
> it is better to let "u16 status" instead of "u16 *status = kmalloc...".
No, that would be a bug, because then we would do DMA on the stack.
Doing DMA on the stack violates the DMA rules. Anything passed to
usb_control_msg() as a buffer must be allocated from the heap,
regardless of size.
Regards
Oliver
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