于 2012年12月06日 19:32, Oliver Neukum 写道: > 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.
thank you. (learned) :-) gchen. > > Regards > Oliver > > > -- Chen Gang Asianux Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
