On Mon, 24 Nov 2014, Sebastian Andrzej Siewior wrote: > the following error pops up during "testusb -a -t 10" > | musb-hdrc musb-hdrc.1.auto: dma_pool_free buffer-128, > f134e000/be842000 (bad dma) > > hcd_buffer_create() creates a few buffers, the smallest has 32 bytes of > size. ARCH_KMALLOC_MINALIGN is set to 64 bytes. This combo results in > hcd_buffer_alloc() returning memory which is 32bytes aligned and it > might by identified by buffer_offset() as another buffer. This means the > buffer which is on a 32byte boundary will not get freed, instead it > tries to free another buffer with the error message. > > This patch fixes the issue by checking only if the lowest bit is set > which is the only "unaligned" offset which is currently passed to > usbtest_alloc_urb(). Another way of dealing with this would be to > respect ARCH_KMALLOC_MINALIGN in hcd_buffer_create() and having the > smallest buffer starting at 64 bytes in this case.
I think the second alternative would make more sense. It's pointless to have DMA buffers that aren't aligned strictly enough. Don't forget that other architectures can have other values for ARCH_KMALLOC_MINALIGN. The code should work on all architectures. Alan Stern -- 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
