On 11/25/2014 12:54 PM, Sergei Shtylyov wrote:
> Hello.
Hi Sergei,
> On 11/24/2014 11:54 PM, 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 creating the smallest DMA buffer with the
>> size of ARCH_KMALLOC_MINALIGN. This will be either 32 or 64 bytes. If the
>> ARCH_KMALLOC_MINALIGN is 128 (currently powerpc64, mips ip32, x86 pentium
>> 4) then it will create the first buffer with 128 bytes and will have
>> only 3
>> buffers in total. There is a BUILD_BUG_ON() now in case someone has a
>> ARCH_KMALLOC_MINALIGN greater than 256 bytes.
>
> Reading the patch, the actual limit seems to be 128 instead.
if ARCH_KMALLOC_MINALIGN is greater than 64. What did I wrong?
>
>> Cc: stable@xxxxxxxxxxxxxxx
>> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
>> ---
>> drivers/usb/core/buffer.c | 5 +++++
>> include/linux/usb/hcd.h | 8 ++++++--
>> 2 files changed, 11 insertions(+), 2 deletions(-)
>
>> diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
>> index 684ef70dc09d..a80d1ec8b1b0 100644
>> --- a/drivers/usb/core/buffer.c
>> +++ b/drivers/usb/core/buffer.c
> [...]
>> @@ -58,6 +62,7 @@ int hcd_buffer_create(struct usb_hcd *hcd)
>> !(hcd->driver->flags & HCD_LOCAL_MEM))
>> return 0;
>>
>> + BUILD_BUG_ON(ARCH_KMALLOC_MINALIGN > 128);
>> for (i = 0; i < HCD_BUFFER_POOLS; i++) {
>> size = pool_max[i];
>> if (!size)
> [...]
>
> WBR, Sergei
>
Sebastian
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