Hi Geert-san again, > Hi Geert-san, > > Thank you for the reply again! > > > Hi Shimoda-san, > > > > On Mon, Feb 16, 2015 at 2:52 AM, Yoshihiro Shimoda > > <yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote: > > > According to the gadget.h, a "complete" function will always be called > > > with interrupts disabled. However, sometimes usbhsg_queue_pop() function > > > is called with interrupts enabled. So, this function should calls > > > local_irq_save() before this calls the usb_gadget_giveback_request(). > > > Otherwise, there is possible to cause a spinlock suspected in a gadget > > > complete function. > > > > I still feel uneasy about adding the call to local_irq_save(), as the need for > > this is usually an indicator of another locking problem. > > I also think that I would like to avoid using local_irq_save(). > But, I have no idea to resolve this issue for now. After I modified usb-dmac driver to use a tasklet instead of a kthread, this issue disappeared. My understanding is the followings: - According to the backtrace below, during usbhsf_dma_complete() was running, a softirq happened. After ncm_tx_tasklet() was called, the issue happened. http://thread.gmane.org/gmane.linux.usb.general/122023/focus=43729 - This means that usbhsf_dma_complete() ran on a kthread. So, ncm driver is able to do the ncm_tx_tasklet(). - After the current usb-dmac driver, since usbhsf_dma_complete() runs on a tasklet, ncm driver is not able to do the ncm_tx_tasklet during usbhsf_dma_complete() was running. So, I would like to recall this patch and I will resubmit this patch series as v3. Best regards, Yoshihiro Shimoda ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
