Hello Max, Max Vozeler wrote: > Hi NÃmeth, > > On 17.12.2010 06:45, NÃmeth MÃrton wrote: >>>> NÃmeth MÃrton wrote: >>>>> I'm working with usbip and I sometimes see a stall when I run >>>>> the "lsusb" command from the userspace. >>> Does it eventually recover? >> No, it doesn't. After 120 seconds messages are printed in dmesg >> that the "lsusb" process is blocked more than 120 seconds. > > Can you describe the sequence of events which > happened before the hang? Boot EeePC 901. Attach hama AC-150 webcam. Execute the following commands as root: echo 0 >/sys/devices/platform/eeepc/camera insmod /usr/src/linux/drivers/staging/usbip/usbip_common_mod.ko insmod /usr/src/linux/drivers/staging/usbip/usbip.ko usbip_bind_driver --list usbip_bind_driver --usbip 3-2 usbipd On a second xterm window execute the following commands: insmod /usr/src/linux/drivers/staging/usbip/vhci-hcd.ko lsusb usbip --list localhost usbip -a localhost 3-2 usbip -p strace lsusb Note that the hama AC-150 webcam has a snapshot button on it which uses the interrupt endpoint. The interrupt URB is sent in when the gspca_sonixj driver activates in order to catch the button events. The hang maybe related, I don't know. > > Was the device detached before or during lsusb? > > Perhaps try echo t > /proc/sysrq-trigger to see > where exactly lsusb gets stuck. > > I found processes can get stuck in usb_kill_urb > if they tried to unlink an URB, but the unlink > request was not answered before detach. > > Perhaps this is related. I am attaching a patch > which fixes that bug for me, perhaps you could > try if it makes a difference? I'll try your patch later, thanks. > >>>>> I added some debug messages >>>>> and it seems that the kernel_recvmsg() in >>>>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=drivers/staging/usbip/usbip_common.c;h=210ef16bab8d271a52e5d36cd1994aad57ad99e1;hb=HEAD >>>>> >>>>> This is the only place I could find where the TCP messages are arriving in >>>>> the usbip code. >>>>> >>>>> What happens if a message does not arrive? Does it stall forever? >>> Yes, it will block until detached or until a TCP >>> timeout or error closes the connection. >>> >>> The TCP timeout can take several minutes. >> What I don't really understand is that how is it possible that >> a packet from TCP communication is lost? TCP resends the lost >> packets automatically. In my case I run both the usbip server >> and client on the same machine using the host name "localhost". >> So I assume that there might be a protocol handshake problem >> here. > > Agreed, it doesn't seem like a TCP error is > causing the hang in this case. > > Max > > _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
