| Message ID | 20240614224556.23215-1-d.smirnov@inbox.lv (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [V4] usb: serial: Fix mos7840 hangup on resume | expand |
Are any further steps required on my part? --- Dmitry
On Sat, Jun 15, 2024 at 01:45:56AM +0300, Dmitry Smirnov wrote: > This patch addresses a kernel hang issue with the mos7840 driver when > PC resuming from a suspend with a device connected to the serial port. > > This patch introduces two new functions: mos7840_suspend() and mos7840_resume(). > > Tested with Delock 87414 USB 2.0 to 4x serial adapter. > > Signed-off-by: Dmitry Smirnov <d.smirnov@inbox.lv> > --- > V4: Removed debug prints > V3: Code cleanup > V2: Reworked mos7840_suspend() based on comments from reviewer > V1: Initial version Thanks for the fix and sorry about the late reply on this one. I took a closer look at this today, and indeed we have a kernel crash here on resume with mos7840. This is a bug that dates back to 2011 when I added support for multiple read URBs and failed to notice this interaction with drivers that only uses one URB. This actually affects a few more drivers, but judging from a quick look not as severely as for mos7840 which uses a different structure for the URB context. I'll make sure to go back and review this more thoroughly in the next few weeks. > +static int mos7840_resume(struct usb_serial *serial) > +{ > + struct moschip_port *mos7840_port; > + struct usb_serial_port *port; > + int res; > + int i; > + > + for (i = 0; i < serial->num_ports; ++i) { > + port = serial->port[i]; > + if (!tty_port_initialized(&port->port)) > + continue; > + > + mos7840_port = usb_get_serial_port_data(port); > + > + if (port->bulk_in_size) { Not needed, checked on probe. Need to set the read_urb_busy flag here. > + res = usb_submit_urb(mos7840_port->read_urb, GFP_NOIO); > + if (res) { > + usb_kill_urb(mos7840_port->read_urb); Not needed as submission failed. > + mos7840_port->read_urb_busy = false; > + } > + } > + } > + > + return 0; > +} I've reworded the commit message to provide some more background on the crash, added the missing busy flag set, dropped the unnecessary bulk_in_size check and dropped the unnecessary usb_kill_urb() in case submission fails on resume. The end result is here: https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial.git/commit/?h=usb-linus&id=c15a688e49987385baa8804bf65d570e362f8576 Johan
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c index 8b0308d84270..2f4b2c8f4a48 100644 --- a/drivers/usb/serial/mos7840.c +++ b/drivers/usb/serial/mos7840.c @@ -1737,6 +1737,52 @@ static void mos7840_port_remove(struct usb_serial_port *port) kfree(mos7840_port); } +static int mos7840_suspend(struct usb_serial *serial, pm_message_t message) +{ + struct moschip_port *mos7840_port; + struct usb_serial_port *port; + int i; + + for (i = 0; i < serial->num_ports; ++i) { + port = serial->port[i]; + if (!tty_port_initialized(&port->port)) + continue; + + mos7840_port = usb_get_serial_port_data(port); + + usb_kill_urb(mos7840_port->read_urb); + mos7840_port->read_urb_busy = false; + } + + return 0; +} + +static int mos7840_resume(struct usb_serial *serial) +{ + struct moschip_port *mos7840_port; + struct usb_serial_port *port; + int res; + int i; + + for (i = 0; i < serial->num_ports; ++i) { + port = serial->port[i]; + if (!tty_port_initialized(&port->port)) + continue; + + mos7840_port = usb_get_serial_port_data(port); + + if (port->bulk_in_size) { + res = usb_submit_urb(mos7840_port->read_urb, GFP_NOIO); + if (res) { + usb_kill_urb(mos7840_port->read_urb); + mos7840_port->read_urb_busy = false; + } + } + } + + return 0; +} + static struct usb_serial_driver moschip7840_4port_device = { .driver = { .owner = THIS_MODULE, @@ -1764,6 +1810,8 @@ static struct usb_serial_driver moschip7840_4port_device = { .port_probe = mos7840_port_probe, .port_remove = mos7840_port_remove, .read_bulk_callback = mos7840_bulk_in_callback, + .suspend = mos7840_suspend, + .resume = mos7840_resume, }; static struct usb_serial_driver * const serial_drivers[] = {
This patch addresses a kernel hang issue with the mos7840 driver when PC resuming from a suspend with a device connected to the serial port. This patch introduces two new functions: mos7840_suspend() and mos7840_resume(). Tested with Delock 87414 USB 2.0 to 4x serial adapter. Signed-off-by: Dmitry Smirnov <d.smirnov@inbox.lv> --- V4: Removed debug prints V3: Code cleanup V2: Reworked mos7840_suspend() based on comments from reviewer V1: Initial version drivers/usb/serial/mos7840.c | 48 ++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) base-commit: c3f38fa61af77b49866b006939479069cd451173