USB: option: fix usage of urb->status abuse

Might fix bug 8561

On Mon, 4 Jun 2007, Paulo Pereira wrote:

> The patch that you send is not resolving the problem... :(
> I stil have Kernel panic after 45/60 min of work with Ktorrent/Amule...
>
> The Drump is:
>
> Call Trace:
> [<c055fb36>] usb_hcd_submit+0xb1/0x763
> [<f9276488>] ipt_do_table+0x2c7/0x2ef [ip_tables]
> [<f929a6d7>] nf_ct_deliver_cached_events+0x41/0x96 [nf_conntrak]
> [<f9288254>] ipv4_confirm+0x36/0c3b [nf_conntrack_ipv4]
> [<c05ce7c2>] tcp_v4_rcv+0x827/0x899
> [<c05afcc0>] nf_hook_slow+0x4d/0xb5
> [<c042826f>] irq_enter+0x19/0x23
> [<c042826f>] irq_enter+0x19/0x23
> [<c040794c>] do_IRQ+0xbd/0xd1
> [<f90893c9>] option_write+0xa7/0xef [option]

Okay, from this it looks like there's a problem in the option.c serial
driver.  Glancing at the code, it's obvious why: The thing totally
abuses the USB API.

Try applying this patch; it should help.

From: Alan Stern <stern@rowland.harvard.edu>
Cc: Paulo Pereira <pfmp.404@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 17 insertions, 3 deletions

diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 5d3999e3ff61..b37d65fc8752 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -38,6 +38,7 @@
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <linux/module.h>
+#include <linux/bitops.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 
@@ -240,6 +241,7 @@ struct option_port_private {
         /* Output endpoints and buffer for this port */
         struct urb *out_urbs[N_OUT_URB];
         char out_buffer[N_OUT_URB][OUT_BUFLEN];
+        unsigned long out_busy;         /* Bit vector of URBs in use */
 
         /* Settings for the port */
         int rts_state;  /* Handshaking pins (outputs) */
@@ -370,7 +372,7 @@ static int option_write(struct usb_serial_port *port,
                         todo = OUT_BUFLEN;
 
                 this_urb = portdata->out_urbs[i];
-                if (this_urb->status == -EINPROGRESS) {
+                if (test_and_set_bit(i, &portdata->out_busy)) {
                         if (time_before(jiffies,
                                         portdata->tx_start_time[i] + 10 * HZ))
                                 continue;
@@ -394,6 +396,7 @@ static int option_write(struct usb_serial_port *port,
                         dbg("usb_submit_urb %p (write bulk) failed "
                                 "(%d, has %d)", this_urb,
                                 err, this_urb->status);
+                        clear_bit(i, &portdata->out_busy);
                         continue;
                 }
                 portdata->tx_start_time[i] = jiffies;
@@ -446,12 +449,23 @@ static void option_indat_callback(struct urb *urb)
 static void option_outdat_callback(struct urb *urb)
 {
         struct usb_serial_port *port;
+        struct option_port_private *portdata;
+        int i;
 
         dbg("%s", __FUNCTION__);
 
         port = (struct usb_serial_port *) urb->context;
 
         usb_serial_port_softint(port);
+
+        portdata = usb_get_serial_port_data(port);
+        for (i = 0; i < N_OUT_URB; ++i) {
+                if (portdata->out_urbs[i] == urb) {
+                        smp_mb__before_clear_bit();
+                        clear_bit(i, &portdata->out_busy);
+                        break;
+                }
+        }
 }
 
 static void option_instat_callback(struct urb *urb)
@@ -518,7 +532,7 @@ static int option_write_room(struct usb_serial_port *port)
 
         for (i=0; i < N_OUT_URB; i++) {
                 this_urb = portdata->out_urbs[i];
-                if (this_urb && this_urb->status != -EINPROGRESS)
+                if (this_urb && !test_bit(i, &portdata->out_busy))
                         data_len += OUT_BUFLEN;
         }
 
@@ -537,7 +551,7 @@ static int option_chars_in_buffer(struct usb_serial_port *port)
 
         for (i=0; i < N_OUT_URB; i++) {
                 this_urb = portdata->out_urbs[i];
-                if (this_urb && this_urb->status == -EINPROGRESS)
+                if (this_urb && test_bit(i, &portdata->out_busy))
                         data_len += this_urb->transfer_buffer_length;
         }
         dbg("%s: %d", __FUNCTION__, data_len);