V4L/DVB (8352): gspca: Buffers for USB exchanges cannot be in the stack.

gspca:    Protect dq_callback() against simultaneous USB exchanges.
          Temporary buffer for USB exchanges added in the device struct.
(all)     Use a temporary buffer for all USB exchanges.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c
index a566fd394895..242f0fb68d6e 100644
--- a/drivers/media/video/gspca/gspca.c
+++ b/drivers/media/video/gspca/gspca.c
@@ -1347,9 +1347,11 @@ ok:
                 gspca_dev->fr_i,
                 gspca_dev->fr_o);
 
-        if (gspca_dev->sd_desc->dq_callback)
+        if (gspca_dev->sd_desc->dq_callback) {
+                mutex_lock(&gspca_dev->usb_lock);
                 gspca_dev->sd_desc->dq_callback(gspca_dev);
-
+                mutex_unlock(&gspca_dev->usb_lock);
+        }
         return j;
 }