In the seq_file 'show' handler for "/proc/comedi" - `comedi_read()` in
"comedi/proc.c", call `comedi_dev_get_from_minor()` instead of
`comedi_dev_from_minor()` to increment the reference counter for the
`struct comedi_device` while it is being examined. Call
`comedi_dev_put()` to decrement the reference afterwards. Also acquire
the `attach_lock` rwsem while checking whether the device is attached.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/proc.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/comedi/proc.c b/drivers/staging/comedi/proc.c
index ade0003..da6bc58 100644
--- a/drivers/staging/comedi/proc.c
+++ b/drivers/staging/comedi/proc.c
@@ -41,16 +41,20 @@ static int comedi_read(struct seq_file *m, void *v)
"driver_name, board_name, n_subdevices");
for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
- struct comedi_device *dev = comedi_dev_from_minor(i);
+ struct comedi_device *dev = comedi_dev_get_from_minor(i);
+
if (!dev)
continue;
+ down_read(&dev->attach_lock);
if (dev->attached) {
devices_q = 1;
seq_printf(m, "%2d: %-20s %-20s %4d\n",
i, dev->driver->driver_name,
dev->board_name, dev->n_subdevices);
}
+ up_read(&dev->attach_lock);
+ comedi_dev_put(dev);
}
if (!devices_q)
seq_puts(m, "no devices\n");
--
1.8.4.2
_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
