plip: fix parport_register_device name parameter

Plip passes a string "name" that is allocated on stack to
parport_register_device.  parport_register_device holds the pointer to
"name" and when the registering function exits, it points nowhere.

On some machine, this bug causes bad names to appear in /proc, such as
/proc/sys/dev/parport/parport0/devices/T^/�X^/�, on others, the plip
proc node is completely missing.

The patch also fixes documentation to note this requirement.

Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/parport-lowlevel.txt b/Documentation/parport-lowlevel.txt
index 265fcdcb8e5f..120eb20dbb09 100644
--- a/Documentation/parport-lowlevel.txt
+++ b/Documentation/parport-lowlevel.txt
@@ -339,6 +339,10 @@ Use this function to register your device driver on a parallel port
 ('port').  Once you have done that, you will be able to use
 parport_claim and parport_release in order to use the port.
 
+The ('name') argument is the name of the device that appears in /proc
+filesystem. The string must be valid for the whole lifetime of the
+device (until parport_unregister_device is called).
+
 This function will register three callbacks into your driver:
 'preempt', 'wakeup' and 'irq'.  Each of these may be NULL in order to
 indicate that you do not want a callback.