[PATCH 1/2] w1 - fix fops in w1_bus_notify

[Hans-Frieder Vogt]

Introduce a check to make sure that fops are only called if they have been
defined by the slave module.
Without this check modules like w1_smem cause a NULL pointer
dereference bug.

Signed-off by: Hans-Frieder Vogt <hfvogt@xxxxxxx>
---
 drivers/w1/w1.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/w1/w1.c	2013-09-24 21:24:20.803261482 +0200
+++ b/drivers/w1/w1.c	2013-10-06 14:58:45.246528318 +0200
@@ -613,6 +613,9 @@ static int w1_bus_notify(struct notifier
 	sl = dev_to_w1_slave(dev);
 	fops = sl->family->fops;
 
+	if (!fops)
+		return 0;
+
 	switch (action) {
 	case BUS_NOTIFY_ADD_DEVICE:
 		/* if the family driver needs to initialize something... */

Hans-Frieder Vogt                       e-mail: hfvogt <at> gmx .dot. net

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