sony-laptop: fix early NULL pointer dereference

[Mattia Dongili <malattia@linux.it>]

Author: Mattia Dongili <malattia@linux.it>
Date:   Fri Apr 1 10:01:41 2011 +0900

    sony-laptop: fix early NULL pointer dereference
    
    The SNC acpi driver could get early notifications before it fully
    initializes and that could lead to dereferencing the sony_nc_handles
    structure pointer that is still NULL at that stage.
    Make sure we return early from the handle lookup function in these
    cases.
    
    Signed-off-by: Mattia Dongili <malattia@linux.it>
---

Hi Matthew,
if it's not too late, can you pick this one up instead of the previous
one (89ec2feafaedd759e53346d641f60863a14cfb9e)?
If it's too late I'll try and do a round of return value fixes later.

diff --git a/drivers/platform/x86/sony-laptop.c b/drivers/platform/x86/sony-laptop.c
index b2ce172..de79c18 100644
--- a/drivers/platform/x86/sony-laptop.c
+++ b/drivers/platform/x86/sony-laptop.c
@@ -810,6 +810,11 @@ static int sony_nc_handles_cleanup(struct platform_device *pd)
 static int sony_find_snc_handle(int handle)
 {
 	int i;
+
+	/* not initialized yet, return early */
+	if (!handles)
+		return -EINVAL;
+
 	for (i = 0; i < 0x10; i++) {
 		if (handles->cap[i] == handle) {
 			dprintk("found handle 0x%.4x (offset: 0x%.2x)\n",
-- 
mattia
:wq!