ACPI: thinkpad-acpi: fix oops when a module parameter has no value

set_ibm_param() could OOPS with a NULL pointer derreference if one did not give
any values for a module parameter it handles.  This would, of course, cause all
sort of trouble for future modprobing and require a reboot to clean up
properly.

Fix it by returning -EINVAL if no values are given for the parameter, and also
avoid any nastyness from BUG_ON while at it.

How to reproduce: modprobe thinkpad-acpi brightness

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Tested-by: Mike Kershaw <dragorn@kismetwireless.net>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 8c943077528538ce1b77e0f44ac7c3d02eb34cbd..ab23a3221585302fec8a33d79ceade142b93f7dc 100644 (file)
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -4817,9 +4817,15 @@ static int __init set_ibm_param(const char *val, struct kernel_param *kp)
        unsigned int i;
        struct ibm_struct *ibm;
 
+       if (!kp || !kp->name || !val)
+               return -EINVAL;
+
        for (i = 0; i < ARRAY_SIZE(ibms_init); i++) {
                ibm = ibms_init[i].data;
-               BUG_ON(ibm == NULL);
+               WARN_ON(ibm == NULL);
+
+               if (!ibm || !ibm->name)
+                       continue;
 
                if (strcmp(ibm->name, kp->name) == 0 && ibm->write) {
                        if (strlen(val) > sizeof(ibms_init[i].param) - 2)