st: fix potential null pointer dereference.
If cdev_add() returns an error, the code calls
cdev_del() passing the STm->cdevs[rew] pointer as parameter;
the problem is that the pointer has not been initialized yet.
This patch fixes the problem by moving the STm->cdevs[rew] pointer
initialization before the call to cdev_add().
It also sets STm->devs[rew] and STm->cdevs[rew] to NULL in
case of failure.
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index b37b9b0..3e79c80 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4083,6 +4083,7 @@
}
cdev->owner = THIS_MODULE;
cdev->ops = &st_fops;
+ STm->cdevs[rew] = cdev;
error = cdev_add(cdev, cdev_devno, 1);
if (error) {
@@ -4091,7 +4092,6 @@
pr_err("st%d: Device not attached.\n", dev_num);
goto out_free;
}
- STm->cdevs[rew] = cdev;
i = mode << (4 - ST_NBR_MODE_BITS);
snprintf(name, 10, "%s%s%s", rew ? "n" : "",
@@ -4110,8 +4110,9 @@
return 0;
out_free:
cdev_del(STm->cdevs[rew]);
- STm->cdevs[rew] = NULL;
out:
+ STm->cdevs[rew] = NULL;
+ STm->devs[rew] = NULL;
return error;
}