[SCSI] sd: udev accessing an uninitialized scsi_disk field results in a crash

	sd_probe() calls class_device_add() even before initializing the
sdkp->device variable. class_device_add() eventually results in the user mode
udev program to be called. udev program can read the the allow_restart
attribute of the newly created scsi device. This is resulting in a crash as
the show function for allow_restart (i.e sd_show_allow_restart) returns the
attribute value by reading the sdkp->device->allow_restart variable. As the
sdkp->device is not initialized before calling the user mode hotplug helper,
this results in a crash.
	The patch below solves it by calling class_device_add() only after the
necessary fields in the scsi_disk structure are initialized properly.

Signed-off-by: Nagendra Singh Tomar <nagendra_tomar@adaptec.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 978bfc1e0c6a37c5edf91c916b783837a6ad4440..b781a90d6699038f4f2a0e819ca6d2a93dd619bb 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1647,16 +1647,6 @@ static int sd_probe(struct device *dev)
        if (error)
                goto out_put;
 
-       class_device_initialize(&sdkp->cdev);
-       sdkp->cdev.dev = &sdp->sdev_gendev;
-       sdkp->cdev.class = &sd_disk_class;
-       strncpy(sdkp->cdev.class_id, sdp->sdev_gendev.bus_id, BUS_ID_SIZE);
-
-       if (class_device_add(&sdkp->cdev))
-               goto out_put;
-
-       get_device(&sdp->sdev_gendev);
-
        sdkp->device = sdp;
        sdkp->driver = &sd_template;
        sdkp->disk = gd;
@@ -1670,6 +1660,16 @@ static int sd_probe(struct device *dev)
                        sdp->timeout = SD_MOD_TIMEOUT;
        }
 
+       class_device_initialize(&sdkp->cdev);
+       sdkp->cdev.dev = &sdp->sdev_gendev;
+       sdkp->cdev.class = &sd_disk_class;
+       strncpy(sdkp->cdev.class_id, sdp->sdev_gendev.bus_id, BUS_ID_SIZE);
+
+       if (class_device_add(&sdkp->cdev))
+               goto out_put;
+
+       get_device(&sdp->sdev_gendev);
+
        gd->major = sd_major((index & 0xf0) >> 4);
        gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
        gd->minors = 16;