tree fb3744e543eb10d1ad7e750a08a4bc338cd297fc
parent 2395ecd98f028b16a6200eb81108a0f67461d16b
author Michael Holzheu <holzheu@linux.vnet.ibm.com> 1252657729 +0200
committer Martin Schwidefsky <schwidefsky@de.ibm.com> 1252657789 +0200

[S390] vmur: Invalid allocation sequence for vmur class

The vmur class is allocated after the CCW driver is registered
and it is destroyed before the CCW driver is unregistered.
This is not the correct sequence, because the vmur class can be used
via driver core callbacks that are triggered during the CCW driver
deregistration. For Example:

1. vmur device is online
2. vmur module is unloaded

This leads to the following function call stack:

    <4> [<0000000000387286>] device_destroy+0x36/0x5c
    <4> [<000003e000209714>] ur_set_offline_force+0x9c/0x10c [vmur]
    <4> [<000003e00020a928>] ur_remove+0x64/0xbc [vmur]
    <4> [<00000000003e4d2e>] ccw_device_remove+0x42/0x1ac
    <4> [<000000000038a1aa>] __device_release_driver+0x9a/0xe4
    <4> [<000000000038a2da>] driver_detach+0xe6/0xec
    <4> [<0000000000388ee4>] bus_remove_driver+0xc0/0x108
    <4> [<000003e00020ad5a>] ur_exit+0x52/0x84 [vmur]

In device_destroy() the vmur class is used. Since it is already freed,
this can lead to a kernel panic.

To fix the problem, the vmur class has to be allocated before the CCW
driver is registered and destroyed after the CCW driver has ben unregistered.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>