ipmi: make sure drivers were registered before unregistering them

The ipmi code will never register a PCI or Open Firmware driver if a
hardcoded device is provided by the user by providing device addresses via
the module parameters.  This can cause us to attempt to unregister a
driver that was never registered, resulting in an oops.  Keep track of
registration in order to avoid this.

Fixes a post-2.6.34 regression.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 4 deletions

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 35603dd4e6c5..311f85b67cc1 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -302,6 +302,12 @@ struct smi_info {
 
 static int force_kipmid[SI_MAX_PARMS];
 static int num_force_kipmid;
+#ifdef CONFIG_PCI
+static int pci_registered;
+#endif
+#ifdef CONFIG_PPC_OF
+static int of_registered;
+#endif
 
 static unsigned int kipmid_max_busy_us[SI_MAX_PARMS];
 static int num_max_busy_us;
@@ -3314,6 +3320,8 @@ static __devinit int init_ipmi_si(void)
         rv = pci_register_driver(&ipmi_pci_driver);
         if (rv)
                 printk(KERN_ERR PFX "Unable to register PCI driver: %d\n", rv);
+        else
+                pci_registered = 1;
 #endif
 
 #ifdef CONFIG_ACPI
@@ -3330,6 +3338,7 @@ static __devinit int init_ipmi_si(void)
 
 #ifdef CONFIG_PPC_OF
         of_register_platform_driver(&ipmi_of_platform_driver);
+        of_registered = 1;
 #endif
 
         /* We prefer devices with interrupts, but in the case of a machine
@@ -3383,11 +3392,13 @@ static __devinit int init_ipmi_si(void)
         if (unload_when_empty && list_empty(&smi_infos)) {
                 mutex_unlock(&smi_infos_lock);
 #ifdef CONFIG_PCI
-                pci_unregister_driver(&ipmi_pci_driver);
+                if (pci_registered)
+                        pci_unregister_driver(&ipmi_pci_driver);
 #endif
 
 #ifdef CONFIG_PPC_OF
-                of_unregister_platform_driver(&ipmi_of_platform_driver);
+                if (of_registered)
+                        of_unregister_platform_driver(&ipmi_of_platform_driver);
 #endif
                 driver_unregister(&ipmi_driver.driver);
                 printk(KERN_WARNING PFX
@@ -3478,14 +3489,16 @@ static __exit void cleanup_ipmi_si(void)
                 return;
 
 #ifdef CONFIG_PCI
-        pci_unregister_driver(&ipmi_pci_driver);
+        if (pci_registered)
+                pci_unregister_driver(&ipmi_pci_driver);
 #endif
 #ifdef CONFIG_ACPI
         pnp_unregister_driver(&ipmi_pnp_driver);
 #endif
 
 #ifdef CONFIG_PPC_OF
-        of_unregister_platform_driver(&ipmi_of_platform_driver);
+        if (of_registered)
+                of_unregister_platform_driver(&ipmi_of_platform_driver);
 #endif
 
         mutex_lock(&smi_infos_lock);