1 files changed, 70 insertions, 21 deletions

diff --git a/arch/powerpc/platforms/pseries/eeh_driver.c b/arch/powerpc/platforms/pseries/eeh_driver.c
index 37c2cf743133..a3fefb61097c 100644
--- a/arch/powerpc/platforms/pseries/eeh_driver.c
+++ b/arch/powerpc/platforms/pseries/eeh_driver.c
@@ -25,6 +25,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
+#include <linux/module.h>
 #include <linux/pci.h>
 #include <asm/eeh.h>
 #include <asm/eeh_event.h>
@@ -47,6 +48,41 @@ static inline const char *eeh_pcid_name(struct pci_dev *pdev)
         return "";
 }
 
+/**
+ * eeh_pcid_get - Get the PCI device driver
+ * @pdev: PCI device
+ *
+ * The function is used to retrieve the PCI device driver for
+ * the indicated PCI device. Besides, we will increase the reference
+ * of the PCI device driver to prevent that being unloaded on
+ * the fly. Otherwise, kernel crash would be seen.
+ */
+static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev)
+{
+        if (!pdev || !pdev->driver)
+                return NULL;
+
+        if (!try_module_get(pdev->driver->driver.owner))
+                return NULL;
+
+        return pdev->driver;
+}
+
+/**
+ * eeh_pcid_put - Dereference on the PCI device driver
+ * @pdev: PCI device
+ *
+ * The function is called to do dereference on the PCI device
+ * driver of the indicated PCI device.
+ */
+static inline void eeh_pcid_put(struct pci_dev *pdev)
+{
+        if (!pdev || !pdev->driver)
+                return;
+
+        module_put(pdev->driver->driver.owner);
+}
+
 #if 0
 static void print_device_node_tree(struct pci_dn *pdn, int dent)
 {
@@ -128,23 +164,24 @@ static void *eeh_report_error(void *data, void *userdata)
         struct eeh_dev *edev = (struct eeh_dev *)data;
         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
         enum pci_ers_result rc, *res = userdata;
-        struct pci_driver *driver = dev->driver;
+        struct pci_driver *driver;
 
         /* We might not have the associated PCI device,
          * then we should continue for next one.
          */
         if (!dev) return NULL;
-
         dev->error_state = pci_channel_io_frozen;
 
-        if (!driver)
-                return NULL;
+        driver = eeh_pcid_get(dev);
+        if (!driver) return NULL;
 
         eeh_disable_irq(dev);
 
         if (!driver->err_handler ||
-            !driver->err_handler->error_detected)
+            !driver->err_handler->error_detected) {
+                eeh_pcid_put(dev);
                 return NULL;
+        }
 
         rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);
 
@@ -152,6 +189,7 @@ static void *eeh_report_error(void *data, void *userdata)
         if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
         if (*res == PCI_ERS_RESULT_NONE) *res = rc;
 
+        eeh_pcid_put(dev);
         return NULL;
 }
 
@@ -171,12 +209,14 @@ static void *eeh_report_mmio_enabled(void *data, void *userdata)
         enum pci_ers_result rc, *res = userdata;
         struct pci_driver *driver;
 
-        if (!dev) return NULL;
+        driver = eeh_pcid_get(dev);
+        if (!driver) return NULL;
 
-        if (!(driver = dev->driver) ||
-            !driver->err_handler ||
-            !driver->err_handler->mmio_enabled)
+        if (!driver->err_handler ||
+            !driver->err_handler->mmio_enabled) {
+                eeh_pcid_put(dev);
                 return NULL;
+        }
 
         rc = driver->err_handler->mmio_enabled(dev);
 
@@ -184,6 +224,7 @@ static void *eeh_report_mmio_enabled(void *data, void *userdata)
         if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
         if (*res == PCI_ERS_RESULT_NONE) *res = rc;
 
+        eeh_pcid_put(dev);
         return NULL;
 }
 
@@ -204,16 +245,19 @@ static void *eeh_report_reset(void *data, void *userdata)
         enum pci_ers_result rc, *res = userdata;
         struct pci_driver *driver;
 
-        if (!dev || !(driver = dev->driver))
-                return NULL;
-
+        if (!dev) return NULL;
         dev->error_state = pci_channel_io_normal;
 
+        driver = eeh_pcid_get(dev);
+        if (!driver) return NULL;
+
         eeh_enable_irq(dev);
 
         if (!driver->err_handler ||
-            !driver->err_handler->slot_reset)
+            !driver->err_handler->slot_reset) {
+                eeh_pcid_put(dev);
                 return NULL;
+        }
 
         rc = driver->err_handler->slot_reset(dev);
         if ((*res == PCI_ERS_RESULT_NONE) ||
@@ -221,6 +265,7 @@ static void *eeh_report_reset(void *data, void *userdata)
         if (*res == PCI_ERS_RESULT_DISCONNECT &&
              rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
 
+        eeh_pcid_put(dev);
         return NULL;
 }
 
@@ -240,20 +285,22 @@ static void *eeh_report_resume(void *data, void *userdata)
         struct pci_driver *driver;
 
         if (!dev) return NULL;
-
         dev->error_state = pci_channel_io_normal;
 
-        if (!(driver = dev->driver))
-                return NULL;
+        driver = eeh_pcid_get(dev);
+        if (!driver) return NULL;
 
         eeh_enable_irq(dev);
 
         if (!driver->err_handler ||
-            !driver->err_handler->resume)
+            !driver->err_handler->resume) {
+                eeh_pcid_put(dev);
                 return NULL;
+        }
 
         driver->err_handler->resume(dev);
 
+        eeh_pcid_put(dev);
         return NULL;
 }
 
@@ -272,20 +319,22 @@ static void *eeh_report_failure(void *data, void *userdata)
         struct pci_driver *driver;
 
         if (!dev) return NULL;
-
         dev->error_state = pci_channel_io_perm_failure;
 
-        if (!(driver = dev->driver))
-                return NULL;
+        driver = eeh_pcid_get(dev);
+        if (!driver) return NULL;
 
         eeh_disable_irq(dev);
 
         if (!driver->err_handler ||
-            !driver->err_handler->error_detected)
+            !driver->err_handler->error_detected) {
+                eeh_pcid_put(dev);
                 return NULL;
+        }
 
         driver->err_handler->error_detected(dev, pci_channel_io_perm_failure);
 
+        eeh_pcid_put(dev);
         return NULL;
 }