powerpc/eeh: Check handle_eeh_events() return value

Function eeh_event_handler() dereferences the pointer returned by
handle_eeh_events() without checking, causing a crash if NULL was
returned, which is expected in some situations.

This patch fixes this bug by checking for the value returned by
handle_eeh_events() before dereferencing it.

Signed-off-by: Kleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@vger.kernel.org [v3.4+]

diff --git a/arch/powerpc/platforms/pseries/eeh_event.c b/arch/powerpc/platforms/pseries/eeh_event.c
index 4cb375c0f8d173ff545c665971d8054d61fdfc17..fb506317ebb09141716d0d9bfe068fe7f953221d 100644 (file)
--- a/arch/powerpc/platforms/pseries/eeh_event.c
+++ b/arch/powerpc/platforms/pseries/eeh_event.c
@@ -85,8 +85,10 @@ static int eeh_event_handler(void * dummy)
        set_current_state(TASK_INTERRUPTIBLE);  /* Don't add to load average */
        edev = handle_eeh_events(event);
 
-       eeh_clear_slot(eeh_dev_to_of_node(edev), EEH_MODE_RECOVERING);
-       pci_dev_put(edev->pdev);
+       if (edev) {
+               eeh_clear_slot(eeh_dev_to_of_node(edev), EEH_MODE_RECOVERING);
+               pci_dev_put(edev->pdev);
+       }
 
        kfree(event);
        mutex_unlock(&eeh_event_mutex);