[IA64] Fix NULL-pointer dereference in ia64_machine_kexec()

This patch fixes a NULL-pointer dereference in ia64_machine_kexec().

The variable ia64_kimage is set in machine_kexec_prepare() which is
called from sys_kexec_load(). If kdump wasn't configured before,
ia64_kimage is NULL.  machine_kdump_on_init() passes ia64_kimage() to
machine_kexec() which assumes a valid value.

The patch also adds a few sanity checks for the image to simplify
debugging of similar problems in future.

Signed-off-by: Bernhard Walle <bwalle@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/ia64/kernel/crash.c b/arch/ia64/kernel/crash.c
index 2018e624f5e2..9d92097ce96d 100644
--- a/arch/ia64/kernel/crash.c
+++ b/arch/ia64/kernel/crash.c
@@ -118,6 +118,11 @@ machine_crash_shutdown(struct pt_regs *pt)
 static void
 machine_kdump_on_init(void)
 {
+        if (!ia64_kimage) {
+                printk(KERN_NOTICE "machine_kdump_on_init(): "
+                                "kdump not configured\n");
+                return;
+        }
         local_irq_disable();
         kexec_disable_iosapic();
         machine_kexec(ia64_kimage);