[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>

2 files changed, 7 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);
diff --git a/arch/ia64/kernel/machine_kexec.c b/arch/ia64/kernel/machine_kexec.c
index e51cd904a23e..4f0f3b8c1ee2 100644
--- a/arch/ia64/kernel/machine_kexec.c
+++ b/arch/ia64/kernel/machine_kexec.c
@@ -82,6 +82,7 @@ static void ia64_machine_kexec(struct unw_frame_info *info, void *arg)
         unsigned long vector;
         int ii;
 
+        BUG_ON(!image);
         if (image->type == KEXEC_TYPE_CRASH) {
                 crash_save_this_cpu();
                 current->thread.ksp = (__u64)info->sw - 16;
@@ -120,6 +121,7 @@ static void ia64_machine_kexec(struct unw_frame_info *info, void *arg)
 
 void machine_kexec(struct kimage *image)
 {
+        BUG_ON(!image);
         unw_init_running(ia64_machine_kexec, image);
         for(;;);
 }