[I got no response after my corrected patch, so I try it again.
I request it to appear in -mm tree. Patch is against 2.6.20-rc6-mm3.]
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 <[email protected]>
---
arch/ia64/kernel/crash.c | 5 +++++
arch/ia64/kernel/machine_kexec.c | 2 ++
2 files changed, 7 insertions(+)
Index: b/arch/ia64/kernel/crash.c
===================================================================
--- a/arch/ia64/kernel/crash.c
+++ b/arch/ia64/kernel/crash.c
@@ -116,6 +116,11 @@ machine_crash_shutdown(struct pt_regs *p
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);
Index: b/arch/ia64/kernel/machine_kexec.c
===================================================================
--- a/arch/ia64/kernel/machine_kexec.c
+++ b/arch/ia64/kernel/machine_kexec.c
@@ -93,6 +93,7 @@ static void ia64_machine_kexec(struct un
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;
@@ -131,6 +132,7 @@ static void ia64_machine_kexec(struct un
void machine_kexec(struct kimage *image)
{
+ BUG_ON(!image);
unw_init_running(ia64_machine_kexec, image);
for(;;);
}