Add a check for the stack canary when we oops, similar to x86. This should make
it clear that we overran our stack:
Unable to handle kernel paging request for data at address 0x24652f63700ac689
Faulting instruction address: 0xc000000000063d24
Thread overran stack, or stack corrupted
Signed-off-by: Anton Blanchard <an...@samba.org>
---
Index: powerpc.git/arch/powerpc/mm/fault.c
===================================================================
--- powerpc.git.orig/arch/powerpc/mm/fault.c 2010-08-25 08:41:08.230086186
+1000
+++ powerpc.git/arch/powerpc/mm/fault.c 2010-08-25 09:12:38.276553103 +1000
@@ -30,6 +30,7 @@
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/perf_event.h>
+#include <linux/magic.h>
#include <asm/firmware.h>
#include <asm/page.h>
@@ -385,6 +386,7 @@ do_sigbus:
void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
{
const struct exception_table_entry *entry;
+ unsigned long *stackend;
/* Are we prepared to handle this fault? */
if ((entry = search_exception_tables(regs->nip)) != NULL) {
@@ -413,5 +415,9 @@ void bad_page_fault(struct pt_regs *regs
printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n",
regs->nip);
+ stackend = end_of_stack(current);
+ if (current != &init_task && *stackend != STACK_END_MAGIC)
+ printk(KERN_ALERT "Thread overran stack, or stack corrupted\n");
+
die("Kernel access of bad area", regs, sig);
}
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