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Commit 28b54990 authored by Anton Blanchard's avatar Anton Blanchard Committed by Benjamin Herrenschmidt
Browse files

powerpc: Check end of stack canary at oops time 



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: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent f89451fb

arch/powerpc/mm/fault.c

+6 −0
Original line number Diff line number Diff line
@@ -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 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, 
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, unsigned long address, int sig) 
	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);

}