mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 17:59:32 +00:00
![Paul Mundt](/assets/img/avatar_default.png)
The dwarf unwinder ties in to an early initcall, but it's possible that return_address() calls will be made prior to that. This implements some additional error handling in to the dwarf unwinder as well as an exit path in the return_address() case to bail out if the unwinder hasn't come up yet. This fixes a NULL pointer deref in early boot when mempool_alloc() blows up on the not-yet-ready mempool via dwarf_unwind_stack(). Signed-off-by: Paul Mundt <lethal@linux-sh.org>
59 lines
1 KiB
C
59 lines
1 KiB
C
/*
|
|
* arch/sh/kernel/return_address.c
|
|
*
|
|
* Copyright (C) 2009 Matt Fleming
|
|
* Copyright (C) 2009 Paul Mundt
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <asm/dwarf.h>
|
|
|
|
#ifdef CONFIG_DWARF_UNWINDER
|
|
|
|
void *return_address(unsigned int depth)
|
|
{
|
|
struct dwarf_frame *frame;
|
|
unsigned long ra;
|
|
int i;
|
|
|
|
for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
|
|
struct dwarf_frame *tmp;
|
|
|
|
tmp = dwarf_unwind_stack(ra, frame);
|
|
if (!tmp)
|
|
return NULL;
|
|
|
|
if (frame)
|
|
dwarf_free_frame(frame);
|
|
|
|
frame = tmp;
|
|
|
|
if (!frame || !frame->return_addr)
|
|
break;
|
|
|
|
ra = frame->return_addr;
|
|
}
|
|
|
|
/* Failed to unwind the stack to the specified depth. */
|
|
WARN_ON(i != depth + 1);
|
|
|
|
if (frame)
|
|
dwarf_free_frame(frame);
|
|
|
|
return (void *)ra;
|
|
}
|
|
|
|
#else
|
|
|
|
void *return_address(unsigned int depth)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
#endif
|
|
|
|
EXPORT_SYMBOL_GPL(return_address);
|