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Commit 66fa9b10 authored by Keith Owens's avatar Keith Owens Committed by Tony Luck
Browse files

[IA64] Correct unwind validation code 



Both rp_loc and pfs_loc can be in the register stack area _or_ they can
be in the memory stack area, the latter occurs when a struct pt_regs is
pushed.  Correct the validation check on these fields to check for both
stack areas.  Not allowing for memory stack locations means no
backtrace past ia64_leave_kernel, or any other code that uses
PT_REGS_UNWIND_INFO.

Signed-off-by: default avatarKeith Owens <kaos@sgi.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 9be26f4c

arch/ia64/kernel/unwind.c

+11 −5
Original line number Diff line number Diff line
@@ -1856,11 +1856,19 @@ find_save_locs (struct unw_frame_info *info) 
	return 0;

}



static int

unw_valid(const struct unw_frame_info *info, unsigned long* p)

{

	unsigned long loc = (unsigned long)p;

	return (loc >= info->regstk.limit && loc < info->regstk.top) ||

	       (loc >= info->memstk.top && loc < info->memstk.limit);

}



int

unw_unwind (struct unw_frame_info *info)

{

	unsigned long prev_ip, prev_sp, prev_bsp;

	unsigned long ip, pr, num_regs, rp_loc, pfs_loc;

	unsigned long ip, pr, num_regs;

	STAT(unsigned long start, flags;)

	int retval;
@@ -1871,8 +1879,7 @@ unw_unwind (struct unw_frame_info *info) 
	prev_bsp = info->bsp;



	/* validate the return IP pointer */

	rp_loc = (unsigned long) info->rp_loc;

	if ((rp_loc < info->regstk.limit) || (rp_loc > info->regstk.top)) {

	if (!unw_valid(info, info->rp_loc)) {

		/* FIXME: should really be level 0 but it occurs too often. KAO */

		UNW_DPRINT(1, "unwind.%s: failed to locate return link (ip=0x%lx)!\n",

			   __FUNCTION__, info->ip);
@@ -1888,8 +1895,7 @@ unw_unwind (struct unw_frame_info *info) 
	}



	/* validate the previous stack frame pointer */

	pfs_loc = (unsigned long) info->pfs_loc;

	if ((pfs_loc < info->regstk.limit) || (pfs_loc > info->regstk.top)) {

	if (!unw_valid(info, info->pfs_loc)) {

		UNW_DPRINT(0, "unwind.%s: failed to locate ar.pfs!\n", __FUNCTION__);

		STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));

		return -1;