[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: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/kernel/unwind.c b/arch/ia64/kernel/unwind.c
index b0b08b5f3eca217ccecaced1d0188a66b98fd879..c1bdb5131814c8f9f24e01cc51eae54e4df35666 100644 (file)
--- a/arch/ia64/kernel/unwind.c
+++ b/arch/ia64/kernel/unwind.c
@@ -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;