[PATCH] work around gcc4 issue with -Os in Dwarf2 stack unwind code

Jan Beulich
2006-11-28T14:10:57Z

This fixes a problem with gcc4 mis-compiling the stack unwind code under
-Os, which resulted in 'stuck' messages whenever an assembly routine was
encountered.

(The second hunk is trivial cleanup.)

Signed-off-by: Jan Beulich <jbeulich@novell.com>

--- linux-2.6.19-rc6/kernel/unwind.c 2006-11-22 14:54:10.000000000 +0100
+++ 2.6.19-rc6-unwind-stuck/kernel/unwind.c 2006-11-28 15:02:15.000000000 +0100
@@ -938,8 +938,11 @@ int unwind(struct unwind_frame_info *fra
else {
retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end);
/* skip augmentation */
- if (((const char *)(cie + 2))[1] == 'z')
- ptr += get_uleb128(&ptr, end);
+ if (((const char *)(cie + 2))[1] == 'z') {
+ uleb128_t augSize = get_uleb128(&ptr, end);
+
+ ptr += augSize;
+ }
if (ptr > end
|| retAddrReg >= ARRAY_SIZE(reg_info)
|| REG_INVALID(retAddrReg)
@@ -963,9 +966,7 @@ int unwind(struct unwind_frame_info *fra
if (cie == NULL || fde == NULL) {
#ifdef CONFIG_FRAME_POINTER
unsigned long top, bottom;
-#endif

-#ifdef CONFIG_FRAME_POINTER
top = STACK_TOP(frame->task);
bottom = STACK_BOTTOM(frame->task);
# if FRAME_RETADDR_OFFSET < 0