From: Jan Beulich <jbeulich@novell.com>
Date: Tue, 28 Nov 2006 19:12:59 +0000 (+0100)
Subject: [PATCH] x86-64: work around gcc4 issue with -Os in Dwarf2 stack unwind
X-Git-Tag: v2.6.19~7^2~3
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=ff0a538d8b08700df2b46f9aafc9fb2765071f0a;p=~shefty%2Frdma-dev.git

[PATCH] x86-64: work around gcc4 issue with -Os in Dwarf2 stack unwind

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>
---

diff --git a/kernel/unwind.c b/kernel/unwind.c
index f7e50d16dbf..ed0a21d4a90 100644
--- a/kernel/unwind.c
+++ b/kernel/unwind.c
@@ -938,8 +938,11 @@ int unwind(struct unwind_frame_info *frame)
 		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 *frame)
 	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