From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Date: Wed, 11 Oct 2006 08:21:34 +0000 (-0700)
Subject: [PATCH] uml: make UML_SETJMP always safe
X-Git-Tag: v2.6.19-rc2~93
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b5cdb5797d364a112879e49cc708083853ffc592;p=linux-2.6

[PATCH] uml: make UML_SETJMP always safe

If enable is moved by GCC in a register its value may not be preserved after
coming back there with longjmp().  So, mark it as volatile to prevent this;
this is suggested (it seems) in info gcc, when it talks about -Wuninitialized.
 I re-read this and it seems to say something different, but I still believe
this may be needed.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/um/include/longjmp.h b/arch/um/include/longjmp.h
index e93c6d3e89..e860bc5848 100644
--- a/arch/um/include/longjmp.h
+++ b/arch/um/include/longjmp.h
@@ -12,7 +12,8 @@ extern void longjmp(jmp_buf, int);
 } while(0)
 
 #define UML_SETJMP(buf) ({ \
-	int n, enable;	   \
+	int n;	   \
+	volatile int enable;	\
 	enable = get_signals(); \
 	n = setjmp(*buf); \
 	if(n != 0) \