2008-02-19 14:49:41

by Martin Schwidefsky

[permalink] [raw]
Subject: [patch 12/13] Fix futex_atomic_cmpxchg_std inline assembly.

From: Heiko Carstens <[email protected]>

Add missing exception table entry so that the kernel can handle
proctection exceptions as well on the cs instruction. Currently only
specification exceptions are handled correctly.
The missing entry allows user space to crash the kernel.

Cc: stable <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---

arch/s390/lib/uaccess_std.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

Index: quilt-2.6/arch/s390/lib/uaccess_std.c
===================================================================
--- quilt-2.6.orig/arch/s390/lib/uaccess_std.c
+++ quilt-2.6/arch/s390/lib/uaccess_std.c
@@ -293,10 +293,10 @@ int futex_atomic_cmpxchg_std(int __user

asm volatile(
" sacf 256\n"
- " cs %1,%4,0(%5)\n"
- "0: lr %0,%1\n"
- "1: sacf 0\n"
- EX_TABLE(0b,1b)
+ "0: cs %1,%4,0(%5)\n"
+ "1: lr %0,%1\n"
+ "2: sacf 0\n"
+ EX_TABLE(0b,2b) EX_TABLE(1b,2b)
: "=d" (ret), "+d" (oldval), "=m" (*uaddr)
: "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
: "cc", "memory" );

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.