[PATCH] x86_64: Fix 32bit thread coredumps

When a register set is passed in don't try to fix up the pointer.

Noticed by Al Viro

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/ia32/ia32_binfmt.c b/arch/x86_64/ia32/ia32_binfmt.c
index 830feb2..2b760d0 100644
--- a/arch/x86_64/ia32/ia32_binfmt.c
+++ b/arch/x86_64/ia32/ia32_binfmt.c
@@ -217,8 +217,7 @@
 	if (!tsk_used_math(tsk))
 		return 0;
 	if (!regs)
-		regs = (struct pt_regs *)tsk->thread.rsp0;
-	--regs;
+		regs = ((struct pt_regs *)tsk->thread.rsp0) - 1;
 	if (tsk == current)
 		unlazy_fpu(tsk);
 	set_fs(KERNEL_DS);