[PATCH] x86_64: fix bug in csum_partial_copy_generic()

I was observing reproducible crashes on the "movw %bx,(%rsi)" instruction
below while a process in a recvfrom() system call was copying packet data
to user space.  The patch below fixes the exception table and causes the
crash to no longer reproduce.  Please apply.

Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/x86_64/lib/csum-copy.S b/arch/x86_64/lib/csum-copy.S
index 01808ec..72fd55e 100644 (file)
--- a/arch/x86_64/lib/csum-copy.S
+++ b/arch/x86_64/lib/csum-copy.S
@@ -188,8 +188,8 @@ csum_partial_copy_generic:
        source
        movw (%rdi),%bx
        adcl %ebx,%eax
-       dest
        decl %ecx
+       dest
        movw %bx,(%rsi)
        leaq 2(%rdi),%rdi
        leaq 2(%rsi),%rsi