[PATCH net-next 12/12] tools/virtio: fix smp_mb on x86

From: Michael S. Tsirkin
Date: Thu Jan 25 2018 - 18:37:12 EST


Offset 128 overlaps the last word of the redzone.
Use 132 which is always beyond that.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
tools/virtio/ringtest/main.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/virtio/ringtest/main.h b/tools/virtio/ringtest/main.h
index 593a328..301d59b 100644
--- a/tools/virtio/ringtest/main.h
+++ b/tools/virtio/ringtest/main.h
@@ -111,7 +111,7 @@ static inline void busy_wait(void)
}

#if defined(__x86_64__) || defined(__i386__)
-#define smp_mb() asm volatile("lock; addl $0,-128(%%rsp)" ::: "memory", "cc")
+#define smp_mb() asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc")
#else
/*
* Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized
--
MST