tools/virtio: fix smp_mb on x86

mstsirkin · davem330 · commit 491847f3b29c · 2018-01-29T12:02:55.000-05:00
Offset 128 overlaps the last word of the redzone.
Use 132 which is always beyond that.

Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git 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

Original file line number	Diff line number	Diff line change
`@@ -111,7 +111,7 @@ static inline void busy_wait(void)`
`111`	`111`	`}`
`112`	`112`
`113`	`113`	`#if defined(__x86_64__) \|\| defined(__i386__)`
`114`		`-#define smp_mb() asm volatile("lock; addl $0,-128(%%rsp)" ::: "memory", "cc")`
	`114`	`+#define smp_mb() asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc")`
`115`	`115`	`#else`
`116`	`116`	`/*`
`117`	`117`	`* Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized`