Fix a PAL spin lock issue (#19606)

kouvel · web-flow · commit 9663131aecb3 · 2018-08-28T11:41:51.000-07:00
Fixes https://github.com/dotnet/coreclr/issues/18486 - Lock release needs to be at least volatile
diff --git a/src/pal/src/synchobj/mutex.cpp b/src/pal/src/synchobj/mutex.cpp
@@ -804,7 +804,7 @@ void SPINLOCKAcquire (LONG * lock, unsigned int flags)
 
 void SPINLOCKRelease (LONG * lock)
 {
-    *lock = 0;
+    VolatileStore(lock, 0);
 }
 
 DWORD SPINLOCKTryAcquire (LONG * lock)

Original file line number	Diff line number	Diff line change
`@@ -804,7 +804,7 @@ void SPINLOCKAcquire (LONG * lock, unsigned int flags)`
`804`	`804`
`805`	`805`	`void SPINLOCKRelease (LONG * lock)`
`806`	`806`	`{`
`807`		`- *lock = 0;`
	`807`	`+ VolatileStore(lock, 0);`
`808`	`808`	`}`
`809`	`809`
`810`	`810`	`DWORD SPINLOCKTryAcquire (LONG * lock)`