Process.OSX: fix thread safety (#100260)

ForNeVeR · web-flow · commit 78a895ffee8e · 2024-03-25T20:04:21.000-07:00
Without this fix, it was possible for another thread to see an incorrect
(zero) value of s_timeBase_numer because of a race condition.
diff --git a/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs b/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs
@@ -117,8 +117,8 @@ private static TimeSpan MapTime(ulong sysTime)
             if (denom == default)
             {
                 Interop.libSystem.mach_timebase_info_data_t timeBase = GetTimeBase();
-                s_timeBase_denom = denom = timeBase.denom;
                 s_timeBase_numer = timeBase.numer;
+                s_timeBase_denom = denom = timeBase.denom;
             }
             uint numer = s_timeBase_numer;
 

Original file line number	Diff line number	Diff line change
`@@ -117,8 +117,8 @@ private static TimeSpan MapTime(ulong sysTime)`
`117`	`117`	`if (denom == default)`
`118`	`118`	`{`
`119`	`119`	`Interop.libSystem.mach_timebase_info_data_t timeBase = GetTimeBase();`
`120`		`- s_timeBase_denom = denom = timeBase.denom;`
`121`	`120`	`s_timeBase_numer = timeBase.numer;`
	`121`	`+ s_timeBase_denom = denom = timeBase.denom;`
`122`	`122`	`}`
`123`	`123`	`uint numer = s_timeBase_numer;`
`124`	`124`