runtime: donate racectx to g0 in ReadMetricsSlow

[gostls13.git] / src / runtime / export_test.go

diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index 96b3a8dd93b41a7feaf44c72d4846fcbced3b1ee..b60c1f0a69d1d44dc5bfa6c7f4e81865234556b1 100644 (file)
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -425,6 +425,10 @@ func ReadMetricsSlow(memStats *MemStats, samplesp unsafe.Pointer, len, cap int)
        initMetrics()
 
        systemstack(func() {
+               // Donate the racectx to g0. readMetricsLocked calls into the race detector
+               // via map access.
+               getg().racectx = getg().m.curg.racectx
+
                // Read the metrics once before in case it allocates and skews the metrics.
                // readMetricsLocked is designed to only allocate the first time it is called
                // with a given slice of samples. In effect, this extra read tests that this
@@ -442,6 +446,9 @@ func ReadMetricsSlow(memStats *MemStats, samplesp unsafe.Pointer, len, cap int)
                // system stack with readmemstats_m so that we don't call into
                // the stack allocator and adjust metrics between there and here.
                readMetricsLocked(samplesp, len, cap)
+
+               // Undo the donation.
+               getg().racectx = 0
        })
        metricsUnlock()