diff --git a/vendor.conf b/vendor.conf
index 63077d9893..1c8fb62c2d 100755
--- a/vendor.conf
+++ b/vendor.conf
@@ -81,7 +81,7 @@ github.com/xeipuuv/gojsonschema                     93e72a773fade158921402d6a24c
 golang.org/x/crypto                                 38d8ce5564a5b71b2e3a00553993f1b9a7ae852f
 golang.org/x/net                                    eb5bcb51f2a31c7d5141d810b70815c05d9c9146
 golang.org/x/oauth2                                 ef147856a6ddbb60760db74283d2424e98c87bff
-golang.org/x/sync                                   42b317875d0fa942474b76e1b46a6060d720ae6e
+golang.org/x/sync                                   e225da77a7e68af35c70ccbf71af2b83e6acac3c
 golang.org/x/sys                                    d455e41777fca6e8a5a79e34a14b8368bc11d9ba
 golang.org/x/text                                   f21a4dfb5e38f5895301dc265a8def02365cc3d0 # v0.3.0
 golang.org/x/time                                   fbb02b2291d28baffd63558aa44b4b56f178d650
diff --git a/vendor/golang.org/x/sync/semaphore/semaphore.go b/vendor/golang.org/x/sync/semaphore/semaphore.go
index 2096ca3a00..ac53e733e7 100644
--- a/vendor/golang.org/x/sync/semaphore/semaphore.go
+++ b/vendor/golang.org/x/sync/semaphore/semaphore.go
@@ -32,9 +32,9 @@ type Weighted struct {
 	waiters list.List
 }
 
-// Acquire acquires the semaphore with a weight of n, blocking only until ctx
-// is done. On success, returns nil. On failure, returns ctx.Err() and leaves
-// the semaphore unchanged.
+// Acquire acquires the semaphore with a weight of n, blocking until resources
+// are available or ctx is done. On success, returns nil. On failure, returns
+// ctx.Err() and leaves the semaphore unchanged.
 //
 // If ctx is already done, Acquire may still succeed without blocking.
 func (s *Weighted) Acquire(ctx context.Context, n int64) error {