diff --git a/src/libstd/sys/redox/ext/process.rs b/src/libstd/sys/redox/ext/process.rs
index 55824dc4c059..18aef768b5db 100644
--- a/src/libstd/sys/redox/ext/process.rs
+++ b/src/libstd/sys/redox/ext/process.rs
@@ -48,8 +48,7 @@ pub trait CommandExt {
     /// This also means that all resources such as file descriptors and
     /// memory-mapped regions got duplicated. It is your responsibility to make
     /// sure that the closure does not violate library invariants by making
-    /// invalid use of these duplicates.  Moreover, POSIX demands that you only
-    /// perform operations that are explicitly documented as async-signal-safe.
+    /// invalid use of these duplicates.
     ///
     /// When this closure is run, aspects such as the stdio file descriptors and
     /// working directory have successfully been changed, so output to these
diff --git a/src/libstd/sys/unix/ext/process.rs b/src/libstd/sys/unix/ext/process.rs
index ac0abc761ffb..d869a2013dc2 100644
--- a/src/libstd/sys/unix/ext/process.rs
+++ b/src/libstd/sys/unix/ext/process.rs
@@ -48,8 +48,7 @@ pub trait CommandExt {
     /// This also means that all resources such as file descriptors and
     /// memory-mapped regions got duplicated. It is your responsibility to make
     /// sure that the closure does not violate library invariants by making
-    /// invalid use of these duplicates.  Moreover, POSIX demands that you only
-    /// perform operations that are explicitly documented as async-signal-safe.
+    /// invalid use of these duplicates.
     ///
     /// When this closure is run, aspects such as the stdio file descriptors and
     /// working directory have successfully been changed, so output to these