diff --git a/man7/pid_namespaces.7 b/man7/pid_namespaces.7
index 856905866..a56bf4476 100644
--- a/man7/pid_namespaces.7
+++ b/man7/pid_namespaces.7
@@ -146,6 +146,10 @@ or
 .BR unshare (2).
 PID namespaces thus form a tree,
 with all namespaces ultimately tracing their ancestry to the root namespace.
+Since Linux 3.7,
+.\" commit f2302505775fd13ba93f034206f1e2a587017929
+.\" The kernel constant MAX_PID_NS_LEVEL
+the kernel limits the maximum nesting depth for PID namespaces to 32.
 
 A process is visible to other processes in its PID namespace,
 and to the processes in each direct ancestor PID namespace