diff --git a/src/libraries/System.Private.CoreLib/src/Microsoft/Win32/SafeHandles/SafeFileHandle.Unix.cs b/src/libraries/System.Private.CoreLib/src/Microsoft/Win32/SafeHandles/SafeFileHandle.Unix.cs
index 7c92c4e081849a..ff5d30e6dc7ec4 100644
--- a/src/libraries/System.Private.CoreLib/src/Microsoft/Win32/SafeHandles/SafeFileHandle.Unix.cs
+++ b/src/libraries/System.Private.CoreLib/src/Microsoft/Win32/SafeHandles/SafeFileHandle.Unix.cs
@@ -333,7 +333,10 @@ private bool Init(string path, FileMode mode, FileAccess access, FileShare share
                     // and for regular files (most common case)
                     // avoid one extra sys call for determining whether file can be seeked
                     _canSeek = NullableBool.True;
-                    Debug.Assert(Interop.Sys.LSeek(this, 0, Interop.Sys.SeekWhence.SEEK_CUR) >= 0);
+
+                    // we exclude 0-length files from the assert because those may may be pseudofiles
+                    // (e.g. /proc/net/route) and these are not seekable on all systems
+                    Debug.Assert(status.Size == 0 || Interop.Sys.LSeek(this, 0, Interop.Sys.SeekWhence.SEEK_CUR) >= 0);
                 }
 
                 fileLength = status.Size;