diff --git a/src/file_tree.ml b/src/file_tree.ml
index 58844479..e04827f4 100644
--- a/src/file_tree.ml
+++ b/src/file_tree.ml
@@ -155,18 +155,46 @@ let ignore_file fn ~is_directory =
   (is_directory && (fn.[0] = '.' || fn.[0] = '_')) ||
   (fn.[0] = '.' && fn.[1] = '#')
 
+module File = struct
+  type t =
+    { ino : int
+    ; dev : int
+    }
+
+  let compare a b =
+    match Int.compare a.ino b.ino with
+    | Eq -> Int.compare a.dev b.dev
+    | ne -> ne
+
+  let dummy = { ino = 0; dev = 0 }
+
+  let of_stats (st : Unix.stats) =
+    { ino = st.st_ino
+    ; dev = st.st_dev
+    }
+end
+
+module File_map = Map.Make(File)
+
 let load ?(extra_ignored_subtrees=Path.Set.empty) path =
-  let rec walk path ~project ~ignored : Dir.t =
+  let rec walk path ~dirs_visited ~project ~ignored : Dir.t =
     let contents = lazy (
       let files, sub_dirs =
         Path.readdir path
         |> List.filter_partition_map ~f:(fun fn ->
           let path = Path.relative path fn in
-          let is_directory = Path.is_directory path in
+          let is_directory, file =
+            match Unix.stat (Path.to_string path) with
+            | exception _ -> (false, File.dummy)
+            | { st_kind = S_DIR; _ } as st ->
+              (true, File.of_stats st)
+            | _ ->
+              (false, File.dummy)
+          in
           if ignore_file fn ~is_directory then
             Skip
           else if is_directory then
-            Right (fn, path)
+            Right (fn, path, file)
           else
             Left fn)
       in
@@ -203,13 +231,27 @@ let load ?(extra_ignored_subtrees=Path.Set.empty) path =
           (dune_file, ignored_subdirs)
       in
       let sub_dirs =
-        List.fold_left sub_dirs ~init:String.Map.empty ~f:(fun acc (fn, path) ->
-          let ignored =
-            ignored
-            || String.Set.mem ignored_subdirs fn
-            || Path.Set.mem extra_ignored_subtrees path
-          in
-          String.Map.add acc fn (walk path ~project ~ignored))
+        List.fold_left sub_dirs ~init:String.Map.empty
+          ~f:(fun acc (fn, path, file) ->
+            let dirs_visited =
+              if Sys.win32 then
+                dirs_visited
+              else
+                match File_map.find dirs_visited file with
+                | None -> File_map.add dirs_visited file path
+                | Some first_path ->
+                  die "Path %s has already been scanned. \
+                       Cannot scan it again through symlink %s"
+                    (Path.to_string_maybe_quoted first_path)
+                    (Path.to_string_maybe_quoted path)
+            in
+            let ignored =
+              ignored
+              || String.Set.mem ignored_subdirs fn
+              || Path.Set.mem extra_ignored_subtrees path
+            in
+            String.Map.add acc fn
+              (walk path ~dirs_visited ~project ~ignored))
       in
       { Dir. files; sub_dirs; dune_file; project })
     in
@@ -218,7 +260,14 @@ let load ?(extra_ignored_subtrees=Path.Set.empty) path =
     ; ignored
     }
   in
-  let root = walk path ~ignored:false ~project:None in
+  let root =
+    walk path
+      ~dirs_visited:(File_map.singleton
+                       (File.of_stats (Unix.stat (Path.to_string path)))
+                       path)
+      ~ignored:false
+      ~project:None
+  in
   let dirs = Hashtbl.create 1024      in
   Hashtbl.add dirs Path.root root;
   { root; dirs }
diff --git a/src/stdune/path.ml b/src/stdune/path.ml
index ec8fd4ad..22c8a334 100644
--- a/src/stdune/path.ml
+++ b/src/stdune/path.ml
@@ -520,4 +520,3 @@ let change_extension ~ext t =
 let extension = Filename.extension
 
 let pp ppf t = Format.pp_print_string ppf (to_string t)
-
diff --git a/test/blackbox-tests/dune.inc b/test/blackbox-tests/dune.inc
index 3c9cf7b5..6863fa98 100644
--- a/test/blackbox-tests/dune.inc
+++ b/test/blackbox-tests/dune.inc
@@ -217,6 +217,16 @@
     test-cases/github761
     (progn (run ${exe:cram.exe} -test run.t) (diff? run.t run.t.corrected))))))
 
+(alias
+ ((name github764)
+  (deps ((package dune) (files_recursively_in test-cases/github764)))
+  (action
+   (chdir
+    test-cases/github764
+    (progn
+     (run ${exe:cram.exe} -skip-platforms win -test run.t)
+     (diff? run.t run.t.corrected))))))
+
 (alias
  ((name ignored_subdirs)
   (deps ((package dune) (files_recursively_in test-cases/ignored_subdirs)))
@@ -511,6 +521,7 @@
     (alias github734)
     (alias github759)
     (alias github761)
+    (alias github764)
     (alias ignored_subdirs)
     (alias include-loop)
     (alias inline_tests)
@@ -567,6 +578,7 @@
     (alias github734)
     (alias github759)
     (alias github761)
+    (alias github764)
     (alias ignored_subdirs)
     (alias include-loop)
     (alias inline_tests)
diff --git a/test/blackbox-tests/gen_tests.ml b/test/blackbox-tests/gen_tests.ml
index 505bc1e0..085c22b6 100644
--- a/test/blackbox-tests/gen_tests.ml
+++ b/test/blackbox-tests/gen_tests.ml
@@ -104,6 +104,7 @@ let exclusions =
   ; make "menhir"~external_deps:true
   ; make "utop"~external_deps:true
   ; make "configurator" ~skip_platforms:[Win]
+  ; make "github764" ~skip_platforms:[Win]
   ]
 
 let all_tests = lazy (
diff --git a/test/blackbox-tests/test-cases/github764/run.t b/test/blackbox-tests/test-cases/github764/run.t
new file mode 100644
index 00000000..2f04e5c7
--- /dev/null
+++ b/test/blackbox-tests/test-cases/github764/run.t
@@ -0,0 +1,36 @@
+  $ mkdir -p c1
+  $ cd c1 && ln -s . x
+  $ cd c1 && ln -s . y
+  $ cd c1 && dune build
+  Path . has already been scanned. Cannot scan it again through symlink x
+  [1]
+
+  $ mkdir -p c2/a c2/b
+  $ cd c2/a && ln -s ../b x
+  $ cd c2/b && ln -s ../a x
+  $ cd c2 && dune build
+  Path a has already been scanned. Cannot scan it again through symlink a/x/x
+  [1]
+
+  $ mkdir symlink-outside-root
+  $ cd symlink-outside-root && ln -s ../sample-exe sample
+  $ cd symlink-outside-root && jbuilder exec --root . -- sample/foo.exe
+  foo
+
+  $ mkdir -p symlink-outside-root2/root
+  $ mkdir -p symlink-outside-root2/other/a
+  $ mkdir -p symlink-outside-root2/other/b
+  $ cd symlink-outside-root2/other/a && ln -s ../b x
+  $ cd symlink-outside-root2/other/b && ln -s ../a x
+  $ cd symlink-outside-root2/root && ln -s ../other src
+  $ cd symlink-outside-root2/root && dune build
+  Path src/a has already been scanned. Cannot scan it again through symlink src/a/x/x
+  [1]
+
+  $ mkdir -p symlink-outside-root3/root
+  $ mkdir -p symlink-outside-root3/other
+  $ cd symlink-outside-root3/root  && ln -s ../other src
+  $ cd symlink-outside-root3/other && ln -s ../other foo
+  $ cd symlink-outside-root3/root && dune build
+  Path src has already been scanned. Cannot scan it again through symlink src/foo
+  [1]
diff --git a/test/blackbox-tests/test-cases/github764/sample-exe/dune b/test/blackbox-tests/test-cases/github764/sample-exe/dune
new file mode 100644
index 00000000..dab7cb21
--- /dev/null
+++ b/test/blackbox-tests/test-cases/github764/sample-exe/dune
@@ -0,0 +1,2 @@
+(executable
+ ((name foo)))
diff --git a/test/blackbox-tests/test-cases/github764/sample-exe/foo.ml b/test/blackbox-tests/test-cases/github764/sample-exe/foo.ml
new file mode 100644
index 00000000..d35be9f1
--- /dev/null
+++ b/test/blackbox-tests/test-cases/github764/sample-exe/foo.ml
@@ -0,0 +1 @@
+let () = print_endline "foo"