diff --git a/src/exec.cpp b/src/exec.cpp
index ec6d299c8..f0e1f6af8 100644
--- a/src/exec.cpp
+++ b/src/exec.cpp
@@ -935,11 +935,10 @@ void exec_job(parser_t &parser, job_t *j) {
                 // output, so that we can truncate the file. Does not apply to /dev/null.
                 bool must_fork = redirection_is_to_real_file(stdout_io.get()) ||
                                  redirection_is_to_real_file(stderr_io.get());
-                if (!must_fork) {
-                    //we are handling reads directly in the main loop. Make sure source is unblocked.
-                    unblock_previous();
-                }
                 if (!must_fork && p->is_last_in_job) {
+                    //we are handling reads directly in the main loop. Make sure source is unblocked.
+                    //Note that we may still end up forking.
+                    unblock_previous();
                     const bool stdout_is_to_buffer = stdout_io && stdout_io->io_mode == IO_BUFFER;
                     const bool no_stdout_output = stdout_buffer.empty();
                     const bool no_stderr_output = stderr_buffer.empty();
diff --git a/src/postfork.cpp b/src/postfork.cpp
index 999324bd1..1e6e9fd29 100644
--- a/src/postfork.cpp
+++ b/src/postfork.cpp
@@ -78,7 +78,13 @@ bool child_set_group(job_t *j, process_t *p) {
         if (j->pgid == -2) {
             j->pgid = p->pid;
         }
+        //retry on EPERM because there's no way that a child cannot join an existing progress group
+        //because we are SIGSTOPing the previous job in the chain. Sometimes we have to try a few
+        //times to get the kernel to see the new group. (Linux 4.4.0)
         int failure = setpgid(p->pid, j->pgid);
+        while (failure == -1 && errno == EPERM) {
+            debug_safe(2, "Retrying setpgid in child process");
+        }
         // TODO: Figure out why we're testing whether the pgid is correct after attempting to
         // set it failed. This was added in commit 4e912ef8 from 2012-02-27.
         failure = failure && getpgid(p->pid) != j->pgid;