diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c
index 58d484280a..eb51139e51 100644
--- a/src/udev/udev-event.c
+++ b/src/udev/udev-event.c
@@ -534,6 +534,7 @@ static int on_spawn_io(sd_event_source *s, int fd, uint32_t revents, void *userd
         char buf[4096], *p;
         size_t size;
         ssize_t l;
+        int r;
 
         assert(spawn);
         assert(fd == spawn->fd_stdout || fd == spawn->fd_stderr);
@@ -549,9 +550,11 @@ static int on_spawn_io(sd_event_source *s, int fd, uint32_t revents, void *userd
 
         l = read(fd, p, size - 1);
         if (l < 0) {
-                if (errno != EAGAIN)
-                        log_device_error_errno(spawn->device, errno,
-                                               "Failed to read stdout of '%s': %m", spawn->cmd);
+                if (errno == EAGAIN)
+                        goto reenable;
+
+                log_device_error_errno(spawn->device, errno,
+                                       "Failed to read stdout of '%s': %m", spawn->cmd);
 
                 return 0;
         }
@@ -574,6 +577,16 @@ static int on_spawn_io(sd_event_source *s, int fd, uint32_t revents, void *userd
                                          fd == spawn->fd_stdout ? "out" : "err", *q);
         }
 
+
+        if (l == 0)
+                return 0;
+
+        /* Re-enable the event source if we did not encounter EOF */
+reenable:
+        r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
+        if (r < 0)
+                log_device_error_errno(spawn->device, r,
+                                       "Failed to reactivate IO source of '%s'", spawn->cmd);
         return 0;
 }
 
@@ -634,6 +647,9 @@ static int on_spawn_sigchld(sd_event_source *s, const siginfo_t *si, void *userd
 
 static int spawn_wait(Spawn *spawn) {
         _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+        _cleanup_(sd_event_source_unrefp) sd_event_source *sigchld_source = NULL;
+        _cleanup_(sd_event_source_unrefp) sd_event_source *stdout_source = NULL;
+        _cleanup_(sd_event_source_unrefp) sd_event_source *stderr_source = NULL;
         int r;
 
         assert(spawn);
@@ -670,20 +686,31 @@ static int spawn_wait(Spawn *spawn) {
         }
 
         if (spawn->fd_stdout >= 0) {
-                r = sd_event_add_io(e, NULL, spawn->fd_stdout, EPOLLIN, on_spawn_io, spawn);
+                r = sd_event_add_io(e, &stdout_source, spawn->fd_stdout, EPOLLIN, on_spawn_io, spawn);
+                if (r < 0)
+                        return r;
+                r = sd_event_source_set_enabled(stdout_source, SD_EVENT_ONESHOT);
                 if (r < 0)
                         return r;
         }
 
         if (spawn->fd_stderr >= 0) {
-                r = sd_event_add_io(e, NULL, spawn->fd_stderr, EPOLLIN, on_spawn_io, spawn);
+                r = sd_event_add_io(e, &stderr_source, spawn->fd_stderr, EPOLLIN, on_spawn_io, spawn);
+                if (r < 0)
+                        return r;
+                r = sd_event_source_set_enabled(stderr_source, SD_EVENT_ONESHOT);
                 if (r < 0)
                         return r;
         }
 
-        r = sd_event_add_child(e, NULL, spawn->pid, WEXITED, on_spawn_sigchld, spawn);
+        r = sd_event_add_child(e, &sigchld_source, spawn->pid, WEXITED, on_spawn_sigchld, spawn);
         if (r < 0)
                 return r;
+        /* SIGCHLD should be processed after IO is complete */
+        r = sd_event_source_set_priority(sigchld_source, SD_EVENT_PRIORITY_NORMAL + 1);
+        if (r < 0)
+                return r;
+
 
         return sd_event_loop(e);
 }