diff --git a/redox-rt/src/proc.rs b/redox-rt/src/proc.rs
index 63d947e669..7bc373d36c 100644
--- a/redox-rt/src/proc.rs
+++ b/redox-rt/src/proc.rs
@@ -999,6 +999,7 @@ pub fn fork_inner(initial_rsp: *mut usize, args: &ForkArgs) -> Result<usize> {
             thr_fd,
             pid,
         } = new_child_process(args)?;
+        let _ = syscall::write(1, b"FK:N1\n");
         new_proc_fd = proc_fd;
         new_thr_fd = thr_fd;
         new_pid = pid;
@@ -1010,10 +1011,12 @@ pub fn fork_inner(initial_rsp: *mut usize, args: &ForkArgs) -> Result<usize> {
                 let _ = syscall::write(1, b"FK:FB\n");
                 e
             })?;
+            let _ = syscall::write(1, b"FK:F1\n");
             new_filetable_fd = cur_filetable_fd.dup_into_upper(b"copy").map_err(|e| {
                 let _ = syscall::write(1, b"FK:CP\n");
                 e
             })?;
+            let _ = syscall::write(1, b"FK:F2\n");
 
             // This must be done before the address space is copied.
             let proc_fd = new_proc_fd.as_ref().map_or(usize::MAX, |p| p.as_raw_fd());
@@ -1047,15 +1050,18 @@ pub fn fork_inner(initial_rsp: *mut usize, args: &ForkArgs) -> Result<usize> {
                 let _ = syscall::write(1, b"FK:CA\n");
                 e
             })?;
+            let _ = syscall::write(1, b"FK:A0\n");
 
             let cur_addr_space_fd = cur_thr_fd.dup_into_upper(b"addrspace").map_err(|e| {
                 let _ = syscall::write(1, b"FK:AS\n");
                 e
             })?;
+            let _ = syscall::write(1, b"FK:A1\n");
             let new_addr_space_fd = cur_addr_space_fd.dup_into_upper(b"exclusive").map_err(|e| {
                 let _ = syscall::write(1, b"FK:EX\n");
                 e
             })?;
+            let _ = syscall::write(1, b"FK:A2\n");
 
             let mut grant_desc_buf = [GrantDesc::default(); 16];
             loop {
@@ -1116,6 +1122,7 @@ pub fn fork_inner(initial_rsp: *mut usize, args: &ForkArgs) -> Result<usize> {
                     )?;
                 }
             }
+            let _ = syscall::write(1, b"FK:A3\n");
             #[cfg(any(
                 target_arch = "x86_64",
                 target_arch = "aarch64",
@@ -1134,6 +1141,7 @@ pub fn fork_inner(initial_rsp: *mut usize, args: &ForkArgs) -> Result<usize> {
                 initial_rsp as usize,
             );
             new_addr_space_sel_fd.write(&buf)?;
+            let _ = syscall::write(1, b"FK:A4\n");
         }
         {
             // Reuse the same sigaltstack and signal entry (all memory will be re-mapped CoW later).
@@ -1142,7 +1150,9 @@ pub fn fork_inner(initial_rsp: *mut usize, args: &ForkArgs) -> Result<usize> {
             // reference to the TCB and whatever pages stores the signal proc control struct.
             {
                 let new_sighandler_fd = new_thr_fd.dup_into_upper(b"sighandler")?;
+                let _ = syscall::write(1, b"FK:S0\n");
                 new_sighandler_fd.write(&crate::signal::current_setsighandler_struct())?;
+                let _ = syscall::write(1, b"FK:S1\n");
             }
             if let Some(ref proc_fd) = new_proc_fd {
                 proc_call(
@@ -1151,37 +1161,47 @@ pub fn fork_inner(initial_rsp: *mut usize, args: &ForkArgs) -> Result<usize> {
                     CallFlags::empty(),
                     &[ProcCall::SyncSigPctl as u64],
                 )?;
+                let _ = syscall::write(1, b"FK:P1\n");
                 thread_call(
                     new_thr_fd.as_raw_fd(),
                     &mut [],
                     CallFlags::empty(),
                     &[ThreadCall::SyncSigTctl as u64],
                 )?;
+                let _ = syscall::write(1, b"FK:T1\n");
             }
         }
         {
             // Copy environment registers.
             let cur_env_regs_fd = cur_thr_fd.dup_into_upper(b"regs/env")?;
+            let _ = syscall::write(1, b"FK:E0\n");
             let new_env_regs_fd = new_thr_fd.dup_into_upper(b"regs/env")?;
+            let _ = syscall::write(1, b"FK:E1\n");
 
             let mut env_regs = syscall::EnvRegisters::default();
             cur_env_regs_fd.read(&mut env_regs)?;
             new_env_regs_fd.write(&env_regs)?;
+            let _ = syscall::write(1, b"FK:E2\n");
         }
     }
     {
         // TODO: Use file descriptor forwarding or something similar to avoid copying the file
         // table in the kernel.
         let new_filetable_sel_fd = new_thr_fd.dup_into_upper(b"current-filetable")?;
+        let _ = syscall::write(1, b"FK:FT0\n");
         new_filetable_sel_fd.write(&usize::to_ne_bytes(new_filetable_fd.as_raw_fd()))?;
+        let _ = syscall::write(1, b"FK:FT1\n");
     }
     new_filetable_fd.call_wo(
         &new_filetable_fd.as_raw_fd().to_ne_bytes(),
         syscall::CallFlags::FD | syscall::CallFlags::FD_CLONE,
         &[new_filetable_fd.as_raw_fd() as u64],
     )?;
+    let _ = syscall::write(1, b"FK:FT2\n");
     let start_fd = new_thr_fd.dup_into_upper(b"start")?;
+    let _ = syscall::write(1, b"FK:ST0\n");
     start_fd.write(&[0])?;
+    let _ = syscall::write(1, b"FK:ST1\n");
     Ok(new_pid)
 }