diff --git a/src/header/signal/mod.rs b/src/header/signal/mod.rs
index f049573..f3d665c 100644
--- a/src/header/signal/mod.rs
+++ b/src/header/signal/mod.rs
@@ -2,7 +2,10 @@
 //!
 //! See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/signal.h.html>.
 
-use core::{mem, ptr};
+use core::{
+    mem, ptr,
+    sync::atomic::Ordering,
+};
 
 use cbitset::BitSet;
 
@@ -32,6 +35,9 @@ pub mod sys;
 #[path = "redox.rs"]
 pub mod sys;
 
+mod signalfd;
+pub use self::signalfd::*;
+
 type SigSet = BitSet<[u64; 1]>;
 
 pub(crate) const SIG_DFL: usize = 0;
@@ -154,10 +160,15 @@ pub extern "C" fn killpg(pgrp: pid_t, sig: c_int) -> c_int {
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/pthread_kill.html>.
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn pthread_kill(thread: pthread_t, sig: c_int) -> c_int {
-    let os_tid = {
-        let pthread = unsafe { &*(thread as *const crate::pthread::Pthread) };
-        unsafe { pthread.os_tid.get().read() }
-    };
+    let pthread = unsafe { &*(thread as *const crate::pthread::Pthread) };
+    let os_tid = unsafe { pthread.os_tid.get().read() };
+    let flags = crate::pthread::PthreadFlags::from_bits_retain(
+        pthread.flags.load(Ordering::Acquire),
+    );
+    if flags.contains(crate::pthread::PthreadFlags::FINISHED) {
+        return errno::ESRCH;
+    }
+
     crate::header::pthread::e(unsafe { Sys::rlct_kill(os_tid, sig as usize) })
 }
 
@@ -168,12 +179,10 @@ pub unsafe extern "C" fn pthread_sigmask(
     set: *const sigset_t,
     oldset: *mut sigset_t,
 ) -> c_int {
-    // On Linux and Redox, pthread_sigmask and sigprocmask are equivalent
-    if unsafe { sigprocmask(how, set, oldset) } == 0 {
-        0
-    } else {
-        //TODO: Fix race
-        platform::ERRNO.get()
+    let filtered_set = unsafe { set.as_ref().map(|&block| block & !RLCT_SIGNAL_MASK) };
+    match unsafe { Sys::sigprocmask(how, filtered_set.as_ref(), oldset.as_mut()) } {
+        Ok(()) => 0,
+        Err(errno) => errno.0,
     }
 }