diff --git a/libc/calls/park.c b/libc/calls/park.c
index ec3df7c94c1..06f1f4233fe 100644
--- a/libc/calls/park.c
+++ b/libc/calls/park.c
@@ -48,8 +48,11 @@ static textwindows int _park_thread(uint32_t msdelay, sigset_t waitmask,
   if ((rc = _check_cancel()) != -1 && (rc = _check_signal(restartable)) != -1) {
     unassert((wi = WaitForSingleObject(sem, msdelay)) != -1u);
     if (wi != kNtWaitTimeout) {
+      _check_signal(false);
       rc = eintr();
       _check_cancel();
+    } else if ((rc = _check_signal(restartable))) {
+      _check_cancel();
     }
   }
   __sig_finishwait(om);
diff --git a/libc/calls/readwrite-nt.c b/libc/calls/readwrite-nt.c
index bd6bc46bf48..9f6e4884f26 100644
--- a/libc/calls/readwrite-nt.c
+++ b/libc/calls/readwrite-nt.c
@@ -193,8 +193,9 @@ sys_readwrite_nt(int fd, void *data, size_t size, ssize_t offset,
   // check and see if it was pthread_cancel() which committed the deed
   // in which case _check_cancel() can acknowledge the cancelation now
   // it's also fine to do nothing here; punt to next cancelation point
-  if (GetLastError() == kNtErrorOperationAborted && _check_cancel() == -1) {
-    return ecanceled();
+  if (GetLastError() == kNtErrorOperationAborted) {
+    if (_check_cancel() == -1) return ecanceled();
+    if (!eintered && _check_signal(false)) return eintr();
   }
 
   // if we chose to process a pending signal earlier then we preserve
diff --git a/libc/calls/sig.c b/libc/calls/sig.c
index 7650e8f48e2..c59d7dbd07a 100644
--- a/libc/calls/sig.c
+++ b/libc/calls/sig.c
@@ -128,8 +128,7 @@ static textwindows bool __sig_start(struct PosixThread *pt, int sig,
     return false;
   }
   if (pt->tib->tib_sigmask & (1ull << (sig - 1))) {
-    STRACE("tid %d masked %G delivering to tib_sigpending", _pthread_tid(pt),
-           sig);
+    STRACE("enqueing %G on %d", sig, _pthread_tid(pt));
     pt->tib->tib_sigpending |= 1ull << (sig - 1);
     return false;
   }
@@ -137,10 +136,6 @@ static textwindows bool __sig_start(struct PosixThread *pt, int sig,
     STRACE("terminating on %G due to no handler", sig);
     __sig_terminate(sig);
   }
-  if (*flags & SA_RESETHAND) {
-    STRACE("resetting %G handler", sig);
-    __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
-  }
   return true;
 }
 
@@ -153,6 +148,10 @@ textwindows int __sig_raise(int sig, int sic) {
   struct PosixThread *pt = _pthread_self();
   ucontext_t ctx = {.uc_sigmask = pt->tib->tib_sigmask};
   if (!__sig_start(pt, sig, &rva, &flags)) return 0;
+  if (flags & SA_RESETHAND) {
+    STRACE("resetting %G handler", sig);
+    __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
+  }
   siginfo_t si = {.si_signo = sig, .si_code = sic};
   struct NtContext nc;
   nc.ContextFlags = kNtContextFull;
@@ -232,30 +231,53 @@ static textwindows wontreturn void __sig_tramp(struct SignalFrame *sf) {
   __sig_restore(&sf->ctx);
 }
 
-static textwindows int __sig_killer(struct PosixThread *pt, int sig, int sic) {
-  uintptr_t th;
+static int __sig_killer(struct PosixThread *pt, int sig, int sic) {
+
+  // prepare for signal
   unsigned rva, flags;
-  if (!__sig_start(pt, sig, &rva, &flags)) return 0;
-  th = _pthread_syshand(pt);
-  uint32_t old_suspend_count;
-  old_suspend_count = SuspendThread(th);
-  if (old_suspend_count == -1u) {
+  if (!__sig_start(pt, sig, &rva, &flags)) {
+    return 0;
+  }
+
+  // take control of thread
+  // suspending the thread happens asynchronously
+  // however getting the context blocks until it's frozen
+  static pthread_spinlock_t killer_lock;
+  pthread_spin_lock(&killer_lock);
+  uintptr_t th = _pthread_syshand(pt);
+  if (SuspendThread(th) == -1u) {
     STRACE("SuspendThread failed w/ %d", GetLastError());
+    pthread_spin_unlock(&killer_lock);
     return ESRCH;
   }
-  if (old_suspend_count) {
-    STRACE("kill contention of %u on tid %d", old_suspend_count,
-           _pthread_tid(pt));
-    pt->tib->tib_sigpending |= 1ull << (sig - 1);
-    ResumeThread(th);
-    return 0;
-  }
   struct NtContext nc;
   nc.ContextFlags = kNtContextFull;
   if (!GetThreadContext(th, &nc)) {
     STRACE("GetThreadContext failed w/ %d", GetLastError());
+    ResumeThread(th);
+    pthread_spin_unlock(&killer_lock);
     return ESRCH;
   }
+  pthread_spin_unlock(&killer_lock);
+
+  // we can't preempt threads that are running in win32 code
+  if ((pt->tib->tib_sigmask & (1ull << (sig - 1))) ||
+      !((uintptr_t)__executable_start <= nc.Rip &&
+        nc.Rip < (uintptr_t)__privileged_start)) {
+    STRACE("enqueing %G on %d", sig, _pthread_tid(pt));
+    pt->tib->tib_sigpending |= 1ull << (sig - 1);
+    ResumeThread(th);
+    __sig_cancel(pt, sig, flags);
+    return 0;
+  }
+
+  // we're committed to delivering this signal now
+  if (flags & SA_RESETHAND) {
+    STRACE("resetting %G handler", sig);
+    __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
+  }
+
+  // inject trampoline function call into thread
   uintptr_t sp;
   if (__sig_should_use_altstack(flags, pt->tib)) {
     sp = (uintptr_t)pt->tib->tib_sigstack_addr + pt->tib->tib_sigstack_size;
@@ -307,7 +329,8 @@ textwindows void __sig_generate(int sig, int sic) {
   _pthread_lock();
   for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
     pt = POSIXTHREAD_CONTAINER(e);
-    if (atomic_load_explicit(&pt->pt_status, memory_order_acquire) <
+    if (pt != _pthread_self() &&
+        atomic_load_explicit(&pt->pt_status, memory_order_acquire) <
             kPosixThreadTerminated &&
         !(pt->tib->tib_sigmask & (1ull << (sig - 1)))) {
       mark = pt;
@@ -315,14 +338,14 @@ textwindows void __sig_generate(int sig, int sic) {
     }
   }
   _pthread_unlock();
-  ALLOW_SIGNALS;
   if (mark) {
     STRACE("generating %G by killing %d", sig, _pthread_tid(mark));
-    __sig_kill(mark, sig, sic);
+    __sig_killer(mark, sig, sic);
   } else {
     STRACE("all threads block %G so adding to pending signals of process", sig);
     __sig.pending |= 1ull << (sig - 1);
   }
+  ALLOW_SIGNALS;
 }
 
 static int __sig_crash_sig(struct NtExceptionPointers *ep, int *code) {
diff --git a/libc/sock/winsockblock.c b/libc/sock/winsockblock.c
index 04f36e9f901..9a0f18661ac 100644
--- a/libc/sock/winsockblock.c
+++ b/libc/sock/winsockblock.c
@@ -140,8 +140,9 @@ __winsock_block(int64_t handle, uint32_t flags, bool nonblock,
   if (eagained) {
     return eagain();
   }
-  if (WSAGetLastError() == kNtErrorOperationAborted && _check_cancel()) {
-    return ecanceled();
+  if (GetLastError() == kNtErrorOperationAborted) {
+    if (_check_cancel() == -1) return ecanceled();
+    if (!eintered && _check_signal(false)) return eintr();
   }
   if (eintered) {
     return eintr();
diff --git a/test/libc/calls/sig_test.c b/test/libc/calls/sig_test.c
index d1a0f024122..8fe87fb5cce 100644
--- a/test/libc/calls/sig_test.c
+++ b/test/libc/calls/sig_test.c
@@ -19,6 +19,7 @@
 #include "libc/sysv/consts/sig.h"
 #include "libc/atomic.h"
 #include "libc/calls/calls.h"
+#include "libc/calls/internal.h"
 #include "libc/calls/struct/sigaction.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
@@ -26,6 +27,7 @@
 #include "libc/nt/enum/context.h"
 #include "libc/nt/struct/context.h"
 #include "libc/nt/thread.h"
+#include "libc/runtime/clktck.h"
 #include "libc/sock/struct/pollfd.h"
 #include "libc/sysv/consts/poll.h"
 #include "libc/testlib/testlib.h"
@@ -64,6 +66,7 @@ TEST(SetThreadContext, test) {
   if (!IsWindows()) return;
   ASSERT_EQ(0, pthread_create(&th, 0, Worker, 0));
   while (!ready) donothing;
+  usleep(1000);
   int64_t hand = _pthread_syshand((struct PosixThread *)th);
   ASSERT_EQ(0, SuspendThread(hand));
   struct NtContext nc;
@@ -101,9 +104,9 @@ TEST(poll, interrupt) {
   signal(SIGUSR1, OnSig);
   ASSERT_SYS(0, 0, pipe(pfds));
   ASSERT_EQ(0, pthread_create(&th, 0, Worker2, 0));
-  for (int i = 0; i < 100; ++i) {
+  for (int i = 0; i < 20; ++i) {
     ASSERT_EQ(0, pthread_kill(th, SIGUSR1));
-    usleep(1000);
+    usleep(1e6 / CLK_TCK * 2);
   }
   isdone = true;
   ASSERT_EQ(0, pthread_kill(th, SIGUSR1));