diff --git a/libc/runtime/vfork.S b/libc/runtime/vfork.S
index 8af42732..197d6f76 100644
--- a/libc/runtime/vfork.S
+++ b/libc/runtime/vfork.S
@@ -20,6 +20,11 @@
 #include "libc/macros.internal.h"
 .privileged
 
+#ifdef __FSANITIZE_ADDRESS__
+vfork:	jmp	fork			# TODO: asan and vfork don't mix?
+	.endfn	vfork,globl
+#else
+
 //	Forks process without copying page tables.
 //
 //	This is the same as fork() except it's optimized for the case
@@ -75,3 +80,5 @@ vfork.bsd:
 	jmp	0b
 	.endfn	vfork.bsd
 #endif /* BSD */
+
+#endif /* __FSANITIZE_ADDRESS__ */
diff --git a/libc/stdio/fgetc.c b/libc/stdio/fgetc.c
index 034b9678..731e4b3e 100644
--- a/libc/stdio/fgetc.c
+++ b/libc/stdio/fgetc.c
@@ -23,11 +23,11 @@
  * @return byte in range 0..255, or -1 w/ errno
  */
 int fgetc(FILE *f) {
-  unsigned char b;
+  unsigned char b[1];
   if (f->beg < f->end) {
     return f->buf[f->beg++] & 0xff;
   } else {
-    if (!fread(&b, 1, 1, f)) return -1;
-    return b;
+    if (!fread(b, 1, 1, f)) return -1;
+    return b[0];
   }
 }
diff --git a/libc/stdio/popen.c b/libc/stdio/popen.c
index 50abc39c..d99bba67 100644
--- a/libc/stdio/popen.c
+++ b/libc/stdio/popen.c
@@ -33,7 +33,7 @@
  */
 FILE *popen(const char *cmdline, const char *mode) {
   FILE *f;
-  int dir, flags, pipefds[2];
+  int e, pid, dir, flags, pipefds[2];
   flags = fopenflags(mode);
   if ((flags & O_ACCMODE) == O_RDONLY) {
     dir = 0;
@@ -45,13 +45,28 @@ FILE *popen(const char *cmdline, const char *mode) {
   }
   if (pipe(pipefds) == -1) return NULL;
   fcntl(pipefds[dir], F_SETFD, FD_CLOEXEC);
-  if (!(f = fdopen(pipefds[dir], mode))) abort();
-  if ((f->pid = vfork()) == -1) abort();
-  if (!f->pid) {
-    dup2(pipefds[!dir], !dir);
-    systemexec(cmdline);
-    _exit(127);
+  if ((f = fdopen(pipefds[dir], mode))) {
+    switch ((pid = vfork())) {
+      case 0:
+        dup2(pipefds[!dir], !dir);
+        systemexec(cmdline);
+        _exit(127);
+      default:
+        f->pid = pid;
+        close(pipefds[!dir]);
+        return f;
+      case -1:
+        e = errno;
+        fclose(f);
+        close(pipefds[!dir]);
+        errno = e;
+        return NULL;
+    }
+  } else {
+    e = errno;
+    close(pipefds[0]);
+    close(pipefds[1]);
+    errno = e;
+    return NULL;
   }
-  close(pipefds[!dir]);
-  return f;
 }
diff --git a/libc/stdio/stdio.h b/libc/stdio/stdio.h
index 268913be..7d3d0649 100644
--- a/libc/stdio/stdio.h
+++ b/libc/stdio/stdio.h
@@ -14,7 +14,7 @@ COSMOPOLITAN_C_START_
 
 typedef struct FILE {
   uint8_t bufmode; /* 0x00 _IOFBF, etc. (ignored if fd=-1) */
-  bool noclose;    /* 0x01 for fake dup() */
+  bool noclose;    /* 0x01 for fake dup() todo delete! */
   uint32_t iomode; /* 0x04 O_RDONLY, etc. (ignored if fd=-1) */
   int32_t state;   /* 0x08 0=OK, -1=EOF, >0=errno */
   int fd;          /* 0x0c ≥0=fd, -1=closed|buffer */
diff --git a/test/libc/stdio/popen_test.c b/test/libc/stdio/popen_test.c
index 752b1131..c7d37b8e 100644
--- a/test/libc/stdio/popen_test.c
+++ b/test/libc/stdio/popen_test.c
@@ -23,7 +23,6 @@
 TEST(popen, test) {
   int ws;
   FILE *f;
-  /* TODO(jart): look into popen() asan error */
   f = popen("echo hi", "r");
   ASSERT_NE(NULL, f);
   EXPECT_EQ('h', fgetc(f));