diff --git a/ape/ape.lds b/ape/ape.lds
index 11b1e0cea..7e8a045d1 100644
--- a/ape/ape.lds
+++ b/ape/ape.lds
@@ -304,7 +304,6 @@ SECTIONS {
     KEEP(*(.keep.text))
     *(.text .stub .text.*)
     KEEP(*(SORT_BY_NAME(.sort.text.*)))
-    *(.subrs)
 
     KEEP(*(.ape.pad.test));
     *(.test.unlikely)
@@ -402,6 +401,7 @@ SECTIONS {
 /*BEGIN: NT FORK COPYING */
     KEEP(*(.dataprologue))
     *(.data .data.*)
+    *(.subrs) /* for emacs */
     KEEP(*(SORT_BY_NAME(.sort.data.*)))
     . += . > 0 ? CODE_GRANULE : 0;
 
diff --git a/libc/intrin/kprintf.greg.c b/libc/intrin/kprintf.greg.c
index 82a031f89..b1952fa68 100644
--- a/libc/intrin/kprintf.greg.c
+++ b/libc/intrin/kprintf.greg.c
@@ -103,6 +103,7 @@
       break;                                 \
   }
 
+_Hide long __klog_handle;
 extern _Hide struct SymbolTable *__symtab;
 
 privileged static inline char *kadvance(char *p, char *e, long n) {
@@ -190,18 +191,30 @@ privileged bool kisdangerous(const void *p) {
   return true;
 }
 
-privileged dontinline void klog(const char *b, size_t n) {
+privileged static long kloghandle(void) {
+  if (__klog_handle) {
+    return __klog_handle;
+  } else if (!IsWindows()) {
+    return 2;
+  } else {
+    return __imp_GetStdHandle(kNtStdErrorHandle);
+  }
+}
+
+privileged void _klog(const char *b, size_t n) {
 #ifdef __x86_64__
   int e;
+  long h;
   bool cf;
   size_t i;
   uint16_t dx;
   uint32_t wrote;
   unsigned char al;
   long rax, rdi, rsi, rdx;
+  h = kloghandle();
   if (IsWindows()) {
     e = __imp_GetLastError();
-    __imp_WriteFile(__imp_GetStdHandle(kNtStdErrorHandle), b, n, &wrote, 0);
+    __imp_WriteFile(h, b, n, &wrote, 0);
     __imp_SetLastError(e);
   } else if (IsMetal()) {
     if (_weaken(_klog_vga)) _weaken(_klog_vga)(b, n);
@@ -220,11 +233,11 @@ privileged dontinline void klog(const char *b, size_t n) {
   } else {
     asm volatile("syscall"
                  : "=a"(rax), "=D"(rdi), "=S"(rsi), "=d"(rdx)
-                 : "0"(__NR_write), "1"(2), "2"(b), "3"(n)
+                 : "0"(__NR_write), "1"(h), "2"(b), "3"(n)
                  : "rcx", "r8", "r9", "r10", "r11", "memory", "cc");
   }
 #elif defined(__aarch64__)
-  register long r0 asm("x0") = (long)2;
+  register long r0 asm("x0") = (long)h;
   register long r1 asm("x1") = (long)b;
   register long r2 asm("x2") = (long)n;
   register long r8 asm("x8") = (long)__NR_write;
@@ -840,7 +853,7 @@ privileged void kvprintf(const char *fmt, va_list v) {
   size_t n;
   char b[4000];
   n = kformat(b, sizeof(b), fmt, v);
-  klog(b, MIN(n, sizeof(b) - 1));
+  _klog(b, MIN(n, sizeof(b) - 1));
 }
 
 /**
diff --git a/libc/intrin/kprintf.h b/libc/intrin/kprintf.h
index 5bc910675..98548985c 100644
--- a/libc/intrin/kprintf.h
+++ b/libc/intrin/kprintf.h
@@ -8,6 +8,7 @@ size_t ksnprintf(char *, size_t, const char *, ...);
 void kvprintf(const char *, va_list);
 size_t kvsnprintf(char *, size_t, const char *, va_list);
 bool kisdangerous(const void *);
+void _klog(const char *, size_t);
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
diff --git a/libc/log/backtrace2.c b/libc/log/backtrace2.c
index 26d9b63c9..5ccebe24e 100644
--- a/libc/log/backtrace2.c
+++ b/libc/log/backtrace2.c
@@ -148,11 +148,11 @@ static int PrintBacktraceUsingAddr2line(int fd, const struct StackFrame *bp) {
                        strlen(" (discriminator ") - 1)) &&
           (p3 = memchr(p2, '\n', got - (p2 - p1)))) {
         if (p3 > p2 && p3[-1] == '\r') --p3;
-        sys_write(2, p1, p2 - p1);
+        _klog(p1, p2 - p1);
         got -= p3 - p1;
         p1 += p3 - p1;
       } else {
-        sys_write(2, p1, got);
+        _klog(p1, got);
         break;
       }
     }
diff --git a/libc/log/log.h b/libc/log/log.h
index ff4e7ebe2..523ebdf06 100644
--- a/libc/log/log.h
+++ b/libc/log/log.h
@@ -40,6 +40,7 @@ void _meminfo(int);                    /* shows malloc statistics &c. */
 void _memsummary(int);                 /* light version of same thing */
 bool IsTerminalInarticulate(void) nosideeffect;
 const char *commandvenv(const char *, const char *);
+int LogKprintfToFile(const char *);
 const char *GetAddr2linePath(void);
 const char *GetGdbPath(void);
 void ShowCrashReports(void);
diff --git a/libc/log/logkprintftofile.c b/libc/log/logkprintftofile.c
new file mode 100644
index 000000000..778e1fab8
--- /dev/null
+++ b/libc/log/logkprintftofile.c
@@ -0,0 +1,57 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/log/log.h"
+#include "libc/sysv/consts/f.h"
+#include "libc/sysv/consts/o.h"
+
+static int __klog_fd;
+extern _Hide long __klog_handle;
+
+/**
+ * Redirects kprintf(), `--strace`, etc. output to file.
+ *
+ * @param path is filename to append to; if null is specified then
+ *     this file logging facility will be disabled; when the empty
+ *     string is specified, then the default path shall be used
+ * @return 0 on success, or -1 w/ errno
+ */
+int LogKprintfToFile(const char *path) {
+  int fd, dd;
+  if (!path) {
+    if (__klog_fd) {
+      __klog_handle = 0;
+      close(__klog_fd);
+      __klog_fd = 0;
+    }
+    return 0;
+  }
+  if (!*path) path = "/tmp/kprintf.log";
+  fd = open(path, O_WRONLY | O_APPEND | O_CREAT, 0644);
+  if (fd == -1) return -1;
+  dd = fcntl(fd, F_DUPFD_CLOEXEC, 100);
+  close(fd);
+  if (dd == -1) return -1;
+  if (__klog_fd) close(__klog_fd);
+  __klog_fd = dd;
+  __klog_handle = IsWindows() ? g_fds.p[dd].handle : dd;
+  return 0;
+}
diff --git a/libc/log/oncrash_amd64.c b/libc/log/oncrash_amd64.c
index d827a8c51..ffab0921b 100644
--- a/libc/log/oncrash_amd64.c
+++ b/libc/log/oncrash_amd64.c
@@ -235,11 +235,11 @@ relegated void ShowCrashReport(int err, int sig, struct siginfo *si,
     p = ShowGeneralRegisters(p, ctx);
     p = ShowSseRegisters(p, ctx);
     *p++ = '\n';
-    write(2, buf, p - buf);
+    _klog(buf, p - buf);
     ShowFunctionCalls(ctx);
   } else {
     *p++ = '\n';
-    write(2, buf, p - buf);
+    _klog(buf, p - buf);
   }
   kprintf("\n");
   if (!IsWindows()) __print_maps();
diff --git a/libc/runtime/finddebugbinary.c b/libc/runtime/finddebugbinary.c
index 0db821288..56b8fd209 100644
--- a/libc/runtime/finddebugbinary.c
+++ b/libc/runtime/finddebugbinary.c
@@ -61,7 +61,8 @@ static bool IsMyDebugBinaryImpl(const char *path) {
     // which is currently running in memory.
     if ((size = lseek(fd, 0, SEEK_END)) != -1 &&
         (map = mmap(0, size, PROT_READ, MAP_SHARED, fd, 0)) != MAP_FAILED) {
-      if (GetElfSymbolValue(map, size, "_etext", &value)) {
+      if (IsElf64Binary(map, size) &&
+          GetElfSymbolValue(map, size, "_etext", &value)) {
         res = !_etext || value == (uintptr_t)_etext;
       }
       munmap(map, size);
@@ -94,7 +95,8 @@ const char *FindDebugBinary(void) {
   if (!once) {
     p = GetProgramExecutableName();
     n = strlen(p);
-    if (n > 4 && READ32LE(p + n - 4) == READ32LE(".dbg")) {
+    if (n > 4 && READ32LE(p + n - 4) == READ32LE(".dbg") ||
+        IsMyDebugBinary(p)) {
       res = p;
     } else if (n > 4 && READ32LE(p + n - 4) == READ32LE(".com") &&
                n + 4 < ARRAYLEN(buf)) {
diff --git a/libc/sock/pselect.c b/libc/sock/pselect.c
index 22215fc40..2e7eaae3b 100644
--- a/libc/sock/pselect.c
+++ b/libc/sock/pselect.c
@@ -17,7 +17,10 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/cp.internal.h"
+#include "libc/calls/struct/itimerval.internal.h"
+#include "libc/calls/struct/sigset.internal.h"
 #include "libc/calls/struct/timespec.h"
+#include "libc/calls/struct/timespec.internal.h"
 #include "libc/calls/struct/timeval.h"
 #include "libc/dce.h"
 #include "libc/intrin/asan.internal.h"
@@ -25,6 +28,7 @@
 #include "libc/intrin/strace.internal.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/select.h"
+#include "libc/sysv/consts/nrlinux.h"
 #include "libc/sysv/errfuns.h"
 
 /**
@@ -99,7 +103,7 @@ int pselect(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 
   END_CANCELLATION_POINT;
   POLLTRACE("pselect(%d, %p, %p, %p, %s, %s) → %d% m", nfds, readfds, writefds,
-            exceptfds, DescribeTimeval(0, timeout), DescribeSigset(0, sigmask),
+            exceptfds, DescribeTimespec(0, timeout), DescribeSigset(0, sigmask),
             rc);
   return rc;
 }
diff --git a/libc/sock/select.c b/libc/sock/select.c
index a7d0df06b..25cca8f49 100644
--- a/libc/sock/select.c
+++ b/libc/sock/select.c
@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/sock/select.h"
 #include "libc/calls/cp.internal.h"
+#include "libc/calls/struct/itimerval.internal.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/calls/struct/timeval.h"
 #include "libc/dce.h"
diff --git a/tool/scripts/cosmoc++ b/tool/scripts/cosmoc++
index 20f8e5ebf..576a62538 100755
--- a/tool/scripts/cosmoc++
+++ b/tool/scripts/cosmoc++
@@ -30,7 +30,7 @@ exit 0
 fi
 
 CXX="/opt/cosmo/o/third_party/gcc/bin/x86_64-linux-musl-g++"
-CCFLAGS="-g -O2 -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
+CCFLAGS="-g -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
 CXXFLAGS="-fno-exceptions -fuse-cxa-atexit -fno-threadsafe-statics"
 CPPFLAGS="-DNDEBUG -nostdinc -iquote /opt/cosmo -isystem /opt/cosmos/include -isystem /opt/cosmo/libc/isystem -include libc/integral/normalize.inc"
 LDFLAGS="-static -no-pie -nostdlib -fuse-ld=bfd -Wl,-melf_x86_64 -Wl,--gc-sections -L/opt/cosmos/lib -Wl,-T,/opt/cosmo/o/ape/public/ape.lds /opt/cosmo/o/ape/ape-no-modify-self.o /opt/cosmo/o/libc/crt/crt.o"
diff --git a/tool/scripts/cosmocc b/tool/scripts/cosmocc
index dc1809ee7..1ee2816cd 100755
--- a/tool/scripts/cosmocc
+++ b/tool/scripts/cosmocc
@@ -33,7 +33,7 @@ exit 0
 fi
 
 CC="/opt/cosmo/o/third_party/gcc/bin/x86_64-linux-musl-gcc"
-CFLAGS="-g -O2 -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
+CFLAGS="-g -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
 CPPFLAGS="-DNDEBUG -nostdinc -iquote /opt/cosmo -isystem $COSMOS/include -isystem /opt/cosmo/libc/isystem -include libc/integral/normalize.inc"
 LDFLAGS="-static -no-pie -nostdlib -fuse-ld=bfd -Wl,-melf_x86_64 -Wl,--gc-sections -Wl,-z,max-page-size=0x1000 -L$COSMOS/lib -Wl,-T,/opt/cosmo/o/ape/public/ape.lds /opt/cosmo/o/ape/ape-no-modify-self.o /opt/cosmo/o/libc/crt/crt.o"
 LDLIBS="/opt/cosmo/o/cosmopolitan.a"