Index: user/pho/stress2/misc/syzkaller26.sh
===================================================================
--- user/pho/stress2/misc/syzkaller26.sh	(revision 368095)
+++ user/pho/stress2/misc/syzkaller26.sh	(revision 368096)
@@ -1,167 +1,168 @@
 #!/bin/sh
 
 # panic: Bad link elm 0xfffff8001a83db00 prev->next != elm
 # cpuid = 21
 # time = 1605387390
 # KDB: stack backtrace:
 # db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0100a983e0
 # vpanic() at vpanic+0x182/frame 0xfffffe0100a98430
 # panic() at panic+0x43/frame 0xfffffe0100a98490
 # _callout_stop_safe() at _callout_stop_safe+0x726/frame 0xfffffe0100a98520
 # filt_timerdetach() at filt_timerdetach+0x20/frame 0xfffffe0100a98540
 # kqueue_drain() at kqueue_drain+0x2c8/frame 0xfffffe0100a98580
 # kqueue_close() at kqueue_close+0x7d/frame 0xfffffe0100a985c0
 # _fdrop() at _fdrop+0x1b/frame 0xfffffe0100a985e0
 # closef() at closef+0x1ea/frame 0xfffffe0100a98670
 # fdescfree_fds() at fdescfree_fds+0x8c/frame 0xfffffe0100a986d0
 # fdescfree() at fdescfree+0x3cd/frame 0xfffffe0100a987a0
 # exit1() at exit1+0x487/frame 0xfffffe0100a98810
 # sigexit() at sigexit+0x15c/frame 0xfffffe0100a98ae0
 # postsig() at postsig+0x2cc/frame 0xfffffe0100a98bb0
 # ast() at ast+0x5eb/frame 0xfffffe0100a98bf0
 # doreti_ast() at doreti_ast+0x1f/frame 0x7fffffffe570
 # KDB: enter: panic
 # [ thread pid 82279 tid 100717 ]
 # Stopped at      kdb_enter+0x37: movq    $0,0x10aa7f6(%rip)
 # db> x/s version
 # version:        FreeBSD 13.0-CURRENT #0 r367672: Sat Nov 14 08:42:14 CET 2020
 # pho@t2.osted.lan:/usr/src/sys/amd64/compile/PHO
 # db>
 
 # $FreeBSD$
 
 [ `uname -p` != "amd64" ] && exit 0
 
 # Fixed by r367849
 
 . ../default.cfg
 cat > /tmp/syzkaller26.c <<EOF
 // https://syzkaller.appspot.com/bug?id=95ac7e30218c63bc9322b1dd775101f8f88de4ff
 // autogenerated by syzkaller (https://github.com/google/syzkaller)
 // Reported-by: syzbot+1b27e0237aa22d8adffa@syzkaller.appspotmail.com
 
 #define _GNU_SOURCE
 
 #include <sys/types.h>
 
 #include <pwd.h>
 #include <signal.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/endian.h>
 #include <sys/syscall.h>
 #include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
 
 static void kill_and_wait(int pid, int* status)
 {
   kill(pid, SIGKILL);
   while (waitpid(-1, status, 0) != pid) {
   }
 }
 
 static void sleep_ms(uint64_t ms)
 {
   usleep(ms * 1000);
 }
 
 static uint64_t current_time_ms(void)
 {
   struct timespec ts;
   if (clock_gettime(CLOCK_MONOTONIC, &ts))
     exit(1);
   return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
 }
 
 static void execute_one(void);
 
 #define WAIT_FLAGS 0
 
 static void loop(void)
 {
   int iter = 0;
   for (;; iter++) {
     int pid = fork();
     if (pid < 0)
       exit(1);
     if (pid == 0) {
       execute_one();
       exit(0);
     }
     int status = 0;
     uint64_t start = current_time_ms();
     for (;;) {
       if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
         break;
       sleep_ms(1);
       if (current_time_ms() - start < 5 * 1000)
         continue;
       kill_and_wait(pid, &status);
       break;
     }
   }
 }
 
 uint64_t r[1] = {0xffffffffffffffff};
 
 void execute_one(void)
 {
   intptr_t res = 0;
   res = syscall(SYS_kqueue);
   if (res != -1)
     r[0] = res;
   *(uint64_t*)0x20000000 = 3;
   *(uint16_t*)0x20000008 = 0xfff3;
   *(uint16_t*)0x2000000a = 0x4000;
   *(uint32_t*)0x2000000c = 0x1000000;
   *(uint64_t*)0x20000010 = 0xe;
   *(uint64_t*)0x20000018 = 0xff;
   *(uint64_t*)0x20000020 = 2;
   *(uint64_t*)0x20000028 = 2;
   *(uint64_t*)0x20000030 = 4;
   *(uint64_t*)0x20000038 = 0xffffffffffffff90;
   *(uint64_t*)0x20000040 = 0x101;
   *(uint16_t*)0x20000048 = 0xfff6;
   *(uint16_t*)0x2000004a = 0x22;
   *(uint32_t*)0x2000004c = 0x20;
   *(uint64_t*)0x20000050 = 0xe1;
   *(uint64_t*)0x20000058 = -1;
   *(uint64_t*)0x20000060 = 0x81;
   *(uint64_t*)0x20000068 = 4;
   *(uint64_t*)0x20000070 = 0x8000;
   *(uint64_t*)0x20000078 = 9;
   *(uint64_t*)0x20000080 = 0;
   *(uint16_t*)0x20000088 = 0xfff9;
   *(uint16_t*)0x2000008a = 0xefc9;
   *(uint32_t*)0x2000008c = 4;
   *(uint64_t*)0x20000090 = 0;
   *(uint64_t*)0x20000098 = 0x400;
   *(uint64_t*)0x200000a0 = 0x2e77;
   *(uint64_t*)0x200000a8 = 2;
   *(uint64_t*)0x200000b0 = 0x7fffffff;
   *(uint64_t*)0x200000b8 = 7;
   syscall(SYS_kevent, r[0], 0x20000000ul, 3ul, 0x200000c0ul, 9ul, 0ul);
 }
 int main(void)
 {
+  sleep(2);	/* pho */
   syscall(SYS_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x1012ul, -1, 0ul);
   loop();
   return 0;
 }
 EOF
 mycc -o /tmp/syzkaller26 -Wall -Wextra -O0 /tmp/syzkaller26.c ||
     exit 1
 
 (cd ../testcases/swap; ./swap -t 1m -i 20 -h > /dev/null 2>&1) &
 for i in `jot 256`; do
 	(cd /tmp; timeout 3m ./syzkaller26) &
 done
 wait
 
 rm -rf /tmp/syzkaller26 syzkaller26.c /tmp/syzkaller.*
 exit 0