1#!/bin/sh 2 3# Fatal trap 18: integer divide fault while in kernel mode 4# cpuid = 0; apic id = 00 5# instruction pointer = 0x20:0xffffffff80c310ee 6# stack pointer = 0x28:0xfffffe0131a629e0 7# frame pointer = 0x28:0xfffffe0131a62a30 8# code segment = base 0x0, limit 0xfffff, type 0x1b 9# = DPL 0, pres 1, long 1, def32 0, gran 1 10# processor eflags = interrupt enabled, resume, IOPL = 0 11# current process = 12 (swi4: clock (0)) 12# trap number = 18 13# panic: integer divide fault 14# cpuid = 0 15# time = 1618722013 16# KDB: stack backtrace: 17# db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0131a626f0 18# vpanic() at vpanic+0x181/frame 0xfffffe0131a62740 19# panic() at panic+0x43/frame 0xfffffe0131a627a0 20# trap_fatal() at trap_fatal+0x387/frame 0xfffffe0131a62800 21# trap() at trap+0xa4/frame 0xfffffe0131a62910 22# calltrap() at calltrap+0x8/frame 0xfffffe0131a62910 23# --- trap 0x12, rip = 0xffffffff80c310ee, rsp = 0xfffffe0131a629e0, rbp = 0xfffffe0131a62a30 --- 24# realtimer_expire_l() at realtimer_expire_l+0xee/frame 0xfffffe0131a62a30 25# softclock_call_cc() at softclock_call_cc+0x15d/frame 0xfffffe0131a62b00 26# softclock() at softclock+0x66/frame 0xfffffe0131a62b20 27# ithread_loop() at ithread_loop+0x279/frame 0xfffffe0131a62bb0 28# fork_exit() at fork_exit+0x80/frame 0xfffffe0131a62bf0 29# fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0131a62bf0 30# --- trap 0, rip = 0, rsp = 0, rbp = 0 --- 31# KDB: enter: panic 32# [ thread pid 12 tid 100161 ] 33# Stopped at kdb_enter+0x37: movq $0,0x1283f9e(%rip) 34# db> x/s version 35# version: FreeBSD 14.0-CURRENT #0 main-n246123-21afed4b1d1-dirty: Sat Apr 17 07:39:42 CEST 2021 36# pho@t2.osted.lan:/usr/src/sys/amd64/compile/PHO 37# db> 38 39[ `uname -p` != "amd64" ] && exit 0 40 41. ../default.cfg 42cat > /tmp/syzkaller33.c <<EOF 43// https://syzkaller.appspot.com/bug?id=38b58493445d524070d1a7cd73612f8cc9d01f39 44// autogenerated by syzkaller (https://github.com/google/syzkaller) 45// Reported-by: syzbot+5ab360bd3d3e3c5a6e0e@syzkaller.appspotmail.com 46 47#define _GNU_SOURCE 48 49#include <sys/types.h> 50 51#include <pwd.h> 52#include <signal.h> 53#include <stdarg.h> 54#include <stdbool.h> 55#include <stdint.h> 56#include <stdio.h> 57#include <stdlib.h> 58#include <string.h> 59#include <sys/endian.h> 60#include <sys/syscall.h> 61#include <sys/wait.h> 62#include <time.h> 63#include <unistd.h> 64 65static void kill_and_wait(int pid, int* status) 66{ 67 kill(pid, SIGKILL); 68 while (waitpid(-1, status, 0) != pid) { 69 } 70} 71 72static void sleep_ms(uint64_t ms) 73{ 74 usleep(ms * 1000); 75} 76 77static uint64_t current_time_ms(void) 78{ 79 struct timespec ts; 80 if (clock_gettime(CLOCK_MONOTONIC, &ts)) 81 exit(1); 82 return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; 83} 84 85static void execute_one(void); 86 87#define WAIT_FLAGS 0 88 89static void loop(void) 90{ 91 int iter __unused = 0; 92 for (;; iter++) { 93 int pid = fork(); 94 if (pid < 0) 95 exit(1); 96 if (pid == 0) { 97 execute_one(); 98 exit(0); 99 } 100 int status = 0; 101 uint64_t start = current_time_ms(); 102 for (;;) { 103 if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) 104 break; 105 sleep_ms(1); 106 if (current_time_ms() - start < 5000) { 107 continue; 108 } 109 kill_and_wait(pid, &status); 110 break; 111 } 112 } 113} 114 115uint64_t r[1] = {0x0}; 116 117void execute_one(void) 118{ 119 intptr_t res = 0; 120 res = syscall(SYS_ktimer_create, 0ul, 0ul, 0x200011c0ul); 121 if (res != -1) 122 r[0] = *(uint32_t*)0x200011c0; 123 *(uint64_t*)0x20001200 = 0x800000000000000; 124 *(uint64_t*)0x20001208 = 0; 125 *(uint64_t*)0x20001210 = 0; 126 *(uint64_t*)0x20001218 = 0xa2b; 127 syscall(SYS_ktimer_settime, r[0], 1ul, 0x20001200ul, 0ul); 128} 129int main(void) 130{ 131 syscall(SYS_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x1012ul, -1, 0ul); 132 loop(); 133 return 0; 134} 135EOF 136mycc -o /tmp/syzkaller33 -Wall -Wextra -O0 /tmp/syzkaller33.c || 137 exit 1 138 139(cd /tmp; timeout 3m ./syzkaller33) 140 141rm -rf /tmp/syzkaller33 /tmp/syzkaller33.c /tmp/syzkaller.* 142exit 0 143