#!/bin/sh # Fatal trap 18: integer divide fault while in kernel mode # cpuid = 0; apic id = 00 # instruction pointer = 0x20:0xffffffff80c310ee # stack pointer = 0x28:0xfffffe0131a629e0 # frame pointer = 0x28:0xfffffe0131a62a30 # code segment = base 0x0, limit 0xfffff, type 0x1b # = DPL 0, pres 1, long 1, def32 0, gran 1 # processor eflags = interrupt enabled, resume, IOPL = 0 # current process = 12 (swi4: clock (0)) # trap number = 18 # panic: integer divide fault # cpuid = 0 # time = 1618722013 # KDB: stack backtrace: # db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0131a626f0 # vpanic() at vpanic+0x181/frame 0xfffffe0131a62740 # panic() at panic+0x43/frame 0xfffffe0131a627a0 # trap_fatal() at trap_fatal+0x387/frame 0xfffffe0131a62800 # trap() at trap+0xa4/frame 0xfffffe0131a62910 # calltrap() at calltrap+0x8/frame 0xfffffe0131a62910 # --- trap 0x12, rip = 0xffffffff80c310ee, rsp = 0xfffffe0131a629e0, rbp = 0xfffffe0131a62a30 --- # realtimer_expire_l() at realtimer_expire_l+0xee/frame 0xfffffe0131a62a30 # softclock_call_cc() at softclock_call_cc+0x15d/frame 0xfffffe0131a62b00 # softclock() at softclock+0x66/frame 0xfffffe0131a62b20 # ithread_loop() at ithread_loop+0x279/frame 0xfffffe0131a62bb0 # fork_exit() at fork_exit+0x80/frame 0xfffffe0131a62bf0 # fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0131a62bf0 # --- trap 0, rip = 0, rsp = 0, rbp = 0 --- # KDB: enter: panic # [ thread pid 12 tid 100161 ] # Stopped at kdb_enter+0x37: movq $0,0x1283f9e(%rip) # db> x/s version # version: FreeBSD 14.0-CURRENT #0 main-n246123-21afed4b1d1-dirty: Sat Apr 17 07:39:42 CEST 2021 # pho@t2.osted.lan:/usr/src/sys/amd64/compile/PHO # db> [ `uname -p` != "amd64" ] && exit 0 . ../default.cfg cat > /tmp/syzkaller33.c < #include #include #include #include #include #include #include #include #include #include #include #include #include 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 < 5000) { continue; } kill_and_wait(pid, &status); break; } } } uint64_t r[1] = {0x0}; void execute_one(void) { intptr_t res = 0; res = syscall(SYS_ktimer_create, 0ul, 0ul, 0x200011c0ul); if (res != -1) r[0] = *(uint32_t*)0x200011c0; *(uint64_t*)0x20001200 = 0x800000000000000; *(uint64_t*)0x20001208 = 0; *(uint64_t*)0x20001210 = 0; *(uint64_t*)0x20001218 = 0xa2b; syscall(SYS_ktimer_settime, r[0], 1ul, 0x20001200ul, 0ul); } int main(void) { syscall(SYS_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x1012ul, -1, 0ul); loop(); return 0; } EOF mycc -o /tmp/syzkaller33 -Wall -Wextra -O0 /tmp/syzkaller33.c || exit 1 (cd /tmp; timeout 3m ./syzkaller33) rm -rf /tmp/syzkaller33 syzkaller33.c /tmp/syzkaller.* exit 0