run error when use __weak to define function

HI,i want use __weak to define function and create a project like follow:

in file main.c

void weakFunctioin(void){

    logInfo("print nonWeakFunction\r\n");
    return;
}

int main(void){


    logInit(logLevelDebug);
    logInfo("Build @ %s %s,system start\r\n", __DATE__, __TIME__);

    weakFunctionTest(1);
    logInfo("Build @ %s %s,system stop\r\n", __DATE__, __TIME__);
    while(1);
    return 0;
}

in file weakTest.c

__weak void weakFunctioin(void){    //define as __weak
    logInfo("print weakFunction\r\n");
}

int weakFunctionTest(unsigned int tst){


    logInfo("print A\r\n");
    if (tst) {
        logInfo("print B\r\n");
        weakFunctioin();
        logInfo("print C\r\n");
    }else{
        logInfo("print D\r\n");
    }
    logInfo("print E\r\n");
    return 0;
}

and print as follow:
-I: Build @ Jun 12 2017 15:14:18,system start

-I: print A

-I: print B

-I: print nonWeakFunction

-I: print C

-I: print E

-I: Build @ Jun 12 2017 15:14:18,system stop

it run OK,BUT
when add a dead loop in __weak function in file weakTest.c like as

__weak void weakFunctioin(void){    //define as __weak
    logInfo("print weakFunction\r\n");
    while(1);
}

print as follow;
-I: Build @ Jun 12 2017 15:14:46,system start

-I: print A

-I: print B

-I: print nonWeakFunction

-I: print D //ERROR ERROR ERROR

-I: print E

-I: Build @ Jun 12 2017 15:14:46,system stop

it print "-I: print D" and like branch is error.
can anyone tell what's happen.
thx.

MDK-ARM version:5.21a
MCU: stm32L431RCT6
compiler cmd:--c99 -c --cpu Cortex-M4.fp -D__MICROLIB -g -O0 --apcs=interwork --split_sections
-IC:/Users/Administrator/Desktop/weakTest/RTE