qemu-arm pthread汇编不可预测的行为

Question

我为qemu-arm编写了这个汇编代码来运行，有时它会给出分段错误，有时它会永远循环，我不知道为什么......

当我在线程函数中进行睡眠时，它似乎正在工作，否则就没有。

.data
msg_0:
    .ascii "enter thread\n"
    .align 2
msg_1:
    .ascii "exit thread\n"
    .align 2
msg_2:
    .ascii "created thread\n"
    .align 2

.text
.global main
.global f_conc
.global create_thread
f_conc:

    ldr r0, =msg_0
    bl puts
    mov r0, #0
    bl fflush   

    mov r0, #2
    #bl sleep

    ldr r0, =msg_1
    bl puts
    mov r0, #0
    bl fflush   

    mov r0, #0
    bl pthread_exit 
create_thread:
    push {lr}

    #reserve space
    mov r0, #4
    bl malloc

    mov r4, r0

    mov r1, #0
    ldr r2, =f_conc
    mov r3, #0
    bl pthread_create


    #ldr r0, =msg_2
    #bl puts

    mov r0, r4

    pop {pc}


main:
    push {lr}

    bl create_thread
    bl create_thread
    bl create_thread


    mov r0, #7
    #bl sleep

    mov r0, #0
    bl pthread_exit

    pop {pc}