[Bug] pthread_cancel线程无法退出

RT-Thread Version

c9c103f30e28b31e5d393e7a8cc1a07779fb99dc

Hardware Type/Architectures

risc-v c908

Develop Toolchain

GCC

Describe the bug

调用pthread_cancel线程无法退出，附上测试代码

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <pthread.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>

pthread_t tid;

static void *subthread(void *arg)
{
    while (1) {
        usleep(1000000);
        printf("%s: %d\n", __func__, __LINE__);
    }

    return 0;
}

int main(int argc, char **argv)
{
    pthread_create(&tid, NULL, subthread, 0);

    while (getchar() != 'q')
        usleep(10000);

    printf("%s: %d\n", __func__, __LINE__);
    pthread_cancel(tid);
    printf("%s: %d\n", __func__, __LINE__);
    pthread_join(tid, NULL);
    printf("%s: %d\n", __func__, __LINE__);

    return 0;
}

Other additional context

No response

Reproduce the report on the stated RISC-V C908 target with GCC using the provided pthread_create, pthread_cancel, and pthread_join program. Start by locating the implementations of pthread_cancel and pthread_join, then trace how cancellation interacts with the thread blocked in usleep. Done means the cancelled thread exits and pthread_join completes as expected.