pthread_rwlock_wrlock are used inside real-time threads to cause hang to live, Why would you live?
03:16 22 Oct 2019

my problem:

  1. I create two threads, one real-time thread, one normal thread; both threads have read-write locks, and we bind two threads to one CPU core to run;
  2. Two threads will hang,Has anyone encountered such a problem?
  3. My Glibc library is libc-2.27.so
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#include 
#include 

pthread_rwlock_t qlock;


inline int set_cpu(int i)
{
    cpu_set_t mask;
    CPU_ZERO(&mask);

    CPU_SET(i,&mask);

    printf("thread %u, i = %d\n", pthread_self(), i);
    if(-1 == pthread_setaffinity_np(pthread_self() ,sizeof(mask),&mask))
    {
        fprintf(stderr, "pthread_setaffinity_np erro\n");
        return -1;
    }
    return 0;
}


int32_t set_rt_thread(const char *thread_name, uint32_t prio)
{
    struct sched_param cfg_param;
    int32_t ret = 0;

    if (prio > 99)
    {
        printf("%s rt prio is too big, %u.\n", thread_name, prio);
        return -EINVAL;
    }

    cfg_param.sched_priority = prio;
    ret = sched_setscheduler(0, SCHED_RR, &cfg_param);
    printf("Cur thread new scheduler = %d.\n", sched_getscheduler(0));
    if(ret < 0)
    {
        printf("%s sched_set scheduler to SCHED_RR error.\n", thread_name);
    }
    else
    {
        printf("%s tid=%ld is rt thread now.\n", thread_name, syscall(SYS_gettid));
    }

    return 0;
}

int32_t set_thread_name(const char *name)
strong text{
    return prctl(PR_SET_NAME, name);
}
//thread 1
void thead_input() {
        std::string thread_name = "thead_input";
        set_thread_name(thread_name.c_str());
        set_rt_thread(thread_name.c_str(),90);

        set_cpu(5);
        while(1) {
                pthread_rwlock_wrlock(&qlock);
                printf("thead 1\n");

                pthread_rwlock_unlock(&qlock);
                printf("thread unlock 2\n");
                usleep(100);
        }
}
//thread 2
void thead_output() {
        std::string thread_name = "thead_output";
        set_cpu(5);
        set_thread_name(thread_name.c_str());
        set_rt_thread(thread_name.c_str(),99);


        while(1) {
                pthread_rwlock_wrlock(&qlock);
                std::cout<<"thead 2"<

Debug log:

[Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/aarch64-linux-gnu/libthread_db.so.1".
0x0000007f899de31c in __GI___pthread_timedjoin_ex
(threadid=547765662160, thread_return=0x0, abstime=0x0,         block=) at pthread_join_common.c:89 89   pthread_join_common.c: No such file or directory. (gdb) thread     apply all bt

Thread 3 (Thread 0x7f88e0a1d0 (LWP 21439)):
#0  __pthread_rwlock_wrlock_full (abstime=0x0, rwlock=0x5577ff2020 ) at pthread_rwlock_common.c:679
#1  __GI___pthread_rwlock_wrlock (rwlock=0x5577ff2020 ) at pthread_rwlock_wrlock.c:27
#2  0x0000005577fdf8b8 in thead_output () at main.cpp:88
#3  0x0000005577fdff64 in std::__invoke_impl (__f=@0x55a376afc8: 0x5577fdf844 )
    at /usr/include/c++/7/bits/invoke.h:60
#4  0x0000005577fdfd30 in std::__invoke (__fn=@0x55a376afc8: 0x5577fdf844 )
    at /usr/include/c++/7/bits/invoke.h:95
#5  0x0000005577fe04cc in std::thread::_Invoker >::_M_invoke<0ul> (this=0x55a376afc8)
    at /usr/include/c++/7/thread:234
#6  0x0000005577fe0480 in std::thread::_Invoker >::operator() (this=0x55a376afc8)
    at /usr/include/c++/7/thread:243
#7  0x0000005577fe044c in std::thread::_State_impl> >::_M_run (this=0x55a376afc0)
    at /usr/include/c++/7/thread:186
#8  0x0000007f898fee14 in ?? () from /usr/lib/aarch64-linux-gnu/libstdc++.so.6
#9  0x0000007f899dd088 in start_thread (arg=0x7ff794cc5f) at pthread_create.c:463
#10 0x0000007f897964ec in thread_start () at ../sysdeps/unix/sysv/linux/aarch64/clone.S:78

Thread 2 (Thread 0x7f8960b1d0 (LWP 21438)):
#0  0x0000007f899e1ef8 in __pthread_rwlock_wrlock_full (abstime=0x0, rwlock=0x5577ff2020 )
    at pthread_rwlock_common.c:595
#1  __GI___pthread_rwlock_wrlock (rwlock=0x5577ff2020 ) at pthread_rwlock_wrlock.c:27
#2  0x0000005577fdf7ec in thead_input () at main.cpp:71
#3  0x0000005577fdff64 in std::__invoke_impl (__f=@0x55a376ae78: 0x5577fdf788 )
    at /usr/include/c++/7/bits/invoke.h:60
#4  0x0000005577fdfd30 in std::__invoke (__fn=@0x55a376ae78: 0x5577fdf788 )
    at /usr/include/c++/7/bits/invoke.h:95
#5  0x0000005577fe04cc in std::thread::_Invoker >::_M_invoke<0ul> (this=0x55a376ae78)
    at /usr/include/c++/7/thread:234
#6  0x0000005577fe0480 in std::thread::_Invoker >::operator() (this=0x55a376ae78)
    at /usr/include/c++/7/thread:243
#7  0x0000005577fe044c in std::thread::_State_impl> >::_M_run (this=0x55a376ae70) at /usr/include/c++/7/thread:186
#8  0x0000007f898fee14 in ?? () from /usr/lib/aarch64-linux-gnu/libstdc++.so.6
#9  0x0000007f899dd088 in start_thread (arg=0x7ff794cc5f) at pthread_create.c:463
#10 0x0000007f897964ec in thread_start () at ../sysdeps/unix/sysv/linux/aarch64/clone.S:78

Thread 1 (Thread 0x7f89a75ce0 (LWP 21436)):
#0  0x0000007f899de31c in __GI___pthread_timedjoin_ex (threadid=547765662160, thread_return=0x0, abstime=0x0, 
    block=) at pthread_join_common.c:89
#1  0x0000007f898ff0a8 in std::thread::join() () from /usr/lib/aarch64-linux-gnu/libstdc++.so.6
#2  0x0000005577fdf9cc in main (argc=1, argv=0x7ff794ce98) at main.cpp:104
c++11