c++ pthreads - 在尝试锁定互斥锁以进行读取时崩溃

Question

类 LocalT 有其他类的成员实现了 read-write-mutex。 Mutex 在构造函数中初始化，并使用 pthread_rwlock_rdlock(&aMutex); 进行读取锁定。所以，看起来，互斥类没问题。但是，当某些 LocalT 对象锁定其互斥成员以供读取时，程序崩溃了。

CSerialize.cpp:2054 行是 MUTEX.lock_reading();

Thread 6 (Thread 0x80d4e00 (runnable)):
#0  0x4864f11d in pthread_mutex_lock () from /lib/libpthread.so.2
#1  0x4864b558 in pthread_rwlock_init () from /lib/libpthread.so.2
#2  0x4864b659 in pthread_rwlock_rdlock () from /lib/libpthread.so.2
#3  0x0807ae14 in LocalT::serialize (this=0x80d4e00, outbin=@0x7574736b)
    at CSerialize.cpp:2054

另外两个正在运行的线程:

1) 在套接字accept();

2) popen() 调用的下一个可运行线程，似乎是从管道执行或读取。但是不知道什么是 __error() ??????

Thread 1 (Thread 0x8614800 (LWP 100343)):
#0  0x4865b8f9 in __error () from /lib/libpthread.so.2
#1  0x4865a15a in pthread_testcancel () from /lib/libpthread.so.2
#2  0x486425bf in read () from /lib/libpthread.so.2
#3  0x08056340 in UT::execute_popen (command=@0x4865e6bc,
    ptr_output=0xbf2f7d30) at Utils.cpp:75

3) 所有其他线程休眠。

我不知道它为什么会崩溃？也许有人可以假设或提出建议？

==编辑==

这是一个系统(？)线程(我没有创建它，但程序总是有 +1 个线程)。它总是:

Thread 8 (Thread 0x80d4a00 (LWP 100051)):
#0  0x4865a79b in pthread_testcancel () from /lib/libpthread.so.2
#1  0x48652412 in pthread_mutexattr_init () from /lib/libpthread.so.2
#2  0x489fd450 in ?? ()

==EDIT2 - bt 根据要求==

(gdb) bt
#0  0x4865a7db in pthread_testcancel () from /lib/libpthread.so.2
#1  0x48652412 in pthread_mutexattr_init () from /lib/libpthread.so.2
#2  0x489fd450 in ?? ()

奇怪的是……为什么 ？？ () ?

==EDIT3 - 加载核心时==

Program terminated with signal 11, Segmentation fault.
[skiped]
#0  0x4865a7db in pthread_testcancel () from /lib/libpthread.so.2
[New Thread 0x8614800 (LWP 100343)]
[New Thread 0x8614600 (sleeping)]
[New Thread 0x8614400 (sleeping)]
[New Thread 0x8614200 (sleeping)]
[New Thread 0x8614000 (sleeping)]
[New Thread 0x80d4e00 (runnable)]
[New Thread 0x80d4c00 (sleeping)]
[New Thread 0x80d4a00 (LWP 100051)]
[New Thread 0x80d4000 (runnable)]
[New LWP 100802]

(gdb) info thread
* 10 LWP 100802  0x4865a7db in pthread_testcancel () from /lib/libpthread.so.2
  9 Thread 0x80d4000 (runnable)  0x486d7bd3 in accept () from /lib/libc.so.6 -- MAIN() THREAD
  8 Thread 0x80d4a00 (LWP 100051)  0x4865a79b in pthread_testcancel ()
   from /lib/libpthread.so.2 ( UNIDENTIFIED THREAD system()? ) 
  7 Thread 0x80d4c00 (sleeping)  0x48651cb6 in pthread_mutexattr_init ()
   from /lib/libpthread.so.2 (SIGNAL PROCESSOR THREAD)
  6 Thread 0x80d4e00 (runnable)  0x4864f11d in pthread_mutex_lock ()
   from /lib/libpthread.so.2 (MAINTENANCE THREAD)
  5 Thread 0x8614000 (sleeping)  0x48651cb6 in pthread_mutexattr_init ()
   from /lib/libpthread.so.2 (other mutex cond_wait - worker 1)
  4 Thread 0x8614200 (sleeping)  0x48651cb6 in pthread_mutexattr_init ()
   from /lib/libpthread.so.2 (other mutex cond_wait - worker 2 )
  3 Thread 0x8614400 (sleeping)  0x48651cb6 in pthread_mutexattr_init ()
   from /lib/libpthread.so.2 (other mutex cond_wait - worker 3 )
  2 Thread 0x8614600 (sleeping)  0x48651cb6 in pthread_mutexattr_init ()
   from /lib/libpthread.so.2 (other mutex cond_wait - worker 4)
  1 Thread 0x8614800 (LWP 100343)  0x4865b8f9 in __error ()
   from /lib/libpthread.so.2 ( popen() thread see below)

我创建了:1 个维护线程(序列化)、1 个 popen() 线程、4 个工作线程、1 个主线程、1 个信号线程 = 8 个线程....

Answer 1

您称为系统线程的线程实际上是您程序的主线程。

其次，根据您目前分享的信息，您似乎正在获取互斥量但从未释放它。这会导致不稳定的状态(某些参数具有错误的值)，从而导致崩溃。我相信您也会观察到间歇性挂起。

当它崩溃时，你能分享 backtrace 吗？