test/pthread/tst-too-many-cleanups.c

   1 /*
   2  * This illustrates the bug where the cleanup function
   3  * of a thread may be called too many times.
   4  *
   5  * main thread:
   6  *  - grab mutex
   7  *  - spawn thread1
   8  *  - go to sleep
   9  * thread1:
  10  *  - register cleanup handler via pthread_cleanup_push()
  11  *  - try to grab mutex and sleep
  12  * main:
  13  *  - kill thread1
  14  *  - go to sleep
  15  * thread1 cleanup handler:
  16  *  - try to grab mutex and sleep
  17  * main:
  18  *  - kill thread1
  19  *  - go to sleep
  20  * thread1 cleanup handler:
  21  *  - wrongly called again
  22  */
  23
  24 #ifndef _GNU_SOURCE
  25 #define _GNU_SOURCE
  26 #endif
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <pthread.h>
  31 #include <assert.h>
  32 #include <unistd.h>
  33
  34 #define warn(fmt, args...) fprintf(stderr, "[%p] " fmt, (void*)pthread_self(), ## args)
  35 #define warnf(fmt, args...) warn("%s:%i: " fmt, __FUNCTION__, __LINE__, ## args)
  36
  37 int ok_to_kill_thread;
  38
  39 static void thread_killed(void *arg);
  40
  41 static void *KillMeThread(void *thread_par)
  42 {
  43         pthread_t pthread_id;
  44
  45         warnf("Starting child thread\n");
  46
  47         pthread_id = pthread_self();
  48         pthread_cleanup_push(thread_killed, (void *)pthread_id);
  49
  50         pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
  51         pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
  52
  53         /* main code */
  54         warnf("please kill me now\n");
  55         while (1) {
  56                 ok_to_kill_thread = 1;
  57                 sleep(1);
  58         }
  59
  60         pthread_cleanup_pop(0);
  61
  62         return 0;
  63 }
  64
  65 static void thread_killed(void *arg)
  66 {
  67         static int num_times_called = 0;
  68
  69         warnf("killing %p [cnt=%i]\n", arg, ++num_times_called);
  70         assert(num_times_called == 1);
  71
  72         /* pick any cancellation endpoint, sleep() will do just fine */
  73         while (1) {
  74                 warnf("sleeping in cancellation endpoint ...\n");
  75                 sleep(1);
  76         }
  77
  78         warnf("done cleaning up\n");
  79 }
  80
  81 int main(int argc, char *argv[])
  82 {
  83         int count = 3;
  84         pthread_t app_pthread_id;
  85
  86         /* need to tweak this test a bit to play nice with signals and LT */
  87         return 0;
  88
  89         ok_to_kill_thread = 0;
  90
  91         pthread_create(&app_pthread_id, NULL, KillMeThread, NULL);
  92
  93         warnf("waiting for thread to prepare itself\n");
  94         while (!ok_to_kill_thread)
  95                 sleep(1);
  96
  97         while (count--) {
  98                 warnf("killing thread\n");
  99                 pthread_cancel(app_pthread_id);
 100                 sleep(3);
 101         }
 102
 103         return 0;
 104 }