Bug 32922

Created attachment 53882 [details]
Fixes a bug in futex_wait() that causes timeouts to be ignored

I noticed after starting a program from an xterm and trying to put it in the
background that it would not resume. In kernel/futex.c line 1889 
restart->futex.flags needs FLAGS_HAS_TIMEOUT or the timeout gets ignored
after futex_wait() is interrupted by a signal.  The code below triggers it
on my Slackware64 13.1 system (glibc-2.11.1).

#include <stdio.h>
#include <pthread.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>

int main (void)
{
  pthread_condattr_t ca;
  pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER;
  pthread_cond_t cv;
  struct timespec ts;
  pid_t p;
  int i;

  if ( (p = fork()) != 0 )
    {
      printf("Child is running\n");
      sleep(3);
      kill(p, SIGSTOP);
      printf("Child is stopped\n");
      sleep(3);
      kill(p, SIGCONT);
      printf("Child should have resumed\n");
      sleep(3);
      kill(p, SIGINT);
      return 0;
    }

  pthread_condattr_init(&ca);
  pthread_condattr_setclock(&ca, CLOCK_MONOTONIC);
  pthread_cond_init(&cv, &ca);
  while(1)
    {
      clock_gettime(CLOCK_MONOTONIC, &ts);
      printf("SLEEP: %lu\n", ts.tv_sec);
      ts.tv_sec++;
      pthread_cond_timedwait(&cv, &mut, &ts);
      clock_gettime(CLOCK_MONOTONIC, &ts);
      printf("WAKE:  %lu\n", ts.tv_sec);
    }
  return 0;
}