Attachment 1481354 Details for Bug 1626127 – malloc_nomem.c

malloc_nomem.c

malloc_nomem.c (text/plain), 1.87 KB, created by Paulo Andrade on 2018-09-06 15:55:28 UTC

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Creator: Paulo Andrade

Created: 2018-09-06 15:55:28 UTC

Size: 1.87 KB

patch

obsolete

>#include <stdlib.h>
>#include <string.h>
>#include <unistd.h>
>#include <pthread.h>
>#include <stdio.h>
>#include <assert.h>
>#include <sys/time.h>
>#include <sys/resource.h>
>
>/* gcc -O0 -std=c99 -m64 -o malloc_nomem malloc_nomem.c -lpthread */
>
>void* alloc_one_block(void* unused)
>{
>  void* result = malloc(sizeof(void*));
>  // Should be done with a condition variable but this is just a
>  // quick-and-dirty demo
>  sleep(1);
>  return result;
>}
>
>void* alloc_until_failure(void* arg)
>{
>  int blocks = 0;
>  while(malloc(sizeof(void*)))
>    {
>      ++blocks;
>    }
>  printf("%s thread allocated %d blocks before failure\n", (char*) arg, blocks);
>  return NULL;
>}
>
>int main(int argc, char* argv[])
>{
>  int arena_count = argc > 1 ? atoi(argv[1]) : 2;
>  pthread_t* threads = calloc(sizeof(pthread_t), arena_count);
>  for(int count = 0; count < arena_count; ++count)
>    {
>      pthread_t thread;
>      int result = pthread_create(threads + count, NULL, alloc_one_block, NULL);
>      assert(result == 0);
>    }
>  for(int count = 0; count < arena_count; ++count)
>    {
>      void* allocated;
>      int result = pthread_join(threads[count], &allocated);
>      assert(result == 0);
>      printf("Thread %d allocated block at %p\n", count, allocated);
>    }
>
>  struct rlimit limits;
>  limits.rlim_cur = 0;
>  limits.rlim_max = RLIM_INFINITY;
>  int result = setrlimit(RLIMIT_AS, &limits);
>  assert (result == 0);
>  printf("rlimit is now set\n");
>
>  alloc_until_failure("Main");
>
>  for(int count = 0; count < arena_count; ++count)
>    {
>      pthread_t thread;
>      int result = pthread_create(threads + count, NULL, alloc_until_failure, "Other");
>	  if(result != 0)
>	  {
>		  printf("pthread_create failed: %s\n", strerror(result));
>		  exit(1);
>	  }
>    }
>  for(int count = 0; count < arena_count; ++count)
>    {
>      void* allocated;
>      int result = pthread_join(threads[count], &allocated);
>      assert(result == 0);
>    }
>}

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