[Bug c/44554] Stack space after sigsetjmp is reused

["christian dot eggers at kathrein dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #1 from christian dot eggers at kathrein dot de  2010-06-16 07:17 -------
Created an attachment (id=20925)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20925&action=view)
Preprocessed source

compile with arm-linux-gnueabi-gcc -mcpu=arm920t -Os -o test.o -c test.i

This file is a stripped down version of the original source. Here __sigsetjmp
is used twice because pthread_cleanup_push()/pthread_cleanup_pop() are used
nested:

a = malloc();
pthread_cleanup_push(handler, a);
x = malloc() 
pthread_cleanup_push(handler, x)
...
pthread_cleanup_pop(1);
pthread_cleanup_pop(1);

The code is arranged in a way the the problem happens for both instances of
__cancel_arg are affected.

The bug is little bit "volatile", if you change the source it will usually
disappear or move to another position. For instance you may try removing the
marked line:

  comp_1 = 0.0;
  comp_2 = 0.0;
  for (i = 0; i < num_1 - delay1; ++i)
  {
-->   comp_1 += conj(comp_out[i]) * comp_out[i];
      comp_2 += conj(comp_out[i]) * comp_in[i];
  }

siglongjmp() is only used for demonstration purposes. You can also link with
"-pthreads -lm" to a full executable demo.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44554