[lwip-users] infinite loop in sys_mbox_fetch

[E.F.Spijksma]

Hi,

I'm using freertos (since last week version 4.0.0) with the lwip stack 
demo, which I upgraded to 1.1.1.
I use the at91sam7x-ek develepmentboard. In the os I implemented EFSL so 
I could use a sd-card for the site.

My webserver got blocked everytime it got a timeout. When a timout 
occured there was een infinite loop in the function
sys_mbox_fetch(...) in the file sys.c checking the mbox for messages at 
the point goto again; . I fixed this at the moment by adding a counter 
on wich after a timeout occurs it will check the mbox 2 times for a 
message and then leave the function.
See below for source.

Regards
Edwin

void sys_mbox_fetch(sys_mbox_t mbox, void **msg)
{
    u32_t time;
    struct sys_timeouts *timeouts;
   struct sys_timeout *tmptimeout;
   sys_timeout_handler h;
   void *arg;
   u8_t iCounter = 0;


again:
   timeouts = sys_arch_timeouts();
  
   if (!timeouts || !timeouts->next)
   {
              
       sys_arch_mbox_fetch(mbox, msg, 0);
   }
   else
   {
      
       if (timeouts->next->time > 0)
       {
           time = sys_arch_mbox_fetch(mbox, msg, timeouts->next->time);
       }
       else
       {
           time = SYS_ARCH_TIMEOUT;
       }
  
       if (time == SYS_ARCH_TIMEOUT)
       {
         /* If time == SYS_ARCH_TIMEOUT, a timeout occured before a message
       could be fetched. We should now call the timeout handler and
       deallocate the memory allocated for the timeout. */
          
           tmptimeout = timeouts->next;
           timeouts->next = tmptimeout->next;
           h = tmptimeout->h;
           arg = tmptimeout->arg;
           memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
           if (h != NULL)
           {
               LWIP_DEBUGF(SYS_DEBUG, ("smf calling h=%p(%p)\n", (void 
*)h, (void *)arg));
               h(arg);
           }
           /* We try again to fetch a message from the mbox. */
           iCounter++;
           if(iCounter < 2)
               goto again;
       }
       else
       {
           /* If time != SYS_ARCH_TIMEOUT, a message was received 
before the timeout
           occured. The time variable is set to the number of
           milliseconds we waited for the message. */
           if (time <= timeouts->next->time)
           {
               timeouts->next->time -= time;
           }
           else
           {
               timeouts->next->time = 0;
           }
       }
   }
}