[patch] Accessing freed memory crash


check_selects calls a callback when there is an event on handle. The callback itself can remove the event with delete_select_channel --- when it happens, check_selects accesses defunct p->next pointer and crash may happen. (I reproduced crash on this when inserting sleep(1) somewhere in background-handling code to debug unrelated issues --- it is likely that the crash may happen normally too, but with small probability).

This is the fix:

--- key.c_      2006-08-11 01:49:19.000000000 +0200
+++ key.c       2006-08-11 01:49:31.000000000 +0200
@@ -185,9 +185,13 @@
     if (disabled_channels)

+    retry:
     for (p = select_list; p; p = p->next)
-       if (FD_ISSET (p->fd, select_set))
+       if (FD_ISSET (p->fd, select_set)) {
+           FD_CLR (p->fd, select_set);
            (*p->callback)(p->fd, p->info);
+           goto retry;
+       }

 void channels_down (void)


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]