From: David van Moolenbroek <david@minix3.org>
Date: Fri, 5 Aug 2016 10:26:36 +0000 (+0000)
Subject: libmthread: resolve memory leaks on exception path
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/zpipe.c?a=commitdiff_plain;h=refs%2Fchanges%2F49%2F3349%2F1;p=minix.git

libmthread: resolve memory leaks on exception path

If libmthread runs into a memory allocation failure while attempting
to enlarge its thread pool, it does not free up any preliminary
allocations made so far.

Reported by dcb314.

This closes #152.

Change-Id: Ib882a4544e4802a0eb0a53446b43997876cde633
---

diff --git a/minix/lib/libmthread/allocate.c b/minix/lib/libmthread/allocate.c
index 9d2c45840..f34862aa6 100644
--- a/minix/lib/libmthread/allocate.c
+++ b/minix/lib/libmthread/allocate.c
@@ -194,12 +194,22 @@ static int mthread_increase_thread_pool(void)
   	new_tcb[i] = malloc(sizeof(mthread_tcb_t));
   	if (new_tcb[i] == NULL) {
   		mthread_debug("Can't allocate space for tcb");
+		/* Undo the allocations made so far. */
+		while (i-- > old_no_threads)
+			free(new_tcb[i]);
+		if (old_no_threads > 0) {
+			new_tcb = realloc(threads, old_no_threads *
+			    sizeof(mthread_tcb_t *));
+			if (new_tcb == NULL)
+				mthread_panic("Unable to shrink tcb array");
+		} else
+			free(new_tcb);
   		return(-1);
   	}
   	memset(new_tcb[i], '\0', sizeof(mthread_tcb_t)); /* Clear entry */
   }
 
-  /* We can breath again, let's tell the others about the good news */
+  /* We can breathe again, let's tell the others about the good news */
   threads = new_tcb; 
   no_threads = new_no_threads;