Re: 2.6.10-rc2-mm1 - SELinux atomic_dec_and_test() bug

[James Morris]

Atomic underflow debugging in this kernel exposed a bug in the AVC RCU
code, fix below.  The effect of this bug would be delayed node
reclamation.

Signed-off-by: James Morris <jmorris@xxxxxxxxxx>

---

diff -purN -X dontdiff linux-2.6.10-rc2-mm1.o/security/selinux/avc.c linux-2.6.10-rc2-mm1.w/security/selinux/avc.c
--- linux-2.6.10-rc2-mm1.o/security/selinux/avc.c	2004-11-16 10:57:16.000000000 -0500
+++ linux-2.6.10-rc2-mm1.w/security/selinux/avc.c	2004-11-16 11:27:19.000000000 -0500
@@ -269,7 +269,7 @@ static inline int avc_reclaim_node(void)
 			continue;
 
 		list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
-			if (!atomic_dec_and_test(&node->ae.used)) {
+			if (atomic_dec_and_test(&node->ae.used)) {
 				/* Recently Unused */
 				avc_node_delete(node);
 				avc_cache_stats_incr(reclaims);

-
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