X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Ffrontend_internal.h;fp=lib%2Fringbuffer%2Ffrontend_internal.h;h=dbebdeec86f3362c30d59642ef9ab6910ca94a28;hb=0348b08949345b263015bb95bcaae8f7a607fb77;hp=bc284333f64c505e6e3fca646248073a8927f306;hpb=43b690e5e7b2b58166722a478767703886e91aaa;p=lttng-modules.git

diff --git a/lib/ringbuffer/frontend_internal.h b/lib/ringbuffer/frontend_internal.h
index bc284333..dbebdeec 100644
--- a/lib/ringbuffer/frontend_internal.h
+++ b/lib/ringbuffer/frontend_internal.h
@@ -331,6 +331,12 @@ void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
 		 * The subbuffer size is least 2 bytes (minimum size: 1 page).
 		 * This guarantees that old_commit_count + 1 != commit_count.
 		 */
+
+		/*
+		 * Order prior updates to reserve count prior to the
+		 * commit_cold cc_sb update.
+		 */
+		smp_wmb();
 		if (likely(v_cmpxchg(config, &buf->commit_cold[idx].cc_sb,
 					 old_commit_count, old_commit_count + 1)
 			   == old_commit_count)) {
@@ -373,6 +379,11 @@ void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
 			/* End of exclusive subbuffer access */
 			v_set(config, &buf->commit_cold[idx].cc_sb,
 			      commit_count);
+			/*
+			 * Order later updates to reserve count after
+			 * the commit_cold cc_sb update.
+			 */
+			smp_wmb();
 			lib_ring_buffer_vmcore_check_deliver(config, buf,
 							 commit_count, idx);