X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Ffrontend_internal.h;fp=libringbuffer%2Ffrontend_internal.h;h=2f837f7d80134449816afcb3e97546bd311aea0e;hb=8fe67e2f0294bd2eeba46f88248daafd9838a5ad;hp=2d3b1071f9e4f10565ca52b0385c65359a8866f2;hpb=14459b487ebbd8e93c28f984eacefa315c157d2b;p=lttng-ust.git

diff --git a/libringbuffer/frontend_internal.h b/libringbuffer/frontend_internal.h
index 2d3b1071..2f837f7d 100644
--- a/libringbuffer/frontend_internal.h
+++ b/libringbuffer/frontend_internal.h
@@ -341,6 +341,12 @@ void lib_ring_buffer_check_deliver(const struct lttng_ust_lib_ring_buffer_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.
+		 */
+		cmm_smp_wmb();
 		if (caa_likely(v_cmpxchg(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
 					 old_commit_count, old_commit_count + 1)
 			   == old_commit_count)) {
@@ -386,6 +392,11 @@ void lib_ring_buffer_check_deliver(const struct lttng_ust_lib_ring_buffer_config
 			/* End of exclusive subbuffer access */
 			v_set(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
 			      commit_count);
+			/*
+			 * Order later updates to reserve count after
+			 * the commit cold cc_sb update.
+			 */
+			cmm_smp_wmb();
 			lib_ring_buffer_vmcore_check_deliver(config, buf,
 						 commit_count, idx, handle);