X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Ffrontend_internal.h;h=ceb54e356a55d4bced2e8e976eb1a17417257d89;hb=a39fd8695a92480d6c27acc1ac013d344c91b927;hp=323a8df7f98cd7e5d3aba69302c6c291799b8bbd;hpb=e56bb47c3af00db3bc9e2dea711bef4882e6ef4c;p=lttng-ust.git

diff --git a/libringbuffer/frontend_internal.h b/libringbuffer/frontend_internal.h
index 323a8df7..ceb54e35 100644
--- a/libringbuffer/frontend_internal.h
+++ b/libringbuffer/frontend_internal.h
@@ -234,14 +234,11 @@ int lib_ring_buffer_reserve_committed(const struct lttng_ust_lib_ring_buffer_con
 				      struct lttng_ust_shm_handle *handle)
 {
 	unsigned long offset, idx, commit_count;
-	struct commit_counters_hot *cc_hot = shmp_index(handle, buf->commit_hot, idx);
+	struct commit_counters_hot *cc_hot;
 
 	CHAN_WARN_ON(chan, config->alloc != RING_BUFFER_ALLOC_PER_CPU);
 	CHAN_WARN_ON(chan, config->sync != RING_BUFFER_SYNC_PER_CPU);
 
-	if (caa_unlikely(!cc_hot))
-		return 0;
-
 	/*
 	 * Read offset and commit count in a loop so they are both read
 	 * atomically wrt interrupts. By deal with interrupt concurrency by
@@ -253,6 +250,9 @@ int lib_ring_buffer_reserve_committed(const struct lttng_ust_lib_ring_buffer_con
 	do {
 		offset = v_read(config, &buf->offset);
 		idx = subbuf_index(offset, chan);
+		cc_hot = shmp_index(handle, buf->commit_hot, idx);
+		if (caa_unlikely(!cc_hot))
+			return 0;
 		commit_count = v_read(config, &cc_hot->cc);
 	} while (offset != v_read(config, &buf->offset));