[PATCH v2 2/2] lib/graph: default-align rte_graph_cluster_stats

[Marat Khalili <marat.khalili@huawei.com>]

This was flagged by undefined behaviour sanitizer: struct
rte_graph_cluster_stats is declared as `__rte_cache_aligned` but was
allocated using stdlib realloc which caused misaligned allocation. More
than one test needs to be executed in series in order to reproduce the
problem using graph_autotest, e.g:

    app/dpdk-test --no-huge --no-pci -m128 graph_autotest graph_autotest

First sanitizer message  (similar ones follow):

    lib/graph/graph_stats.c:209:13: runtime error: member access within
    misaligned address 0x606000008ea0 for type 'struct
    rte_graph_cluster_stats', which requires 64 byte alignment

To fix the issue remove `__rte_cache_aligned` attribute from struct
rte_graph_cluster_stats and struct rte_graph_cluster_node_stats that it
contains. There is no need to keep them cache-aligned since they are
only used in the slow path.

Fixes: af1ae8b6a32 ("graph: implement stats")

Signed-off-by: Marat Khalili <marat.khalili@huawei.com>
---

v2: Following the suggestions from Jerin Jacob changed the fix to simply
remove non-default alignment. Although there are many ways to make
alignment work, I personally agree that it is probably better to keep
the code simple as long as performance is not an issue.

Although reducing _actual_ alignment of allocated objects would probably
be a binary compatibility issue, here we are only changing _declared_
alignment to match the actual one, so it will more likely fix things
than break them.

devtools/test-meson-builds.sh completes successfully.

 lib/graph/graph_stats.c | 2 +-
 lib/graph/rte_graph.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/graph/graph_stats.c b/lib/graph/graph_stats.c
index 57cd72e7cc..4324717f33 100644
--- a/lib/graph/graph_stats.c
+++ b/lib/graph/graph_stats.c
@@ -29,7 +29,7 @@ struct cluster_node {
 	struct rte_node *nodes[];
 };
 
-struct __rte_cache_aligned rte_graph_cluster_stats {
+struct rte_graph_cluster_stats {
 	/* Header */
 	rte_graph_cluster_stats_cb_t fn;
 	uint32_t cluster_node_size; /* Size of struct cluster_node */
diff --git a/lib/graph/rte_graph.h b/lib/graph/rte_graph.h
index 097d0dc9d5..826204cad9 100644
--- a/lib/graph/rte_graph.h
+++ b/lib/graph/rte_graph.h
@@ -202,7 +202,7 @@ struct rte_graph_cluster_stats_param {
  *
  * @see struct rte_graph_cluster_stats_param::fn
  */
-struct __rte_cache_aligned rte_graph_cluster_node_stats {
+struct rte_graph_cluster_node_stats {
 	uint64_t ts;	    /**< Current timestamp. */
 	uint64_t calls;	    /**< Current number of calls made. */
 	uint64_t objs;      /**< Current number of objs processed. */
-- 
2.43.0