[dpdk-dev] [PATCH] mempool: Add sanity check when secondary link in less mempools than primary

[Jean Tourrilhes <jt@labs.hpe.com>]

mempool: Add sanity check when secondary link in less mempools than primary

If the primary and secondary process were build using different build
systems, the list of constructors included by the linker in each
binary might be different. Mempools are registered via constructors, so
the linker magic will directly impact which tailqs are registered with
the primary and the secondary.

DPDK currently assumes that the secondary has a superset of the
mempools registered at the primary, and they are in the same order
(same index in primary and secondary). In some build scenario, the
secondary might not initialise any mempools at all. This would result
in an obscure segfault when trying to use the mempool. Instead, fail
early with a more explicit error message.

Signed-off-by: Jean Tourrilhes <jt@labs.hpe.com>
---
 lib/librte_mempool/rte_mempool.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 2e28e2e..4fe9158 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -1275,6 +1275,16 @@ rte_mempool_lookup(const char *name)
 		return NULL;
 	}
 
+	/* Sanity check : secondary may have initialised less mempools
+	 * than primary due to linker and constructor magic. Note that
+	 * this does not address the case where the constructor order
+	 * is different between primary and secondary and where the index
+	 * points to the wrong ops. Jean II */
+	if(mp->ops_index >= (int32_t) rte_mempool_ops_table.num_ops) {
+		/* Do not dump mempool list, it will segfault. */
+		rte_panic("Cannot find ops for mempool, ops_index %d, num_ops %d - maybe due to build process or linker configuration\n", mp->ops_index, rte_mempool_ops_table.num_ops);
+	}
+
 	return mp;
 }