[PATCH v2 5/5] eal: fix memzone fbarray cleanup

[Artemy Kovalyov]

The initialization of the Memzone file-backed array ensures its
uniqueness by employing an exclusive lock. This is crucial because only
one primary process can exist per specific shm_id, which is further
protected by the exclusive EAL runtime configuration lock.

However, during the process closure, the exclusive lock on both the
fbarray and the configuration is not explicitly released. The
responsibility of releasing these locks is left to the generic quit
procedure. This can lead to a potential race condition when the
configuration is released before the fbarray.

To address this, we propose explicitly closing the memzone fbarray. This
ensures proper order of operations during process closure and prevents
any potential race conditions arising from the mismatched lock release
timings.

Fixes: af75078fece3 ("first public release")
Cc: stable at dpdk.org

Signed-off-by: Artemy Kovalyov <artemyko at nvidia.com>
---
 lib/eal/common/eal_common_memzone.c | 12 ++++++++++++
 lib/eal/common/eal_private.h        |  5 +++++
 lib/eal/linux/eal.c                 |  1 +
 3 files changed, 18 insertions(+)

diff --git a/lib/eal/common/eal_common_memzone.c b/lib/eal/common/eal_common_memzone.c
index 1f3e701..7db8029 100644
--- a/lib/eal/common/eal_common_memzone.c
+++ b/lib/eal/common/eal_common_memzone.c
@@ -447,6 +447,18 @@
 	return ret;
 }
 
+void
+rte_eal_memzone_cleanup(void)
+{
+	struct rte_mem_config *mcfg;
+
+	mcfg = rte_eal_get_configuration()->mem_config;
+
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+		rte_fbarray_destroy(&mcfg->memzones);
+	}
+}
+
 /* Walk all reserved memory zones */
 void rte_memzone_walk(void (*func)(const struct rte_memzone *, void *),
 		      void *arg)
diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
index 4d2e806..944c365 100644
--- a/lib/eal/common/eal_private.h
+++ b/lib/eal/common/eal_private.h
@@ -81,6 +81,11 @@ struct rte_config {
 int rte_eal_memzone_init(void);
 
 /**
+ * Cleanup the memzone subsystem (private to eal).
+ */
+void rte_eal_memzone_cleanup(void);
+
+/**
  * Fill configuration with number of physical and logical processors
  *
  * This function is private to EAL.
diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
index 9b59cec..dfcbe64 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -1375,6 +1375,7 @@ static void rte_eal_init_alert(const char *msg)
 	eal_trace_fini();
 	eal_mp_dev_hotplug_cleanup();
 	rte_eal_alarm_cleanup();
+	rte_eal_memzone_cleanup();
 	/* after this point, any DPDK pointers will become dangling */
 	rte_eal_memory_detach();
 	rte_eal_malloc_heap_cleanup();
-- 
1.8.3.1