glusterfsd/cleanup: Protect graph object under a lock

While processing a cleanup_and_exit function, we are
accessing a graph object. But this has not been protected
under a lock. Because a parallel cleanup of a graph is quite
possible which might lead to an invalid memory access

Change-Id: Id05ca70d5b57e172b0401d07b6a1f5386c044e79
fixes: bz#1708926
Signed-off-by: Mohammed Rafi KC <rkavunga@redhat.com>

1 files changed, 13 insertions, 3 deletions

diff --git a/libglusterfs/src/statedump.c b/libglusterfs/src/statedump.c
index 04a7e18ef3b..7426b91a156 100644
--- a/libglusterfs/src/statedump.c
+++ b/libglusterfs/src/statedump.c
@@ -807,11 +807,17 @@ gf_proc_dump_info(int signum, glusterfs_ctx_t *ctx)
 
     gf_msg_trace("dump", 0, "received statedump request (sig:USR1)");
 
-    gf_proc_dump_lock();
-
     if (!ctx)
         goto out;
 
+    /*
+     * Multiplexed daemons can change the active graph when attach/detach
+     * is called. So this has to be protected with the cleanup lock.
+     */
+    if (mgmt_is_multiplexed_daemon(ctx->cmd_args.process_name))
+        pthread_mutex_lock(&ctx->cleanup_lock);
+    gf_proc_dump_lock();
+
     if (!mgmt_is_multiplexed_daemon(ctx->cmd_args.process_name) &&
         (ctx && ctx->active)) {
         top = ctx->active->first;
@@ -925,7 +931,11 @@ gf_proc_dump_info(int signum, glusterfs_ctx_t *ctx)
 out:
     GF_FREE(dump_options.dump_path);
     dump_options.dump_path = NULL;
-    gf_proc_dump_unlock();
+    if (ctx) {
+        gf_proc_dump_unlock();
+        if (mgmt_is_multiplexed_daemon(ctx->cmd_args.process_name))
+            pthread_mutex_unlock(&ctx->cleanup_lock);
+    }
 
     return;
 }