audit: free module name

Reset the type of the record last as the helper `audit_free_module()`
depends on it.

    unreferenced object 0xffff888153b707f0 (size 16):
      comm "modprobe", pid 1319, jiffies 4295110033 (age 1083.016s)
      hex dump (first 16 bytes):
        62 69 6e 66 6d 74 5f 6d 69 73 63 00 6b 6b 6b a5  binfmt_misc.kkk.
      backtrace:
        [<ffffffffa07dbf9b>] kstrdup+0x2b/0x50
        [<ffffffffa04b0a9d>] __audit_log_kern_module+0x4d/0xf0
        [<ffffffffa03b6664>] load_module+0x9d4/0x2e10
        [<ffffffffa03b8f44>] __do_sys_finit_module+0x114/0x1b0
        [<ffffffffa1f47124>] do_syscall_64+0x34/0x80
        [<ffffffffa200007e>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Cc: stable@vger.kernel.org
Fixes: 12c5e81d ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

kernel/auditsc.c

@@ -1014,10 +1014,10 @@ static void audit_reset_context(struct audit_context *ctx)
 	ctx->target_comm[0] = '\0';
 	unroll_tree_refs(ctx, NULL, 0);
 	WARN_ON(!list_empty(&ctx->killed_trees));
-	ctx->type = 0;
 	audit_free_module(ctx);
 	ctx->fds[0] = -1;
 	audit_proctitle_free(ctx);
+	ctx->type = 0; /* reset last for audit_free_*() */
 }
 
 static inline struct audit_context *audit_alloc_context(enum audit_state state)