scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/samples/bpf/tracex4.bpf.c b/samples/bpf/tracex4.bpf.c
new file mode 100644
index 000000000..d786492fd
--- /dev/null
+++ b/samples/bpf/tracex4.bpf.c
@@ -0,0 +1,54 @@
+/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include "vmlinux.h"
+#include <linux/version.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+struct pair {
+	u64 val;
+	u64 ip;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, long);
+	__type(value, struct pair);
+	__uint(max_entries, 1000000);
+} my_map SEC(".maps");
+
+/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
+ * example will no longer be meaningful
+ */
+SEC("kprobe/kmem_cache_free")
+int bpf_prog1(struct pt_regs *ctx)
+{
+	long ptr = PT_REGS_PARM2(ctx);
+
+	bpf_map_delete_elem(&my_map, &ptr);
+	return 0;
+}
+
+SEC("kretprobe/kmem_cache_alloc_node_noprof")
+int bpf_prog2(struct pt_regs *ctx)
+{
+	long ptr = PT_REGS_RC(ctx);
+	long ip = 0;
+
+	/* get ip address of kmem_cache_alloc_node_noprof() caller */
+	BPF_KRETPROBE_READ_RET_IP(ip, ctx);
+
+	struct pair v = {
+		.val = bpf_ktime_get_ns(),
+		.ip = ip,
+	};
+
+	bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY);
+	return 0;
+}
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;