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, 47 insertions, 0 deletions

diff --git a/samples/bpf/tracex1.bpf.c b/samples/bpf/tracex1.bpf.c
new file mode 100644
index 000000000..ceedf0b1d
--- /dev/null
+++ b/samples/bpf/tracex1.bpf.c
@@ -0,0 +1,47 @@
+/* Copyright (c) 2013-2015 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 "net_shared.h"
+#include <linux/version.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+
+/* kprobe is NOT a stable ABI
+ * kernel functions can be removed, renamed or completely change semantics.
+ * Number of arguments and their positions can change, etc.
+ * In such case this bpf+kprobe example will no longer be meaningful
+ */
+SEC("kprobe.multi/__netif_receive_skb_core*")
+int bpf_prog1(struct pt_regs *ctx)
+{
+	/* attaches to kprobe __netif_receive_skb_core,
+	 * looks for packets on loopback device and prints them
+	 * (wildcard is used for avoiding symbol mismatch due to optimization)
+	 */
+	char devname[IFNAMSIZ];
+	struct net_device *dev;
+	struct sk_buff *skb;
+	int len;
+
+	bpf_core_read(&skb, sizeof(skb), (void *)PT_REGS_PARM1(ctx));
+	dev = BPF_CORE_READ(skb, dev);
+	len = BPF_CORE_READ(skb, len);
+
+	BPF_CORE_READ_STR_INTO(&devname, dev, name);
+
+	if (devname[0] == 'l' && devname[1] == 'o') {
+		char fmt[] = "skb %p len %d\n";
+		/* using bpf_trace_printk() for DEBUG ONLY */
+		bpf_trace_printk(fmt, sizeof(fmt), skb, len);
+	}
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;