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-rw-r--r--samples/bpf/tracex4_kern.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/samples/bpf/tracex4_kern.c b/samples/bpf/tracex4_kern.c
new file mode 100644
index 000000000..eb0f8fdd1
--- /dev/null
+++ b/samples/bpf/tracex4_kern.c
@@ -0,0 +1,55 @@
+/* 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 <linux/ptrace.h>
+#include <linux/version.h>
+#include <uapi/linux/bpf.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")
+int bpf_prog2(struct pt_regs *ctx)
+{
+ long ptr = PT_REGS_RC(ctx);
+ long ip = 0;
+
+ /* get ip address of kmem_cache_alloc_node() 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;