| 1 | /* Copyright (c) 2015 PLUMgrid, http://plumgrid.com |
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| 2 | * |
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| 3 | * This program is free software; you can redistribute it and/or |
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| 4 | * modify it under the terms of version 2 of the GNU General Public |
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| 5 | * License as published by the Free Software Foundation. |
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| 6 | */ |
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| 7 | #include "vmlinux.h" |
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| 8 | #include <linux/version.h> |
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| 9 | #include <bpf/bpf_helpers.h> |
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| 10 | #include <bpf/bpf_tracing.h> |
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| 11 | |
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| 12 | struct pair { |
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| 13 | u64 val; |
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| 14 | u64 ip; |
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| 15 | }; |
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| 16 | |
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| 17 | struct { |
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| 18 | __uint(type, BPF_MAP_TYPE_HASH); |
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| 19 | __type(key, long); |
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| 20 | __type(value, struct pair); |
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| 21 | __uint(max_entries, 1000000); |
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| 22 | } my_map SEC(".maps" ); |
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| 23 | |
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| 24 | /* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe |
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| 25 | * example will no longer be meaningful |
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| 26 | */ |
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| 27 | SEC("kprobe/kmem_cache_free" ) |
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| 28 | int bpf_prog1(struct pt_regs *ctx) |
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| 29 | { |
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| 30 | long ptr = PT_REGS_PARM2(ctx); |
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| 31 | |
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| 32 | bpf_map_delete_elem(&my_map, &ptr); |
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| 33 | return 0; |
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| 34 | } |
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| 35 | |
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| 36 | SEC("kretprobe/kmem_cache_alloc_node_noprof" ) |
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| 37 | int bpf_prog2(struct pt_regs *ctx) |
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| 38 | { |
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| 39 | long ptr = PT_REGS_RC(ctx); |
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| 40 | long ip = 0; |
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| 41 | |
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| 42 | /* get ip address of kmem_cache_alloc_node_noprof() caller */ |
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| 43 | BPF_KRETPROBE_READ_RET_IP(ip, ctx); |
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| 44 | |
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| 45 | struct pair v = { |
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| 46 | .val = bpf_ktime_get_ns(), |
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| 47 | .ip = ip, |
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| 48 | }; |
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| 49 | |
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| 50 | bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY); |
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| 51 | return 0; |
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| 52 | } |
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| 53 | char _license[] SEC("license" ) = "GPL" ; |
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| 54 | u32 _version SEC("version" ) = LINUX_VERSION_CODE; |
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| 55 | |
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