selftests: bpf: test writable buffers in raw tps
This tests that:
* a BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE cannot be attached if it
uses either:
* a variable offset to the tracepoint buffer, or
* an offset beyond the size of the tracepoint buffer
* a tracer can modify the buffer provided when attached to a writable
tracepoint in bpf_prog_test_run
Signed-off-by: Matt Mullins <mmullins@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Matt Mullins
Alexei Starovoitov
parent
4635b0ae4d
commit
e950e84336
50
include/trace/events/bpf_test_run.h
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50
include/trace/events/bpf_test_run.h
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@ -0,0 +1,50 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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#undef TRACE_SYSTEM
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#define TRACE_SYSTEM bpf_test_run
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#if !defined(_TRACE_BPF_TEST_RUN_H) || defined(TRACE_HEADER_MULTI_READ)
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#define _TRACE_BPF_TEST_RUN_H
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#include <linux/tracepoint.h>
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DECLARE_EVENT_CLASS(bpf_test_finish,
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TP_PROTO(int *err),
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TP_ARGS(err),
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TP_STRUCT__entry(
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__field(int, err)
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),
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TP_fast_assign(
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__entry->err = *err;
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),
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TP_printk("bpf_test_finish with err=%d", __entry->err)
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);
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#ifdef DEFINE_EVENT_WRITABLE
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#undef BPF_TEST_RUN_DEFINE_EVENT
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#define BPF_TEST_RUN_DEFINE_EVENT(template, call, proto, args, size) \
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DEFINE_EVENT_WRITABLE(template, call, PARAMS(proto), \
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PARAMS(args), size)
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#else
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#undef BPF_TEST_RUN_DEFINE_EVENT
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#define BPF_TEST_RUN_DEFINE_EVENT(template, call, proto, args, size) \
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DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args))
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#endif
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BPF_TEST_RUN_DEFINE_EVENT(bpf_test_finish, bpf_test_finish,
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TP_PROTO(int *err),
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TP_ARGS(err),
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sizeof(int)
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);
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#endif
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/* This part must be outside protection */
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#include <trace/define_trace.h>
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@ -13,6 +13,9 @@
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#include <net/sock.h>
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#include <net/tcp.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/bpf_test_run.h>
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static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat,
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u32 *retval, u32 *time)
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{
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@ -100,6 +103,7 @@ static int bpf_test_finish(const union bpf_attr *kattr,
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if (err != -ENOSPC)
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err = 0;
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out:
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trace_bpf_test_finish(&err);
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return err;
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}
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@ -0,0 +1,42 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <test_progs.h>
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#include <linux/nbd.h>
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void test_raw_tp_writable_reject_nbd_invalid(void)
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{
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__u32 duration = 0;
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char error[4096];
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int bpf_fd = -1, tp_fd = -1;
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const struct bpf_insn program[] = {
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/* r6 is our tp buffer */
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BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
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/* one byte beyond the end of the nbd_request struct */
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BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_6,
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sizeof(struct nbd_request)),
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BPF_EXIT_INSN(),
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};
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struct bpf_load_program_attr load_attr = {
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.prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
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.license = "GPL v2",
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.insns = program,
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.insns_cnt = sizeof(program) / sizeof(struct bpf_insn),
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.log_level = 2,
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};
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bpf_fd = bpf_load_program_xattr(&load_attr, error, sizeof(error));
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if (CHECK(bpf_fd < 0, "bpf_raw_tracepoint_writable load",
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"failed: %d errno %d\n", bpf_fd, errno))
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return;
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tp_fd = bpf_raw_tracepoint_open("nbd_send_request", bpf_fd);
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if (CHECK(tp_fd >= 0, "bpf_raw_tracepoint_writable open",
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"erroneously succeeded\n"))
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goto out_bpffd;
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close(tp_fd);
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out_bpffd:
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close(bpf_fd);
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}
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@ -0,0 +1,80 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <test_progs.h>
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#include <linux/nbd.h>
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void test_raw_tp_writable_test_run(void)
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{
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__u32 duration = 0;
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char error[4096];
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const struct bpf_insn trace_program[] = {
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BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6, 0),
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BPF_MOV64_IMM(BPF_REG_0, 42),
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BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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struct bpf_load_program_attr load_attr = {
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.prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
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.license = "GPL v2",
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.insns = trace_program,
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.insns_cnt = sizeof(trace_program) / sizeof(struct bpf_insn),
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.log_level = 2,
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};
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int bpf_fd = bpf_load_program_xattr(&load_attr, error, sizeof(error));
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if (CHECK(bpf_fd < 0, "bpf_raw_tracepoint_writable loaded",
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"failed: %d errno %d\n", bpf_fd, errno))
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return;
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const struct bpf_insn skb_program[] = {
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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struct bpf_load_program_attr skb_load_attr = {
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.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
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.license = "GPL v2",
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.insns = skb_program,
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.insns_cnt = sizeof(skb_program) / sizeof(struct bpf_insn),
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};
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int filter_fd =
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bpf_load_program_xattr(&skb_load_attr, error, sizeof(error));
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if (CHECK(filter_fd < 0, "test_program_loaded", "failed: %d errno %d\n",
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filter_fd, errno))
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goto out_bpffd;
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int tp_fd = bpf_raw_tracepoint_open("bpf_test_finish", bpf_fd);
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if (CHECK(tp_fd < 0, "bpf_raw_tracepoint_writable opened",
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"failed: %d errno %d\n", tp_fd, errno))
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goto out_filterfd;
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char test_skb[128] = {
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0,
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};
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__u32 prog_ret;
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int err = bpf_prog_test_run(filter_fd, 1, test_skb, sizeof(test_skb), 0,
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0, &prog_ret, 0);
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CHECK(err != 42, "test_run",
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"tracepoint did not modify return value\n");
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CHECK(prog_ret != 0, "test_run_ret",
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"socket_filter did not return 0\n");
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close(tp_fd);
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err = bpf_prog_test_run(filter_fd, 1, test_skb, sizeof(test_skb), 0, 0,
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&prog_ret, 0);
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CHECK(err != 0, "test_run_notrace",
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"test_run failed with %d errno %d\n", err, errno);
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CHECK(prog_ret != 0, "test_run_ret_notrace",
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"socket_filter did not return 0\n");
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out_filterfd:
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close(filter_fd);
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out_bpffd:
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close(bpf_fd);
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}
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34
tools/testing/selftests/bpf/verifier/raw_tp_writable.c
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34
tools/testing/selftests/bpf/verifier/raw_tp_writable.c
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@ -0,0 +1,34 @@
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{
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"raw_tracepoint_writable: reject variable offset",
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.insns = {
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/* r6 is our tp buffer */
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BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
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BPF_LD_MAP_FD(BPF_REG_1, 0),
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/* move the key (== 0) to r10-8 */
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BPF_MOV32_IMM(BPF_REG_0, 0),
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BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
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BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
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/* lookup in the map */
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
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BPF_FUNC_map_lookup_elem),
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/* exit clean if null */
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BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
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BPF_EXIT_INSN(),
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/* shift the buffer pointer to a variable location */
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0),
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BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_0),
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/* clobber whatever's there */
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BPF_MOV64_IMM(BPF_REG_7, 4242),
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BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_7, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.fixup_map_hash_8b = { 1, },
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.prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
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.errstr = "R6 invalid variable buffer offset: off=0, var_off=(0x0; 0xffffffff)",
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},
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