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This patch adds a test exercising logic that was fixed / improved in
the previous patch in the series, as well as general sanity checking for
jit's PROBE_MEM logic which should've been unaffected by the previous
patch.
The added verifier test does the following:
* Acquire a referenced kptr to struct prog_test_ref_kfunc using
existing net/bpf/test_run.c kfunc
* Helper returns ptr to a specific prog_test_ref_kfunc whose first
two fields - both ints - have been prepopulated w/ vals 42 and
108, respectively
* kptr_xchg the acquired ptr into an arraymap
* Do a direct map_value load of the just-added ptr
* Goal of all this setup is to get an unreferenced kptr pointing to
struct with ints of known value, which is the result of this step
* Using unreferenced kptr obtained in previous step, do loads of
prog_test_ref_kfunc.a (offset 0) and .b (offset 4)
* Then incr the kptr by 8 and load prog_test_ref_kfunc.a again (this
time at offset -8)
* Add all the loaded ints together and return
Before the PROBE_MEM fixes in previous patch, the loads at offset 0 and
4 would succeed, while the load at offset -8 would incorrectly fail
runtime check emitted by the JIT and 0 out dst reg as a result. This
confirmed by retval of 150 for this test before previous patch - since
second .a read is 0'd out - and a retval of 192 with the fixed logic.
The test exercises the two optimizations to fixed logic added in last
patch as well:
* First load, with insn "r8 = *(u32 *)(r9 + 0)" exercises "insn->off
is 0, no need to add / sub from src_reg" optimization
* Third load, with insn "r9 = *(u32 *)(r9 - 8)" exercises "src_reg ==
dst_reg, no need to restore src_reg after load" optimization
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221216214319.3408356-2-davemarchevsky@fb.com
29 lines
760 B
C
29 lines
760 B
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
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#include <test_progs.h>
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#include <network_helpers.h>
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#include "jit_probe_mem.skel.h"
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void test_jit_probe_mem(void)
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{
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LIBBPF_OPTS(bpf_test_run_opts, opts,
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.data_in = &pkt_v4,
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.data_size_in = sizeof(pkt_v4),
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.repeat = 1,
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);
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struct jit_probe_mem *skel;
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int ret;
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skel = jit_probe_mem__open_and_load();
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if (!ASSERT_OK_PTR(skel, "jit_probe_mem__open_and_load"))
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return;
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ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_jit_probe_mem), &opts);
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ASSERT_OK(ret, "jit_probe_mem ret");
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ASSERT_OK(opts.retval, "jit_probe_mem opts.retval");
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ASSERT_EQ(skel->data->total_sum, 192, "jit_probe_mem total_sum");
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jit_probe_mem__destroy(skel);
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}
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