1720c42b90
Because test_bad_ret main program is not written in assembly, we don't
control instruction indices in timer_cb_ret_bad() subprog. This bites us
in timer/test_bad_ret subtest, where we see difference between cpuv4 and
other flavors.
For now, make __msg() expectations not rely on instruction indices by
anchoring them around bpf_get_prandom_u32 call. Once we have regex/glob
support for __msg(), this can be expressed a bit more nicely, but for
now just mitigating the problem with available means.
Fixes: e02dea158d ("selftests/bpf: validate async callback return value check correctness")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231208233028.3412690-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include <linux/bpf.h>
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#include <time.h>
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#include <errno.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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#include "bpf_tcp_helpers.h"
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char _license[] SEC("license") = "GPL";
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struct elem {
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struct bpf_timer t;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__type(key, int);
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__type(value, struct elem);
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} timer_map SEC(".maps");
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__naked __noinline __used
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static unsigned long timer_cb_ret_bad()
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{
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asm volatile (
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"call %[bpf_get_prandom_u32];"
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"if r0 s> 1000 goto 1f;"
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"r0 = 0;"
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"1:"
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"goto +0;" /* checkpoint */
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/* async callback is expected to return 0, so branch above
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* skipping r0 = 0; should lead to a failure, but if exit
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* instruction doesn't enforce r0's precision, this callback
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* will be successfully verified
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*/
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"exit;"
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:
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: __imm(bpf_get_prandom_u32)
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: __clobber_common
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);
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}
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SEC("fentry/bpf_fentry_test1")
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__log_level(2)
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__flag(BPF_F_TEST_STATE_FREQ)
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__failure
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/* check that fallthrough code path marks r0 as precise */
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__msg("mark_precise: frame0: regs=r0 stack= before")
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__msg(": (85) call bpf_get_prandom_u32#7") /* anchor message */
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/* check that branch code path marks r0 as precise */
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__msg("mark_precise: frame0: regs=r0 stack= before ") __msg(": (85) call bpf_get_prandom_u32#7")
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__msg("should have been in [0, 0]")
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long BPF_PROG2(test_bad_ret, int, a)
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{
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int key = 0;
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struct bpf_timer *timer;
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timer = bpf_map_lookup_elem(&timer_map, &key);
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if (timer) {
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bpf_timer_init(timer, &timer_map, CLOCK_BOOTTIME);
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bpf_timer_set_callback(timer, timer_cb_ret_bad);
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bpf_timer_start(timer, 1000, 0);
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}
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return 0;
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}
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