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author | Andrii Nakryiko <andrii@kernel.org> | 2022-04-04 16:42:01 -0700 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2022-04-05 13:16:08 -0700 |
commit | 630301b0d59dd85e43cca29382c459f9880af5f0 (patch) | |
tree | 91ff5442d921edd9026413e555e84f126f1a2373 /tools/testing/selftests/bpf/progs/test_usdt_multispec.c | |
parent | 4c59e584d1581b1bca143dda83d5c3e5baddbf20 (diff) | |
download | linux-630301b0d59dd85e43cca29382c459f9880af5f0.tar.bz2 |
selftests/bpf: Add basic USDT selftests
Add semaphore-based USDT to test_progs itself and write basic tests to
valicate both auto-attachment and manual attachment logic, as well as
BPF-side functionality.
Also add subtests to validate that libbpf properly deduplicates USDT
specs and handles spec overflow situations correctly, as well as proper
"rollback" of partially-attached multi-spec USDT.
BPF-side of selftest intentionally consists of two files to validate
that usdt.bpf.h header can be included from multiple source code files
that are subsequently linked into final BPF object file without causing
any symbol duplication or other issues. We are validating that __weak
maps and bpf_usdt_xxx() API functions defined in usdt.bpf.h do work as
intended.
USDT selftests utilize sys/sdt.h header that on Ubuntu systems comes
from systemtap-sdt-devel package. But to simplify everyone's life,
including CI but especially casual contributors to bpf/bpf-next that
are trying to build selftests, I've checked in sys/sdt.h header from [0]
directly. This way it will work on all architectures and distros without
having to figure it out for every relevant combination and adding any
extra implicit package dependencies.
[0] https://sourceware.org/git?p=systemtap.git;a=blob_plain;f=includes/sys/sdt.h;h=ca0162b4dc57520b96638c8ae79ad547eb1dd3a1;hb=HEAD
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20220404234202.331384-7-andrii@kernel.org
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_usdt_multispec.c')
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_usdt_multispec.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_usdt_multispec.c b/tools/testing/selftests/bpf/progs/test_usdt_multispec.c new file mode 100644 index 000000000000..3a090681f981 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_usdt_multispec.c @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/usdt.bpf.h> + +/* this file is linked together with test_usdt.c to validate that usdt.bpf.h + * can be included in multiple .bpf.c files forming single final BPF object + * file + */ + +extern int my_pid; + +int usdt_100_called; +int usdt_100_sum; + +SEC("usdt//proc/self/exe:test:usdt_100") +int BPF_USDT(usdt_100, int x) +{ + long tmp; + + if (my_pid != (bpf_get_current_pid_tgid() >> 32)) + return 0; + + __sync_fetch_and_add(&usdt_100_called, 1); + __sync_fetch_and_add(&usdt_100_sum, x); + + bpf_printk("X is %d, sum is %d", x, usdt_100_sum); + + return 0; +} + +char _license[] SEC("license") = "GPL"; |