linux.git/tools/testing/selftests/bpf/Makefile, branch v6.9 Linux kernel source tree selftests/bpf: Extend uprobe/uretprobe triggering benchmarks 2024-03-04T13:40:24+00:00 Andrii Nakryiko andrii@kernel.org 2024-03-01T21:45:51+00:00 8f79870ec8a9409983ad5981e1b7d599cbf047bd Settle on three "flavors" of uprobe/uretprobe, installed on different kinds of instruction: nop, push, and ret. All three are testing different internal code paths emulating or single-stepping instructions, so are interesting to compare and benchmark separately. To ensure `push rbp` instruction we ensure that uprobe_target_push() is not a leaf function by calling (global __weak) noop function and returning something afterwards (if we don't do that, compiler will just do a tail call optimization). Also, we need to make sure that compiler isn't skipping frame pointer generation, so let's add `-fno-omit-frame-pointers` to Makefile. Just to give an idea of where we currently stand in terms of relative performance of different uprobe/uretprobe cases vs a cheap syscall (getpgid()) baseline, here are results from my local machine: $ benchs/run_bench_uprobes.sh base : 1.561 ± 0.020M/s uprobe-nop : 0.947 ± 0.007M/s uprobe-push : 0.951 ± 0.004M/s uprobe-ret : 0.443 ± 0.007M/s uretprobe-nop : 0.471 ± 0.013M/s uretprobe-push : 0.483 ± 0.004M/s uretprobe-ret : 0.306 ± 0.007M/s Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240301214551.1686095-1-andrii@kernel.org 
Settle on three "flavors" of uprobe/uretprobe, installed on different
kinds of instruction: nop, push, and ret. All three are testing
different internal code paths emulating or single-stepping instructions,
so are interesting to compare and benchmark separately.

To ensure `push rbp` instruction we ensure that uprobe_target_push() is
not a leaf function by calling (global __weak) noop function and
returning something afterwards (if we don't do that, compiler will just
do a tail call optimization).

Also, we need to make sure that compiler isn't skipping frame pointer
generation, so let's add `-fno-omit-frame-pointers` to Makefile.

Just to give an idea of where we currently stand in terms of relative
performance of different uprobe/uretprobe cases vs a cheap syscall
(getpgid()) baseline, here are results from my local machine:

$ benchs/run_bench_uprobes.sh
base           :    1.561 ± 0.020M/s
uprobe-nop     :    0.947 ± 0.007M/s
uprobe-push    :    0.951 ± 0.004M/s
uprobe-ret     :    0.443 ± 0.007M/s
uretprobe-nop  :    0.471 ± 0.013M/s
uretprobe-push :    0.483 ± 0.004M/s
uretprobe-ret  :    0.306 ± 0.007M/s

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240301214551.1686095-1-andrii@kernel.org
selftests/bpf: Test case for lacking CFI stub functions. 2024-02-22T20:26:41+00:00 Kui-Feng Lee thinker.li@gmail.com 2024-02-22T02:11:05+00:00 e9bbda13a7b876451285ab15fb600b809e5e2290 Ensure struct_ops rejects the registration of struct_ops types without proper CFI stub functions. bpf_test_no_cfi.ko is a module that attempts to register a struct_ops type called "bpf_test_no_cfi_ops" with cfi_stubs of NULL and non-NULL value. The NULL one should fail, and the non-NULL one should succeed. The module can only be loaded successfully if these registrations yield the expected results. Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com> Link: https://lore.kernel.org/r/20240222021105.1180475-3-thinker.li@gmail.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> 
Ensure struct_ops rejects the registration of struct_ops types without
proper CFI stub functions.

bpf_test_no_cfi.ko is a module that attempts to register a struct_ops type
called "bpf_test_no_cfi_ops" with cfi_stubs of NULL and non-NULL value.
The NULL one should fail, and the non-NULL one should succeed. The module
can only be loaded successfully if these registrations yield the expected
results.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240222021105.1180475-3-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
selftests/bpf: Remove intermediate test files. 2024-02-21T21:49:14+00:00 Alexei Starovoitov ast@kernel.org 2024-02-20T23:11:02+00:00 01dbd7d8720a0cc97dad5e70ec674dacdc66cf3c The test of linking process creates several intermediate files. Remove them once the build is over. This reduces the number of files in selftests/bpf/ directory from ~4400 to ~2600. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240220231102.49090-1-alexei.starovoitov@gmail.com 
The test of linking process creates several intermediate files.
Remove them once the build is over.

This reduces the number of files in selftests/bpf/ directory
from ~4400 to ~2600.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240220231102.49090-1-alexei.starovoitov@gmail.com
selftests/bpf: Remove empty TEST_CUSTOM_PROGS 2024-02-16T17:08:26+00:00 Marcos Paulo de Souza mpdesouza@suse.com 2024-02-16T12:42:45+00:00 7648f0c91eaa3598add9e91991a5483b29da32ee Commit f04a32b2c5b5 ("selftests/bpf: Do not use sign-file as testcase") removed the TEST_CUSTOM_PROGS assignment, and removed it from being used on TEST_GEN_FILES. Remove two leftovers from that cleanup. Found by inspection. Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexey Gladkov <legion@kernel.org> Link: https://lore.kernel.org/bpf/20240216-bpf-selftests-custom-progs-v1-1-f7cf281a1fda@suse.com 
Commit f04a32b2c5b5 ("selftests/bpf: Do not use sign-file as testcase")
removed the TEST_CUSTOM_PROGS assignment, and removed it from being used
on TEST_GEN_FILES. Remove two leftovers from that cleanup. Found by
inspection.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexey Gladkov <legion@kernel.org>
Link: https://lore.kernel.org/bpf/20240216-bpf-selftests-custom-progs-v1-1-f7cf281a1fda@suse.com
bpf: Move -Wno-compare-distinct-pointer-types to BPF_CFLAGS 2024-01-30T15:13:40+00:00 Jose E. Marchesi jose.marchesi@oracle.com 2024-01-30T11:36:24+00:00 24219056805f3988bf93e494499b2329453fc706 Clang supports enabling/disabling certain conversion diagnostics via the -W[no-]compare-distinct-pointer-types command line options. Disabling this warning is required by some BPF selftests due to -Werror. Until very recently GCC would emit these warnings unconditionally, which was a problem for gcc-bpf, but we added support for the command-line options to GCC upstream [1]. This patch moves the -Wno-cmopare-distinct-pointer-types from CLANG_CFLAGS to BPF_CFLAGS in selftests/bpf/Makefile so the option is also used in gcc-bpf builds, not just in clang builds. Tested in bpf-next master. No regressions. [1] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/627769.html Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240130113624.24940-1-jose.marchesi@oracle.com 
Clang supports enabling/disabling certain conversion diagnostics via
the -W[no-]compare-distinct-pointer-types command line options.
Disabling this warning is required by some BPF selftests due to
-Werror.  Until very recently GCC would emit these warnings
unconditionally, which was a problem for gcc-bpf, but we added support
for the command-line options to GCC upstream [1].

This patch moves the -Wno-cmopare-distinct-pointer-types from
CLANG_CFLAGS to BPF_CFLAGS in selftests/bpf/Makefile so the option
is also used in gcc-bpf builds, not just in clang builds.

Tested in bpf-next master.
No regressions.

  [1] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/627769.html

Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240130113624.24940-1-jose.marchesi@oracle.com
bpf: Build type-punning BPF selftests with -fno-strict-aliasing 2024-01-30T15:08:18+00:00 Jose E. Marchesi jose.marchesi@oracle.com 2024-01-30T11:03:43+00:00 27a90b14b93d3b2e1efd10764e456af7e2a42991 A few BPF selftests perform type punning and they may break strict aliasing rules, which are exploited by both GCC and clang by default while optimizing. This can lead to broken compiled programs. This patch disables strict aliasing for these particular tests, by mean of the -fno-strict-aliasing command line option. This will make sure these tests are optimized properly even if some strict aliasing rule gets violated. After this patch, GCC is able to build all the selftests without warning about potential strict aliasing issue. bpf@vger discussion on strict aliasing and BPF selftests: https://lore.kernel.org/bpf/bae1205a-b6e5-4e46-8e20-520d7c327f7a@linux.dev/T/#t Tested in bpf-next master. No regressions. Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/bae1205a-b6e5-4e46-8e20-520d7c327f7a@linux.dev Link: https://lore.kernel.org/bpf/20240130110343.11217-1-jose.marchesi@oracle.com 
A few BPF selftests perform type punning and they may break strict
aliasing rules, which are exploited by both GCC and clang by default
while optimizing.  This can lead to broken compiled programs.

This patch disables strict aliasing for these particular tests, by
mean of the -fno-strict-aliasing command line option.  This will make
sure these tests are optimized properly even if some strict aliasing
rule gets violated.

After this patch, GCC is able to build all the selftests without
warning about potential strict aliasing issue.

bpf@vger discussion on strict aliasing and BPF selftests:
https://lore.kernel.org/bpf/bae1205a-b6e5-4e46-8e20-520d7c327f7a@linux.dev/T/#t

Tested in bpf-next master.
No regressions.

Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/bae1205a-b6e5-4e46-8e20-520d7c327f7a@linux.dev
Link: https://lore.kernel.org/bpf/20240130110343.11217-1-jose.marchesi@oracle.com
bpf: Use -Wno-error in certain tests when building with GCC 2024-01-29T21:38:48+00:00 Jose E. Marchesi jose.marchesi@oracle.com 2024-01-27T10:07:02+00:00 646751d523587cfd7ebcf1733298ecd470879eda Certain BPF selftests contain code that, albeit being legal C, trigger warnings in GCC that cannot be disabled. This is the case for example for the tests progs/btf_dump_test_case_bitfields.c progs/btf_dump_test_case_namespacing.c progs/btf_dump_test_case_packing.c progs/btf_dump_test_case_padding.c progs/btf_dump_test_case_syntax.c which contain struct type declarations inside function parameter lists. This is problematic, because: - The BPF selftests are built with -Werror. - The Clang and GCC compilers sometimes differ when it comes to handle warnings. in the handling of warnings. One compiler may emit warnings for code that the other compiles compiles silently, and one compiler may offer the possibility to disable certain warnings, while the other doesn't. In order to overcome this problem, this patch modifies the tools/testing/selftests/bpf/Makefile in order to: 1. Enable the possibility of specifing per-source-file extra CFLAGS. This is done by defining a make variable like: <source-filename>-CFLAGS := <whateverflags> And then modifying the proper Make rule in order to use these flags when compiling <source-filename>. 2. Use the mechanism above to add -Wno-error to CFLAGS for the following selftests: progs/btf_dump_test_case_bitfields.c progs/btf_dump_test_case_namespacing.c progs/btf_dump_test_case_packing.c progs/btf_dump_test_case_padding.c progs/btf_dump_test_case_syntax.c Note the corresponding -CFLAGS variables for these files are defined only if the selftests are being built with GCC. Note that, while compiler pragmas can generally be used to disable particular warnings per file, this 1) is only possible for warning that actually can be disabled in the command line, i.e. that have -Wno-FOO options, and 2) doesn't apply to -Wno-error. Tested in bpf-next master branch. No regressions. Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240127100702.21549-1-jose.marchesi@oracle.com 
Certain BPF selftests contain code that, albeit being legal C, trigger
warnings in GCC that cannot be disabled.  This is the case for example
for the tests

  progs/btf_dump_test_case_bitfields.c
  progs/btf_dump_test_case_namespacing.c
  progs/btf_dump_test_case_packing.c
  progs/btf_dump_test_case_padding.c
  progs/btf_dump_test_case_syntax.c

which contain struct type declarations inside function parameter
lists.  This is problematic, because:

- The BPF selftests are built with -Werror.

- The Clang and GCC compilers sometimes differ when it comes to handle
  warnings.  in the handling of warnings.  One compiler may emit
  warnings for code that the other compiles compiles silently, and one
  compiler may offer the possibility to disable certain warnings, while
  the other doesn't.

In order to overcome this problem, this patch modifies the
tools/testing/selftests/bpf/Makefile in order to:

1. Enable the possibility of specifing per-source-file extra CFLAGS.
   This is done by defining a make variable like:

   <source-filename>-CFLAGS := <whateverflags>

   And then modifying the proper Make rule in order to use these flags
   when compiling <source-filename>.

2. Use the mechanism above to add -Wno-error to CFLAGS for the
   following selftests:

   progs/btf_dump_test_case_bitfields.c
   progs/btf_dump_test_case_namespacing.c
   progs/btf_dump_test_case_packing.c
   progs/btf_dump_test_case_padding.c
   progs/btf_dump_test_case_syntax.c

   Note the corresponding -CFLAGS variables for these files are
   defined only if the selftests are being built with GCC.

Note that, while compiler pragmas can generally be used to disable
particular warnings per file, this 1) is only possible for warning
that actually can be disabled in the command line, i.e. that have
-Wno-FOO options, and 2) doesn't apply to -Wno-error.

Tested in bpf-next master branch.
No regressions.

Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240127100702.21549-1-jose.marchesi@oracle.com
selftests/bpf: Attempt to build BPF programs with -Wsign-compare 2024-01-03T18:41:22+00:00 Alexei Starovoitov ast@kernel.org 2023-12-26T19:11:43+00:00 495d2d8133fd1407519170a5238f455abbd9ec9b GCC's -Wall includes -Wsign-compare while clang does not. Since BPF programs are built with clang we need to add this flag explicitly to catch problematic comparisons like: int i = -1; unsigned int j = 1; if (i < j) // this is false. long i = -1; unsigned int j = 1; if (i < j) // this is true. C standard for reference: - If either operand is unsigned long the other shall be converted to unsigned long. - Otherwise, if one operand is a long int and the other unsigned int, then if a long int can represent all the values of an unsigned int, the unsigned int shall be converted to a long int; otherwise both operands shall be converted to unsigned long int. - Otherwise, if either operand is long, the other shall be converted to long. - Otherwise, if either operand is unsigned, the other shall be converted to unsigned. Unfortunately clang's -Wsign-compare is very noisy. It complains about (s32)a == (u32)b which is safe and doen't have surprising behavior. This patch fixes some of the issues. It needs a follow up to fix the rest. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/bpf/20231226191148.48536-2-alexei.starovoitov@gmail.com 
GCC's -Wall includes -Wsign-compare while clang does not.
Since BPF programs are built with clang we need to add this flag explicitly
to catch problematic comparisons like:

  int i = -1;
  unsigned int j = 1;
  if (i < j) // this is false.

  long i = -1;
  unsigned int j = 1;
  if (i < j) // this is true.

C standard for reference:

- If either operand is unsigned long the other shall be converted to unsigned long.

- Otherwise, if one operand is a long int and the other unsigned int, then if a
long int can represent all the values of an unsigned int, the unsigned int
shall be converted to a long int; otherwise both operands shall be converted to
unsigned long int.

- Otherwise, if either operand is long, the other shall be converted to long.

- Otherwise, if either operand is unsigned, the other shall be converted to unsigned.

Unfortunately clang's -Wsign-compare is very noisy.
It complains about (s32)a == (u32)b which is safe and doen't have surprising behavior.

This patch fixes some of the issues. It needs a follow up to fix the rest.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20231226191148.48536-2-alexei.starovoitov@gmail.com
selftests/bpf: Use pkg-config for libelf 2023-11-29T06:15:29+00:00 Akihiko Odaki akihiko.odaki@daynix.com 2023-11-25T08:42:52+00:00 8998a479fd96b0b209dcb2feb468eba7eddb4ddb When linking statically, libraries may require other dependencies to be included to ld flags. In particular, libelf may require libzstd. Use pkg-config to determine such dependencies. Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20231125084253.85025-4-akihiko.odaki@daynix.com 
When linking statically, libraries may require other dependencies to be
included to ld flags. In particular, libelf may require libzstd. Use
pkg-config to determine such dependencies.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231125084253.85025-4-akihiko.odaki@daynix.com
selftests/bpf: Choose pkg-config for the target 2023-11-29T06:15:29+00:00 Akihiko Odaki akihiko.odaki@daynix.com 2023-11-25T08:42:50+00:00 2ce344b6891618063c0bebe22d9cdf9c086e0aa8 pkg-config is used to build sign-file executable. It should use the library for the target instead of the host as it is called during tests. Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20231125084253.85025-2-akihiko.odaki@daynix.com 
pkg-config is used to build sign-file executable. It should use the
library for the target instead of the host as it is called during tests.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231125084253.85025-2-akihiko.odaki@daynix.com