-
When a test is in the FEATURE_TESTS_BASIC list in tools/build/Makefile.feature
must be added to tools/build/feature/test-all.c, because the successfull
compilation and linking of that test-all.bin file means that all the
features listed in FEATURE_TESTS_BASIC are present in the system, so we
don't have to go on feature by feature test building them.Since reallocarray() is expected to be present in modern systems, it has
a place in FEATURE_TESTS_BASIC, so that we speed up the build process
building just that file.For older systems, such as ubuntu:16.04 (build failure reported by Jin
Yao) debian:8, and for the current flagship RHEL distro, RHEL7, the
build will fail as test-all.bin (without test-reallocarray.c included)
passes but reallocarray() isn't present, making the build fail with:CC /tmp/build/perf/libbpf.o
MKDIR /tmp/build/perf/fs/
CC /tmp/build/perf/fs/tracing_path.o
LD /tmp/build/perf/fd/libapi-in.o
CC /tmp/build/perf/bpf.o
libbpf.c: In function 'bpf_object__add_program':
libbpf.c:367:10: error: implicit declaration of function 'reallocarray' [-Werror=implicit-function-declaration]
progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
^
libbpf.c:367:2: error: nested extern declaration of 'reallocarray' [-Werror=nested-externs]
progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
^
libbpf.c:367:8: error: assignment makes pointer from integer without a cast [-Werror=int-conversion]
progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
^
libbpf.c: In function 'bpf_object__elf_collect':
libbpf.c:887:10: error: assignment makes pointer from integer without a cast [-Werror=int-conversion]
reloc = reallocarray(reloc, nr_reloc,
^
libbpf.c: In function 'bpf_program__reloc_text':
libbpf.c:1394:12: error: assignment makes pointer from integer without a cast [-Werror=int-conversion]
new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
^
CC /tmp/build/perf/nlattr.oEven with:
$ grep reallocarray /tmp/build/perf/FEATURE-DUMP
feature-reallocarray=1
$Which ubuntu:16.04.5 LTS doesn't have:
perfbuilder@38a153a1bba8:/$ head -2 /etc/os-release
NAME="Ubuntu"
VERSION="16.04.5 LTS (Xenial Xerus)"
perfbuilder@38a153a1bba8:/$ find /usr/include/ -name "*.h" | xargs grep -w reallocarray
perfbuilder@38a153a1bba8:/$Fix it by including it to test-all.c, which ends up forcing the
individual tests to be triggered and for the build process to notice
that indeed reallocarray() is not there:perfbuilder@38a153a1bba8:/$ cat /tmp/build/perf/feature/test-all.make.output
In file included from test-all.c:178:0:
test-reallocarray.c: In function 'main_test_reallocarray':
test-reallocarray.c:7:11: error: implicit declaration of function 'reallocarray' [-Werror=implicit-function-declaration]
return !!reallocarray(NULL, 1, 1);
^
cc1: all warnings being treated as errors
perfbuilder@38a153a1bba8:/$That is the only test that is failing on Ubuntu 16.03.5 LTS, so all
tests are forced:perfbuilder@38a153a1bba8:/tmp/build/perf/feature$ ls -lSr *.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 15:00 test-dwarf.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 14:16 test-cplus-demangle.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 15:00 test-bpf.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 15:00 test-backtrace.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 104 Feb 14 15:00 test-bionic.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 107 Feb 14 15:00 test-libunwind-x86.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 115 Feb 14 15:00 test-libunwind-aarch64.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 122 Feb 14 15:00 test-libbabeltrace.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 254 Feb 14 15:00 test-reallocarray.make.output
-rw-r--r--. 1 perfbuilder perfbuilder 312 Feb 14 15:00 test-all.make.output
perfbuilder@38a153a1bba8:/tmp/build/perf/feature$And that reallocarray() one shows:
perfbuilder@38a153a1bba8:/tmp/build/perf/feature$ cat test-reallocarray.make.output
test-reallocarray.c: In function 'main':
test-reallocarray.c:7:11: error: implicit declaration of function 'reallocarray' [-Werror=implicit-function-declaration]
return !!reallocarray(NULL, 1, 1);
^
cc1: all warnings being treated as errors
perfbuilder@38a153a1bba8:/tmp/build/perf/feature$Which now generates the expected result:
perfbuilder@38a153a1bba8:~$ grep reallocarray /tmp/build/perf/FEATURE-DUMP
feature-reallocarray=0
perfbuilder@38a153a1bba8:~$The fallback mechanism kicks in and libbpf and perf are again buildable
in systems without reallocarray():$ cat tools/include/tools/libc_compat.h
// SPDX-License-Identifier: (LGPL-2.0+ OR BSD-2-Clause)
/* Copyright (C) 2018 Netronome Systems, Inc. */#ifndef __TOOLS_LIBC_COMPAT_H
#define __TOOLS_LIBC_COMPAT_H#include
#include#ifdef COMPAT_NEED_REALLOCARRAY
static inline void *reallocarray(void *ptr, size_t nmemb, size_t size)
{
size_t bytes;if (unlikely(check_mul_overflow(nmemb, size, &bytes)))
return NULL;
return realloc(ptr, bytes);
}
#endif
#endif
$Reported-by: Jin Yao
Acked-by: Jiri Olsa
Cc: Adrian Hunter
Cc: Alexei Starovoitov
Cc: Andrii Nakryiko
Cc: Daniel Borkmann
Cc: Jakub Kicinski
Cc: Namhyung Kim
Cc: Song Liu
Cc: Yonghong Song
Fixes: 531b014e7a2f ("tools: bpf: make use of reallocarray")
Link: https://lkml.kernel.org/n/tip-aonqku8axii8rxki5g11w40b@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo