Commits
Wang Nan committed d18acd15c6d
perf tools: Fix kernel version error in ubuntu
On ubuntu the internal kernel version code is different from what can
be retrived from uname:
$ uname -r
4.4.0-47-generic
$ cat /lib/modules/`uname -r`/build/include/generated/uapi/linux/version.h
#define LINUX_VERSION_CODE 263192
#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
$ cat /lib/modules/`uname -r`/build/include/generated/utsrelease.h
#define UTS_RELEASE "4.4.0-47-generic"
#define UTS_UBUNTU_RELEASE_ABI 47
$ cat /proc/version_signature
Ubuntu 4.4.0-47.68-generic 4.4.24
The macro LINUX_VERSION_CODE is set to 4.4.24 (263192 == 0x40418), but
`uname -r` reports 4.4.0.
This mismatch causes LINUX_VERSION_CODE macro passed to BPF script become
an incorrect value, results in magic failure in BPF loading:
$ sudo ./buildperf/perf record -e ./tools/perf/tests/bpf-script-example.c ls
event syntax error: './tools/perf/tests/bpf-script-example.c'
\___ Failed to load program for unknown reason
According to Ubuntu document (https://wiki.ubuntu.com/Kernel/FAQ), the
correct kernel version can be retrived through /proc/version_signature, which
is ubuntu specific.
This patch checks the existance of /proc/version_signature, and returns
version number through parsing this file instead of uname. Version string
is untouched (value returns from uname) because `uname -r` is required
to be consistence with path of kbuild directory in /lib/module.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/20161115040617.69788-2-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>