From d18acd15c6dfb669f0463afa31ac5343594d2fe2 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Tue, 15 Nov 2016 04:05:44 +0000 Subject: [PATCH] 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 Cc: Alexei Starovoitov Cc: He Kuang Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/20161115040617.69788-2-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/util.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 53 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c index 5bbd1f609f1f..67ac765da27a 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -637,12 +637,63 @@ bool find_process(const char *name) return ret ? false : true; } +static int +fetch_ubuntu_kernel_version(unsigned int *puint) +{ + ssize_t len; + size_t line_len = 0; + char *ptr, *line = NULL; + int version, patchlevel, sublevel, err; + FILE *vsig = fopen("/proc/version_signature", "r"); + + if (!vsig) { + pr_debug("Open /proc/version_signature failed: %s\n", + strerror(errno)); + return -1; + } + + len = getline(&line, &line_len, vsig); + fclose(vsig); + err = -1; + if (len <= 0) { + pr_debug("Reading from /proc/version_signature failed: %s\n", + strerror(errno)); + goto errout; + } + + ptr = strrchr(line, ' '); + if (!ptr) { + pr_debug("Parsing /proc/version_signature failed: %s\n", line); + goto errout; + } + + err = sscanf(ptr + 1, "%d.%d.%d", + &version, &patchlevel, &sublevel); + if (err != 3) { + pr_debug("Unable to get kernel version from /proc/version_signature '%s'\n", + line); + goto errout; + } + + if (puint) + *puint = (version << 16) + (patchlevel << 8) + sublevel; + err = 0; +errout: + free(line); + return err; +} + int fetch_kernel_version(unsigned int *puint, char *str, size_t str_size) { struct utsname utsname; int version, patchlevel, sublevel, err; + bool int_ver_ready = false; + + if (access("/proc/version_signature", R_OK) == 0) + if (!fetch_ubuntu_kernel_version(puint)) + int_ver_ready = true; if (uname(&utsname)) return -1; @@ -656,12 +707,12 @@ fetch_kernel_version(unsigned int *puint, char *str, &version, &patchlevel, &sublevel); if (err != 3) { - pr_debug("Unablt to get kernel version from uname '%s'\n", + pr_debug("Unable to get kernel version from uname '%s'\n", utsname.release); return -1; } - if (puint) + if (puint && !int_ver_ready) *puint = (version << 16) + (patchlevel << 8) + sublevel; return 0; } -- 2.11.0