From: Wang Nan <wangn...@huawei.com>
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 <wangn...@huawei.com>
Cc: Alexei Starovoitov <a...@fb.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
Link: http://lkml.kernel.org/r/20161115040617.69788-2-wangn...@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
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;
}
--
2.7.4
