Arnaldo, could you also apply this?
This will helps users to find the reason why perf probe failed
to open the debuginfo.
On 2015/05/12 12:40, Masami Hiramatsu wrote:
> Show the reason of error when dso__load* failed. This shows
> when user gives wrong kernel image or wrong path.
>
> Without this, perf probe shows an obscure message.
> ----
> $ perf probe -k ~/kbin/linux-3.x86_64/vmlinux -L vfs_read
> Failed to find path of kernel module.
> Error: Failed to show lines.
> ----
>
> With this, perf shows appropriate error message.
> ----
> $ perf probe -k ~/kbin/linux-3.x86_64/vmlinux -L vfs_read
> Failed to find the path for kernel: Mismatching build id
> Error: Failed to show lines.
> ----
> And
> ----
> $ perf probe -k /non-exist/kernel/vmlinux -L vfs_read
> Failed to find the path for kernel: No such file or directory
> Error: Failed to show lines.
> ----
>
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
> ---
> tools/perf/util/probe-event.c | 47
> +++++++++++++++++++++--------------------
> tools/perf/util/probe-event.h | 3 ---
> 2 files changed, 24 insertions(+), 26 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index a2d8cef..a4830a6 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -201,11 +201,12 @@ static void put_target_map(struct map *map, bool user)
> }
>
>
> -static struct dso *kernel_get_module_dso(const char *module)
> +static int kernel_get_module_dso(const char *module, struct dso **pdso)
> {
> struct dso *dso;
> struct map *map;
> const char *vmlinux_name;
> + int ret = 0;
>
> if (module) {
> list_for_each_entry(dso, &host_machine->kernel_dsos.head,
> @@ -215,30 +216,21 @@ static struct dso *kernel_get_module_dso(const char
> *module)
> goto found;
> }
> pr_debug("Failed to find module %s.\n", module);
> - return NULL;
> + return -ENOENT;
> }
>
> map = host_machine->vmlinux_maps[MAP__FUNCTION];
> dso = map->dso;
>
> vmlinux_name = symbol_conf.vmlinux_name;
> - if (vmlinux_name) {
> - if (dso__load_vmlinux(dso, map, vmlinux_name, false, NULL) <= 0)
> - return NULL;
> - } else {
> - if (dso__load_vmlinux_path(dso, map, NULL) <= 0) {
> - pr_debug("Failed to load kernel map.\n");
> - return NULL;
> - }
> - }
> + dso->load_errno = 0;
> + if (vmlinux_name)
> + ret = dso__load_vmlinux(dso, map, vmlinux_name, false, NULL);
> + else
> + ret = dso__load_vmlinux_path(dso, map, NULL);
> found:
> - return dso;
> -}
> -
> -const char *kernel_get_module_path(const char *module)
> -{
> - struct dso *dso = kernel_get_module_dso(module);
> - return (dso) ? dso->long_name : NULL;
> + *pdso = dso;
> + return ret;
> }
>
> static int convert_exec_to_group(const char *exec, char **result)
> @@ -390,16 +382,25 @@ static int get_alternative_line_range(struct debuginfo
> *dinfo,
> static struct debuginfo *open_debuginfo(const char *module, bool silent)
> {
> const char *path = module;
> - struct debuginfo *ret;
> + char reason[STRERR_BUFSIZE];
> + struct debuginfo *ret = NULL;
> + struct dso *dso = NULL;
> + int err;
>
> if (!module || !strchr(module, '/')) {
> - path = kernel_get_module_path(module);
> - if (!path) {
> + err = kernel_get_module_dso(module, &dso);
> + if (err < 0) {
> + if (!dso || dso->load_errno == 0) {
> + if (!strerror_r(-err, reason, STRERR_BUFSIZE))
> + strcpy(reason, "(unknown)");
> + } else
> + dso__strerror_load(dso, reason, STRERR_BUFSIZE);
> if (!silent)
> - pr_err("Failed to find path of %s module.\n",
> - module ?: "kernel");
> + pr_err("Failed to find the path for %s: %s\n",
> + module ?: "kernel", reason);
> return NULL;
> }
> + path = dso->long_name;
> }
> ret = debuginfo__new(path);
> if (!ret && !silent) {
> diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
> index 537eb32..31db6ee 100644
> --- a/tools/perf/util/probe-event.h
> +++ b/tools/perf/util/probe-event.h
> @@ -131,9 +131,6 @@ extern void line_range__clear(struct line_range *lr);
> /* Initialize line range */
> extern int line_range__init(struct line_range *lr);
>
> -/* Internal use: Return kernel/module path */
> -extern const char *kernel_get_module_path(const char *module);
> -
> extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs);
> extern int del_perf_probe_events(struct strfilter *filter);
> extern int show_perf_probe_events(struct strfilter *filter);
>
>
--
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: masami.hiramatsu...@hitachi.com
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