Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH perf/core v2 4/4] perf-probe: Find probe events without target module | Date | Wed, 11 Jan 2017 15:03:06 +0900 |
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Find probe events without -m "module" option. If perf-probe failed to find given function in kernel image, it tries to find same symbol and module in kallsyms, and retry search in the found module. E.g.
# perf probe -D i915_capabilities p:probe/i915_capabilities i915:i915_capabilities+0
Note: without -m option, perf probe can not find inlined function since there is no symbol information in kallsyms.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- Changes in v2: - Fix to remove unneeded zero-return. - Remove unneeded debug message. --- tools/perf/util/probe-event.c | 69 ++++++++++++++++++++++++++++++----------- 1 file changed, 51 insertions(+), 18 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 6a6f44d..715f330 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -858,11 +858,7 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev, debuginfo__delete(dinfo); - if (ntevs == 0) { /* No error but failed to find probe point. */ - pr_warning("Probe point '%s' not found.\n", - synthesize_perf_probe_point(&pev->point)); - return -ENOENT; - } else if (ntevs < 0) { + if (ntevs < 0) { /* Error path : ntevs < 0 */ pr_debug("An error occurred in debuginfo analysis (%d).\n", ntevs); if (ntevs == -EBADF) @@ -2829,9 +2825,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev, */ num_matched_functions = find_probe_functions(map, pp->function, syms); if (num_matched_functions == 0) { - pr_err("Failed to find symbol %s in %s\n", pp->function, - pev->target ? : "kernel"); - ret = -ENOENT; + ret = 0; goto out; } else if (num_matched_functions > probe_conf.max_probes) { pr_err("Too many functions matched in %s\n", @@ -3233,6 +3227,42 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev, return ret; } +static int __convert_to_probe_trace_events(struct perf_probe_event *pev, + struct probe_trace_event **tevs) +{ + int ret; + + /* At first, we need to lookup cache entry */ + ret = find_probe_trace_events_from_cache(pev, tevs); + if (ret > 0 || pev->sdt) /* SDT can be found only in the cache */ + return ret == 0 ? -ENOENT : ret; /* Found in probe cache */ + + /* Convert perf_probe_event with debuginfo */ + ret = try_to_find_probe_trace_events(pev, tevs); + if (ret != 0) + return ret; /* Found in debuginfo or got an error */ + + return find_probe_trace_events_from_map(pev, tevs); +} + +static char *find_module_from_kallsyms(const char *symbol_name) +{ + struct machine *machine = machine__new_kallsyms(); + struct symbol *sym; + struct map *map; + char *module; + + sym = machine__find_kernel_function_by_name(machine, symbol_name, &map); + if (!sym || map->dso->short_name[0] != '[') + return NULL; + pr_debug("Found %s in %s\n", sym->name, map->dso->short_name); + module = strdup(map->dso->short_name + 1); + if (module) + module[strlen(module) - 1] = '\0'; + + return module; +} + static int convert_to_probe_trace_events(struct perf_probe_event *pev, struct probe_trace_event **tevs) { @@ -3255,17 +3285,20 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev, if (ret > 0) return ret; - /* At first, we need to lookup cache entry */ - ret = find_probe_trace_events_from_cache(pev, tevs); - if (ret > 0 || pev->sdt) /* SDT can be found only in the cache */ - return ret == 0 ? -ENOENT : ret; /* Found in probe cache */ - - /* Convert perf_probe_event with debuginfo */ - ret = try_to_find_probe_trace_events(pev, tevs); - if (ret != 0) - return ret; /* Found in debuginfo or got an error */ + ret = __convert_to_probe_trace_events(pev, tevs); + /* Not found. will retry to check kmodule if possible */ + if (ret == 0 && !pev->uprobes && !pev->target) { + pev->target = find_module_from_kallsyms(pev->point.function); + if (pev->target) + ret = __convert_to_probe_trace_events(pev, tevs); + } - return find_probe_trace_events_from_map(pev, tevs); + if (ret == 0) { + pr_warning("Probe point '%s' not found.\n", + synthesize_perf_probe_point(&pev->point)); + ret = -ENOENT; + } + return ret; } int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs)
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