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Date: Wed, 27 Apr 2016 21:04:53 +0530
From: Hemant Kumar <hemant@...ux.vnet.ibm.com>
To: Masami Hiramatsu <mhiramat@...nel.org>
CC: Arnaldo Carvalho de Melo <acme@...nel.org>,
linux-kernel@...r.kernel.org, Namhyung Kim <namhyung@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>
Subject: Re: [PATCH perf/core v4 18/19] perf probe: Allow wildcard for cached
events
On 04/26/2016 02:34 PM, Masami Hiramatsu wrote:
> Allo glob wildcard for reusing cached/SDT events. This also
> automatically find the target binaries, e.g.
>
> # perf probe -a %sdt_libc:\*
>
> This example adds probes for all SDT in libc.
> Note that the SDTs must have been scanned by perf buildid-cache.
There is a segfault after applying this patch :
# perf probe -x /home/hemant/test %marker1
Segmentation fault (core dumped)
The problem is there is no group name with this marker and
strglobmatch tries to match entry->pev.group with pev->group (which is
NULL).
> Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
> ---
> tools/perf/util/probe-event.c | 153 ++++++++++++++++++++++++++++++++++++++++-
> tools/perf/util/probe-event.h | 1
> tools/perf/util/probe-file.c | 33 ++++++++-
> tools/perf/util/probe-file.h | 5 +
> 4 files changed, 183 insertions(+), 9 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 1128631..3bd81f0 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -236,7 +236,7 @@ static void clear_perf_probe_point(struct perf_probe_point *pp)
> free(pp->lazy_line);
> }
>
> -static void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs)
> +void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs)
> {
> int i;
>
> @@ -1151,7 +1151,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
> ptr = strchr(*arg, ':');
> if (ptr) {
> *ptr = '\0';
> - if (!is_c_func_name(*arg))
> + if (!pev->sdt && !is_c_func_name(*arg))
> goto ng_name;
> pev->group = strdup(*arg);
> if (!pev->group)
> @@ -1159,7 +1159,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
> *arg = ptr + 1;
> } else
> pev->group = NULL;
> - if (!is_c_func_name(*arg)) {
> + if (!pev->sdt && !is_c_func_name(*arg)) {
> ng_name:
> semantic_error("%s is bad for event name -it must "
> "follow C symbol-naming rule.\n", *arg);
> @@ -1585,6 +1585,11 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev)
> p = strchr(argv[1], ':');
> if (p) {
> tp->module = strndup(argv[1], p - argv[1]);
> + if (!tp->module) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + tev->uprobes = (tp->module[0] == '/');
> p++;
> } else
> p = argv[1];
> @@ -2430,7 +2435,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
> int ret;
>
> /* If probe_event or trace_event already have the name, reuse it */
> - if (pev->event)
> + if (pev->event && !pev->sdt)
> event = pev->event;
> else if (tev->event)
> event = tev->event;
> @@ -2443,7 +2448,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
> else
> event = tev->point.realname;
> }
> - if (pev->group)
> + if (pev->group && !pev->sdt)
> group = pev->group;
> else if (tev->group)
> group = tev->group;
> @@ -2794,6 +2799,137 @@ errout:
>
> bool __weak arch__prefers_symtab(void) { return false; }
>
> +/* Concatinate two arrays */
> +static void *memcat(void *a, size_t sz_a, void *b, size_t sz_b)
> +{
> + void *ret;
> +
> + ret = malloc(sz_a + sz_b);
> + if (ret) {
> + memcpy(ret, a, sz_a);
> + memcpy(ret + sz_a, b, sz_b);
> + }
> + return ret;
> +}
> +
> +static int
> +concat_probe_trace_events(struct probe_trace_event **tevs, int *ntevs,
> + struct probe_trace_event **tevs2, int ntevs2)
> +{
> + struct probe_trace_event *new_tevs;
> + int ret = 0;
> +
> + if (ntevs == 0) {
> + *tevs = *tevs2;
> + *ntevs = ntevs2;
> + *tevs2 = NULL;
> + return 0;
> + }
> +
> + if (*ntevs + ntevs2 > probe_conf.max_probes)
> + ret = -E2BIG;
> + else {
> + /* Concatinate the array of probe_trace_event */
> + new_tevs = memcat(*tevs, (*ntevs) * sizeof(**tevs),
> + *tevs2, ntevs2 * sizeof(**tevs2));
> + if (!new_tevs)
> + ret = -ENOMEM;
> + else {
> + free(*tevs);
> + *tevs = new_tevs;
> + *ntevs += ntevs2;
> + }
> + }
> + if (ret < 0)
> + clear_probe_trace_events(*tevs2, ntevs2);
> + zfree(tevs2);
> +
> + return ret;
> +}
> +
> +/* Try to find probe_trace_event from given probe caches */
> +static int find_cached_events(struct perf_probe_event *pev,
> + struct probe_trace_event **tevs,
> + const char *target)
> +{
> + struct probe_cache *cache;
> + struct probe_cache_entry *entry;
> + struct probe_trace_event *tmp_tevs = NULL;
> + int ntevs = 0;
> + int ret = 0;
> +
> + cache = probe_cache__new(target);
> + if (!cache)
> + return -ENOENT;
> +
> + for_each_probe_cache_entry(entry, cache) {
> + /* Skip the cache entry which has no name */
> + if (!entry->pev.event || !entry->pev.group)
> + continue;
> + if (strglobmatch(entry->pev.group, pev->group) &&
> + strglobmatch(entry->pev.event, pev->event)) {
Due to the above issue, we can change the above condition to :
if (strglobmatch(entry->pev.event, pev->event) {
if (!pev->group || (pev->group && strglobmatch(entry->pev.group,
pev->group)))
// Do stuff
}
> + ret = probe_cache_entry__get_event(entry, &tmp_tevs);
> + if (ret > 0)
> + ret = concat_probe_trace_events(tevs, &ntevs,
> + &tmp_tevs, ret);
> + if (ret < 0)
> + break;
> + }
> + }
> + probe_cache__delete(cache);
> + if (ret < 0) {
> + clear_probe_trace_events(*tevs, ntevs);
> + zfree(tevs);
> + } else {
> + ret = ntevs;
> + if (target[0] == '/')
> + pev->uprobes = true;
> + }
> +
> + return ret;
> +}
> +
> +/* Try to find probe_trace_event from all probe caches */
> +static int find_cached_events_all(struct perf_probe_event *pev,
> + struct probe_trace_event **tevs)
> +{
> + struct probe_trace_event *tmp_tevs = NULL;
> + struct strlist *bidlist;
> + struct str_node *nd;
> + char *pathname;
> + int ntevs = 0;
> + int ret;
> +
> + /* Get the buildid list of all valid caches */
> + ret = build_id_cache__list_all(&bidlist, true);
> + if (ret < 0) {
> + pr_debug("Failed to get buildids: %d\n", ret);
> + return ret;
> + }
> +
> + ret = 0;
> + strlist__for_each(nd, bidlist) {
> + pathname = build_id_cache__origname(nd->s);
> + ret = find_cached_events(pev, &tmp_tevs, pathname);
> + if (ret > 0)
> + ret = concat_probe_trace_events(tevs, &ntevs,
> + &tmp_tevs, ret);
> + /* In the case of cnt == 0, we just skip it */
> + free(pathname);
> + if (ret < 0)
> + break;
> + }
> + strlist__delete(bidlist);
> +
> + if (ret < 0) {
> + clear_probe_trace_events(*tevs, ntevs);
> + zfree(tevs);
> + } else
> + ret = ntevs;
> +
> + return ret;
> +}
> +
> static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
> struct probe_trace_event **tevs)
> {
> @@ -2803,6 +2939,13 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
> struct str_node *node;
> int ret, i;
>
> + if (pev->sdt) {
> + /* For SDT/cached events, we use special search functions */
> + if (!pev->target)
> + return find_cached_events_all(pev, tevs);
> + else
> + return find_cached_events(pev, tevs, pev->target);
> + }
> cache = probe_cache__new(pev->target);
> if (!cache)
> return 0;
> diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
> index 2a23efe..39b5a35 100644
> --- a/tools/perf/util/probe-event.h
> +++ b/tools/perf/util/probe-event.h
> @@ -134,6 +134,7 @@ bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
> /* Release event contents */
> void clear_perf_probe_event(struct perf_probe_event *pev);
> void clear_probe_trace_event(struct probe_trace_event *tev);
> +void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs);
>
> /* Command string to line-range */
> int parse_line_range_desc(const char *cmd, struct line_range *lr);
> diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
> index 2437b48..896d645 100644
> --- a/tools/perf/util/probe-file.c
> +++ b/tools/perf/util/probe-file.c
> @@ -360,6 +360,31 @@ probe_cache_entry__new(struct perf_probe_event *pev)
> return ret;
> }
>
> +int probe_cache_entry__get_event(struct probe_cache_entry *entry,
> + struct probe_trace_event **tevs)
> +{
> + struct probe_trace_event *tev;
> + struct str_node *node;
> + int ret, i;
> +
> + ret = strlist__nr_entries(entry->tevlist);
> + if (ret > probe_conf.max_probes)
> + return -E2BIG;
> +
> + *tevs = zalloc(ret * sizeof(*tev));
> + if (!*tevs)
> + return -ENOMEM;
> +
> + i = 0;
> + strlist__for_each(node, entry->tevlist) {
> + tev = &(*tevs)[i++];
> + ret = parse_probe_trace_command(node->s, tev);
> + if (ret < 0)
> + break;
> + }
> + return i;
> +}
> +
> /* For the kernel probe caches, pass target = NULL */
> static int probe_cache__open(struct probe_cache *pcache, const char *target)
> {
> @@ -528,7 +553,7 @@ probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
> if (!cmd)
> return NULL;
>
> - list_for_each_entry(entry, &pcache->list, list) {
> + for_each_probe_cache_entry(entry, pcache) {
> if (pev->sdt) {
> if (entry->pev.event &&
> streql(entry->pev.event, pev->event) &&
> @@ -558,7 +583,7 @@ probe_cache__find_by_name(struct probe_cache *pcache,
> {
> struct probe_cache_entry *entry = NULL;
>
> - list_for_each_entry(entry, &pcache->list, list) {
> + for_each_probe_cache_entry(entry, pcache) {
> /* Hit if same event name or same command-string */
> if (streql(entry->pev.group, group) &&
> streql(entry->pev.event, event))
> @@ -711,7 +736,7 @@ int probe_cache__commit(struct probe_cache *pcache)
> if (ret < 0)
> goto out;
>
> - list_for_each_entry(entry, &pcache->list, list) {
> + for_each_probe_cache_entry(entry, pcache) {
> ret = probe_cache_entry__write(entry, pcache->fd);
> pr_debug("Cache committed: %d\n", ret);
> if (ret < 0)
> @@ -750,7 +775,7 @@ static int probe_cache__show_entries(struct probe_cache *pcache,
> {
> struct probe_cache_entry *entry;
>
> - list_for_each_entry(entry, &pcache->list, list) {
> + for_each_probe_cache_entry(entry, pcache) {
> if (probe_cache_entry__compare(entry, filter))
> printf("%s\n", entry->spev);
> }
> diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h
> index 55322f1..a02bbbd 100644
> --- a/tools/perf/util/probe-file.h
> +++ b/tools/perf/util/probe-file.h
> @@ -32,6 +32,11 @@ struct probe_cache {
> struct list_head list;
> };
>
> +int probe_cache_entry__get_event(struct probe_cache_entry *entry,
> + struct probe_trace_event **tevs);
> +#define for_each_probe_cache_entry(entry, pcache) \
> + list_for_each_entry(entry, &pcache->list, list)
> +
> struct probe_cache *probe_cache__new(const char *target);
> int probe_cache__add_entry(struct probe_cache *pcache,
> struct perf_probe_event *pev,
>
--
Thanks,
Hemant Kumar
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