[GIT PULL] perf fixes

From: Ingo Molnar
Date: Fri Jan 08 2016 - 07:47:03 EST


Linus,

Please pull the latest perf-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf-urgent-for-linus

# HEAD: 12ca6ad2e3a896256f086497a7c7406a547ee373 perf: Fix race in swevent hash

Two core subsystem fixes, plus a handful of tooling fixes.

Thanks,

Ingo

------------------>
Arnaldo Carvalho de Melo (2):
perf list: Add support for PERF_COUNT_SW_BPF_OUT
perf list: Robustify event printing routine

Michael Petlan (2):
perf buildid-list: Show running kernel build id fix
perf buildid-list: Fix return value of perf buildid-list -k

Peter Zijlstra (2):
perf: Fix race in perf_event_exec()
perf: Fix race in swevent hash

Wang Nan (3):
perf hists browser: Add NULL pointer check to prevent crash
perf hists browser: Reset selection when refresh
perf hists browser: Fix segfault if use symbol filter in cmdline


kernel/events/core.c | 35 ++++++-----------------------------
tools/perf/builtin-buildid-list.c | 2 +-
tools/perf/ui/browsers/hists.c | 8 ++++++++
tools/perf/util/build-id.c | 2 +-
tools/perf/util/parse-events.c | 6 +++++-
5 files changed, 21 insertions(+), 32 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 39cf4a40aa4c..0a791a2203dc 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3154,15 +3154,16 @@ static int event_enable_on_exec(struct perf_event *event,
* Enable all of a task's events that have been marked enable-on-exec.
* This expects task == current.
*/
-static void perf_event_enable_on_exec(struct perf_event_context *ctx)
+static void perf_event_enable_on_exec(int ctxn)
{
- struct perf_event_context *clone_ctx = NULL;
+ struct perf_event_context *ctx, *clone_ctx = NULL;
struct perf_event *event;
unsigned long flags;
int enabled = 0;
int ret;

local_irq_save(flags);
+ ctx = current->perf_event_ctxp[ctxn];
if (!ctx || !ctx->nr_events)
goto out;

@@ -3205,17 +3206,11 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)

void perf_event_exec(void)
{
- struct perf_event_context *ctx;
int ctxn;

rcu_read_lock();
- for_each_task_context_nr(ctxn) {
- ctx = current->perf_event_ctxp[ctxn];
- if (!ctx)
- continue;
-
- perf_event_enable_on_exec(ctx);
- }
+ for_each_task_context_nr(ctxn)
+ perf_event_enable_on_exec(ctxn);
rcu_read_unlock();
}

@@ -6493,9 +6488,6 @@ struct swevent_htable {

/* Recursion avoidance in each contexts */
int recursion[PERF_NR_CONTEXTS];
-
- /* Keeps track of cpu being initialized/exited */
- bool online;
};

static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
@@ -6753,14 +6745,8 @@ static int perf_swevent_add(struct perf_event *event, int flags)
hwc->state = !(flags & PERF_EF_START);

head = find_swevent_head(swhash, event);
- if (!head) {
- /*
- * We can race with cpu hotplug code. Do not
- * WARN if the cpu just got unplugged.
- */
- WARN_ON_ONCE(swhash->online);
+ if (WARN_ON_ONCE(!head))
return -EINVAL;
- }

hlist_add_head_rcu(&event->hlist_entry, head);
perf_event_update_userpage(event);
@@ -6828,7 +6814,6 @@ static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
int err = 0;

mutex_lock(&swhash->hlist_mutex);
-
if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
struct swevent_hlist *hlist;

@@ -9291,7 +9276,6 @@ static void perf_event_init_cpu(int cpu)
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);

mutex_lock(&swhash->hlist_mutex);
- swhash->online = true;
if (swhash->hlist_refcount > 0) {
struct swevent_hlist *hlist;

@@ -9333,14 +9317,7 @@ static void perf_event_exit_cpu_context(int cpu)

static void perf_event_exit_cpu(int cpu)
{
- struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
-
perf_event_exit_cpu_context(cpu);
-
- mutex_lock(&swhash->hlist_mutex);
- swhash->online = false;
- swevent_hlist_release(swhash);
- mutex_unlock(&swhash->hlist_mutex);
}
#else
static inline void perf_event_exit_cpu(int cpu) { }
diff --git a/tools/perf/builtin-buildid-list.c b/tools/perf/builtin-buildid-list.c
index 918b4de29de4..6419f57b0850 100644
--- a/tools/perf/builtin-buildid-list.c
+++ b/tools/perf/builtin-buildid-list.c
@@ -110,7 +110,7 @@ int cmd_buildid_list(int argc, const char **argv,
setup_pager();

if (show_kernel)
- return sysfs__fprintf_build_id(stdout);
+ return !(sysfs__fprintf_build_id(stdout) > 0);

return perf_session__list_build_ids(force, with_hits);
}
diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index fa9eb92c9e24..81def6c3f24b 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -298,6 +298,9 @@ static bool hist_browser__toggle_fold(struct hist_browser *browser)
struct callchain_list *cl = container_of(ms, struct callchain_list, ms);
bool has_children;

+ if (!he || !ms)
+ return false;
+
if (ms == &he->ms)
has_children = hist_entry__toggle_fold(he);
else
@@ -928,6 +931,8 @@ static unsigned int hist_browser__refresh(struct ui_browser *browser)
}

ui_browser__hists_init_top(browser);
+ hb->he_selection = NULL;
+ hb->selection = NULL;

for (nd = browser->top; nd; nd = rb_next(nd)) {
struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
@@ -1033,6 +1038,9 @@ static void ui_browser__hists_seek(struct ui_browser *browser,
* and stop when we printed enough lines to fill the screen.
*/
do_offset:
+ if (!nd)
+ return;
+
if (offset > 0) {
do {
h = rb_entry(nd, struct hist_entry, rb_node);
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 217b5a60e2ab..6a7e273a514a 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -91,7 +91,7 @@ int build_id__sprintf(const u8 *build_id, int len, char *bf)
bid += 2;
}

- return raw - build_id;
+ return (bid - bf) + 1;
}

int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index e48d9da75707..6fc8cd753e1a 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -124,6 +124,10 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
.symbol = "dummy",
.alias = "",
},
+ [PERF_COUNT_SW_BPF_OUTPUT] = {
+ .symbol = "bpf-output",
+ .alias = "",
+ },
};

#define __PERF_EVENT_FIELD(config, name) \
@@ -1879,7 +1883,7 @@ void print_symbol_events(const char *event_glob, unsigned type,

for (i = 0; i < max; i++, syms++) {

- if (event_glob != NULL &&
+ if (event_glob != NULL && syms->symbol != NULL &&
!(strglobmatch(syms->symbol, event_glob) ||
(syms->alias && strglobmatch(syms->alias, event_glob))))
continue;