linux-kernel - [GIT PULL] perf fixes

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Message-ID: <20191221161624.GA130017@gmail.com>
Date:   Sat, 21 Dec 2019 17:16:24 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Thomas Gleixner <tglx@...utronix.de>,
        Arnaldo Carvalho de Melo <acme@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] perf fixes


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: 9f0bff1180efc9ea988fed3fd93da7647151ac8b perf/core: Add SRCU annotation for pmus list walk

Misc fixes: a BTS fix, a PT NMI handling fix, a PMU sysfs fix and an SRCU 
annotation.

 Thanks,

	Ingo

------------------>
Alexander Shishkin (2):
      perf/x86/intel/bts: Fix the use of page_private()
      perf/x86/intel: Fix PT PMI handling

Peter Zijlstra (1):
      perf/x86: Fix potential out-of-bounds access

Sebastian Andrzej Siewior (1):
      perf/core: Add SRCU annotation for pmus list walk


 arch/x86/events/core.c      | 19 +++++++++++++++----
 arch/x86/events/intel/bts.c | 16 +++++++++++-----
 kernel/events/core.c        |  2 +-
 3 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 9a89d98c55bd..f118af9f0718 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -376,7 +376,7 @@ int x86_add_exclusive(unsigned int what)
 	 * LBR and BTS are still mutually exclusive.
 	 */
 	if (x86_pmu.lbr_pt_coexist && what == x86_lbr_exclusive_pt)
-		return 0;
+		goto out;
 
 	if (!atomic_inc_not_zero(&x86_pmu.lbr_exclusive[what])) {
 		mutex_lock(&pmc_reserve_mutex);
@@ -388,6 +388,7 @@ int x86_add_exclusive(unsigned int what)
 		mutex_unlock(&pmc_reserve_mutex);
 	}
 
+out:
 	atomic_inc(&active_events);
 	return 0;
 
@@ -398,11 +399,15 @@ int x86_add_exclusive(unsigned int what)
 
 void x86_del_exclusive(unsigned int what)
 {
+	atomic_dec(&active_events);
+
+	/*
+	 * See the comment in x86_add_exclusive().
+	 */
 	if (x86_pmu.lbr_pt_coexist && what == x86_lbr_exclusive_pt)
 		return;
 
 	atomic_dec(&x86_pmu.lbr_exclusive[what]);
-	atomic_dec(&active_events);
 }
 
 int x86_setup_perfctr(struct perf_event *event)
@@ -1642,9 +1647,12 @@ static struct attribute_group x86_pmu_format_group __ro_after_init = {
 
 ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page)
 {
-	struct perf_pmu_events_attr *pmu_attr = \
+	struct perf_pmu_events_attr *pmu_attr =
 		container_of(attr, struct perf_pmu_events_attr, attr);
-	u64 config = x86_pmu.event_map(pmu_attr->id);
+	u64 config = 0;
+
+	if (pmu_attr->id < x86_pmu.max_events)
+		config = x86_pmu.event_map(pmu_attr->id);
 
 	/* string trumps id */
 	if (pmu_attr->event_str)
@@ -1713,6 +1721,9 @@ is_visible(struct kobject *kobj, struct attribute *attr, int idx)
 {
 	struct perf_pmu_events_attr *pmu_attr;
 
+	if (idx >= x86_pmu.max_events)
+		return 0;
+
 	pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr);
 	/* str trumps id */
 	return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0;
diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
index 38de4a7f6752..6a3b599ee0fe 100644
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -63,9 +63,17 @@ struct bts_buffer {
 
 static struct pmu bts_pmu;
 
+static int buf_nr_pages(struct page *page)
+{
+	if (!PagePrivate(page))
+		return 1;
+
+	return 1 << page_private(page);
+}
+
 static size_t buf_size(struct page *page)
 {
-	return 1 << (PAGE_SHIFT + page_private(page));
+	return buf_nr_pages(page) * PAGE_SIZE;
 }
 
 static void *
@@ -83,9 +91,7 @@ bts_buffer_setup_aux(struct perf_event *event, void **pages,
 	/* count all the high order buffers */
 	for (pg = 0, nbuf = 0; pg < nr_pages;) {
 		page = virt_to_page(pages[pg]);
-		if (WARN_ON_ONCE(!PagePrivate(page) && nr_pages > 1))
-			return NULL;
-		pg += 1 << page_private(page);
+		pg += buf_nr_pages(page);
 		nbuf++;
 	}
 
@@ -109,7 +115,7 @@ bts_buffer_setup_aux(struct perf_event *event, void **pages,
 		unsigned int __nr_pages;
 
 		page = virt_to_page(pages[pg]);
-		__nr_pages = PagePrivate(page) ? 1 << page_private(page) : 1;
+		__nr_pages = buf_nr_pages(page);
 		buf->buf[nbuf].page = page;
 		buf->buf[nbuf].offset = offset;
 		buf->buf[nbuf].displacement = (pad ? BTS_RECORD_SIZE - pad : 0);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4ff86d57f9e5..a1f8bde19b56 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10523,7 +10523,7 @@ static struct pmu *perf_init_event(struct perf_event *event)
 		goto unlock;
 	}
 
-	list_for_each_entry_rcu(pmu, &pmus, entry) {
+	list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
 		ret = perf_try_init_event(pmu, event);
 		if (!ret)
 			goto unlock;