linux-kernel - [tip:perf/urgent] perf/x86/cqm: Fix CQM memory leak and notifier leak

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Date:	Mon, 21 Mar 2016 02:51:53 -0700
From:	tip-bot for Vikas Shivappa <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, brgerst@...il.com,
	namhyung@...nel.org, tony.luck@...el.com, vincent.weaver@...ne.edu,
	jolsa@...hat.com, vikas.shivappa@...ux.intel.com, acme@...hat.com,
	hpa@...or.com, dsahern@...il.com, luto@...capital.net,
	bp@...en8.de, tglx@...utronix.de, matt@...eblueprint.co.uk,
	peterz@...radead.org, linux-kernel@...r.kernel.org,
	mingo@...nel.org, eranian@...gle.com,
	alexander.shishkin@...ux.intel.com, dvlasenk@...hat.com
Subject: [tip:perf/urgent] perf/x86/cqm: Fix CQM memory leak and notifier
 leak

Commit-ID:  ada2f634cd50d050269b67b4e2966582387e7c27
Gitweb:     http://git.kernel.org/tip/ada2f634cd50d050269b67b4e2966582387e7c27
Author:     Vikas Shivappa <vikas.shivappa@...ux.intel.com>
AuthorDate: Thu, 10 Mar 2016 15:32:08 -0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 21 Mar 2016 09:08:19 +0100

perf/x86/cqm: Fix CQM memory leak and notifier leak

Fixes the hotcpu notifier leak and other global variable memory leaks
during CQM (cache quality of service monitoring) initialization.

Signed-off-by: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Tony Luck <tony.luck@...el.com>
Acked-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Matt Fleming <matt@...eblueprint.co.uk>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Vince Weaver <vincent.weaver@...ne.edu>
Cc: fenghua.yu@...el.com
Cc: h.peter.anvin@...el.com
Cc: ravi.v.shankar@...el.com
Cc: vikas.shivappa@...el.com
Link: http://lkml.kernel.org/r/1457652732-4499-3-git-send-email-vikas.shivappa@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/events/intel/cqm.c | 43 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 32 insertions(+), 11 deletions(-)

diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c
index b0226f1..dbb058d 100644
--- a/arch/x86/events/intel/cqm.c
+++ b/arch/x86/events/intel/cqm.c
@@ -211,6 +211,20 @@ static void __put_rmid(u32 rmid)
 	list_add_tail(&entry->list, &cqm_rmid_limbo_lru);
 }
 
+static void cqm_cleanup(void)
+{
+	int i;
+
+	if (!cqm_rmid_ptrs)
+		return;
+
+	for (i = 0; i < cqm_max_rmid; i++)
+		kfree(cqm_rmid_ptrs[i]);
+
+	kfree(cqm_rmid_ptrs);
+	cqm_rmid_ptrs = NULL;
+}
+
 static int intel_cqm_setup_rmid_cache(void)
 {
 	struct cqm_rmid_entry *entry;
@@ -218,7 +232,7 @@ static int intel_cqm_setup_rmid_cache(void)
 	int r = 0;
 
 	nr_rmids = cqm_max_rmid + 1;
-	cqm_rmid_ptrs = kmalloc(sizeof(struct cqm_rmid_entry *) *
+	cqm_rmid_ptrs = kzalloc(sizeof(struct cqm_rmid_entry *) *
 				nr_rmids, GFP_KERNEL);
 	if (!cqm_rmid_ptrs)
 		return -ENOMEM;
@@ -249,11 +263,9 @@ static int intel_cqm_setup_rmid_cache(void)
 	mutex_unlock(&cache_mutex);
 
 	return 0;
-fail:
-	while (r--)
-		kfree(cqm_rmid_ptrs[r]);
 
-	kfree(cqm_rmid_ptrs);
+fail:
+	cqm_cleanup();
 	return -ENOMEM;
 }
 
@@ -1312,7 +1324,7 @@ static const struct x86_cpu_id intel_cqm_match[] = {
 
 static int __init intel_cqm_init(void)
 {
-	char *str, scale[20];
+	char *str = NULL, scale[20];
 	int i, cpu, ret;
 
 	if (!x86_match_cpu(intel_cqm_match))
@@ -1372,16 +1384,25 @@ static int __init intel_cqm_init(void)
 		cqm_pick_event_reader(i);
 	}
 
-	__perf_cpu_notifier(intel_cqm_cpu_notifier);
-
 	ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1);
-	if (ret)
+	if (ret) {
 		pr_err("Intel CQM perf registration failed: %d\n", ret);
-	else
-		pr_info("Intel CQM monitoring enabled\n");
+		goto out;
+	}
 
+	pr_info("Intel CQM monitoring enabled\n");
+
+	/*
+	 * Register the hot cpu notifier once we are sure cqm
+	 * is enabled to avoid notifier leak.
+	 */
+	__perf_cpu_notifier(intel_cqm_cpu_notifier);
 out:
 	cpu_notifier_register_done();
+	if (ret) {
+		kfree(str);
+		cqm_cleanup();
+	}
 
 	return ret;
 }