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From: tip-bot for Namhyung Kim <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: hbathini@linux.vnet.ibm.com, mingo@kernel.org,
	namhyung@kernel.org, acme@redhat.com,
	linux-kernel@vger.kernel.org, kjlx@templeofstupid.com,
	jolsa@redhat.com, tglx@linutronix.de, hpa@zytor.com
Subject: [tip:perf/urgent] perf namespace: Protect reading thread's namespace
Date: Tue, 28 May 2019 14:27:37 -0700	[thread overview]
Message-ID: <tip-6584140ba9e6762dd7ec73795243289b914f31f9@git.kernel.org> (raw)
In-Reply-To: <20190522053250.207156-2-namhyung@kernel.org>

Commit-ID:  6584140ba9e6762dd7ec73795243289b914f31f9
Gitweb:     https://git.kernel.org/tip/6584140ba9e6762dd7ec73795243289b914f31f9
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Wed, 22 May 2019 14:32:48 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 28 May 2019 09:52:23 -0300

perf namespace: Protect reading thread's namespace

It seems that the current code lacks holding the namespace lock in
thread__namespaces().  Otherwise it can see inconsistent results.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Krister Johansen <kjlx@templeofstupid.com>
Link: http://lkml.kernel.org/r/20190522053250.207156-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/thread.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 403045a2bbea..b413ba5b9835 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -133,7 +133,7 @@ void thread__put(struct thread *thread)
 	}
 }
 
-struct namespaces *thread__namespaces(const struct thread *thread)
+static struct namespaces *__thread__namespaces(const struct thread *thread)
 {
 	if (list_empty(&thread->namespaces_list))
 		return NULL;
@@ -141,10 +141,21 @@ struct namespaces *thread__namespaces(const struct thread *thread)
 	return list_first_entry(&thread->namespaces_list, struct namespaces, list);
 }
 
+struct namespaces *thread__namespaces(const struct thread *thread)
+{
+	struct namespaces *ns;
+
+	down_read((struct rw_semaphore *)&thread->namespaces_lock);
+	ns = __thread__namespaces(thread);
+	up_read((struct rw_semaphore *)&thread->namespaces_lock);
+
+	return ns;
+}
+
 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
 				    struct namespaces_event *event)
 {
-	struct namespaces *new, *curr = thread__namespaces(thread);
+	struct namespaces *new, *curr = __thread__namespaces(thread);
 
 	new = namespaces__new(event);
 	if (!new)

  parent reply	other threads:[~2019-05-28 21:27 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-22  5:32 [PATCH 0/3] perf tools: Assorted fixes and cleanups for namespace events Namhyung Kim
2019-05-22  5:32 ` [PATCH 1/3] perf tools: Protect reading thread's namespace Namhyung Kim
2019-05-22 13:18   ` Arnaldo Carvalho de Melo
2019-05-23  2:36     ` Namhyung Kim
2019-05-27  6:11       ` [PATCH 4/3] perf tools: Remove const from thread read accessors Namhyung Kim
2019-05-27 14:15         ` Arnaldo Carvalho de Melo
2019-05-30  8:07         ` [tip:perf/core] " tip-bot for Namhyung Kim
2019-05-28 21:27   ` tip-bot for Namhyung Kim [this message]
2019-05-22  5:32 ` [PATCH 2/3] perf tools: Add missing swap ops for namespace events Namhyung Kim
2019-05-22 13:23   ` Arnaldo Carvalho de Melo
2019-05-28 21:28   ` [tip:perf/urgent] perf session: " tip-bot for Namhyung Kim
2019-05-22  5:32 ` [PATCH 3/3] perf top: Enable --namespaces option Namhyung Kim
2019-05-22 13:24   ` Arnaldo Carvalho de Melo
2019-05-23  2:42     ` Namhyung Kim
2019-05-30  8:06   ` [tip:perf/core] perf top: Add " tip-bot for Namhyung Kim

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