From: Namhyung Kim <namhyung@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
Krister Johansen <kjlx@templeofstupid.com>,
Hari Bathini <hbathini@linux.vnet.ibm.com>
Subject: Re: [PATCH 1/3] perf tools: Protect reading thread's namespace
Date: Thu, 23 May 2019 11:36:38 +0900 [thread overview]
Message-ID: <20190523023636.GA196218@google.com> (raw)
In-Reply-To: <20190522131832.GB30271@kernel.org>
Hi Arnaldo,
On Wed, May 22, 2019 at 10:18:32AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 22, 2019 at 02:32:48PM +0900, Namhyung Kim escreveu:
> > 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>
> > ---
> > 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);
> > +
>
> Humm, so we need to change thread__namespaces() to remove that const
> instead of throwing it away with that cast, right?
Yes, that's possible too. Note that thread__comm_str() has the same issue
as well.
Thanks,
Namhyung
next prev parent reply other threads:[~2019-05-23 2:36 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 [this message]
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:perf/urgent] perf namespace: Protect reading thread's namespace tip-bot for Namhyung Kim
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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