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From: tip-bot for Peter Zijlstra <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: acme@kernel.org, mingo@kernel.org, linux-kernel@vger.kernel.org,
	torvalds@linux-foundation.org, peterz@infradead.org,
	tglx@linutronix.de, hpa@zytor.com
Subject: [tip:perf/core] perf: Add a bit of paranoia
Date: Wed, 4 Feb 2015 06:39:01 -0800	[thread overview]
Message-ID: <tip-652884fe0c7bd57f534c5fe68d6def0dc8c4b7ed@git.kernel.org> (raw)
In-Reply-To: <20150123125834.150481799@infradead.org>

Commit-ID:  652884fe0c7bd57f534c5fe68d6def0dc8c4b7ed
Gitweb:     http://git.kernel.org/tip/652884fe0c7bd57f534c5fe68d6def0dc8c4b7ed
Author:     Peter Zijlstra <peterz@infradead.org>
AuthorDate: Fri, 23 Jan 2015 11:20:10 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 4 Feb 2015 08:07:09 +0100

perf: Add a bit of paranoia

Add a few WARN()s to catch things that should never happen.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.150481799@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/events/core.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index b4a696c..b358cb3 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1275,6 +1275,8 @@ static void perf_group_attach(struct perf_event *event)
 	if (group_leader == event)
 		return;
 
+	WARN_ON_ONCE(group_leader->ctx != event->ctx);
+
 	if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
 			!is_software_event(event))
 		group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
@@ -1296,6 +1298,10 @@ static void
 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 {
 	struct perf_cpu_context *cpuctx;
+
+	WARN_ON_ONCE(event->ctx != ctx);
+	lockdep_assert_held(&ctx->lock);
+
 	/*
 	 * We can have double detach due to exit/hot-unplug + close.
 	 */
@@ -1380,6 +1386,8 @@ static void perf_group_detach(struct perf_event *event)
 
 		/* Inherit group flags from the previous leader */
 		sibling->group_flags = event->group_flags;
+
+		WARN_ON_ONCE(sibling->ctx != event->ctx);
 	}
 
 out:
@@ -1442,6 +1450,10 @@ event_sched_out(struct perf_event *event,
 {
 	u64 tstamp = perf_event_time(event);
 	u64 delta;
+
+	WARN_ON_ONCE(event->ctx != ctx);
+	lockdep_assert_held(&ctx->lock);
+
 	/*
 	 * An event which could not be activated because of
 	 * filter mismatch still needs to have its timings
@@ -7822,14 +7834,19 @@ static void perf_free_event(struct perf_event *event,
 
 	put_event(parent);
 
+	raw_spin_lock_irq(&ctx->lock);
 	perf_group_detach(event);
 	list_del_event(event, ctx);
+	raw_spin_unlock_irq(&ctx->lock);
 	free_event(event);
 }
 
 /*
- * free an unexposed, unused context as created by inheritance by
+ * Free an unexposed, unused context as created by inheritance by
  * perf_event_init_task below, used by fork() in case of fail.
+ *
+ * Not all locks are strictly required, but take them anyway to be nice and
+ * help out with the lockdep assertions.
  */
 void perf_event_free_task(struct task_struct *task)
 {

  parent reply	other threads:[~2015-02-04 14:39 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-23 12:51 [RFC][PATCH 0/3] perf fixes Peter Zijlstra
2015-01-23 12:52 ` [RFC][PATCH 1/3] perf: Tighten (and fix) the grouping condition Peter Zijlstra
2015-01-23 15:02   ` Mark Rutland
2015-01-23 15:07     ` Peter Zijlstra
2015-01-23 15:22       ` Mark Rutland
2015-02-04 12:59         ` Peter Zijlstra
2015-01-28 14:30   ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2015-01-23 12:52 ` [RFC][PATCH 2/3] perf: Add a bit of paranoia Peter Zijlstra
2015-01-26 16:26   ` Peter Zijlstra
2015-01-27 21:28     ` Vince Weaver
2015-01-29  2:16       ` Vince Weaver
2015-01-29  7:51         ` Jiri Olsa
2015-01-29 13:44           ` Peter Zijlstra
2015-02-04 14:39             ` [tip:perf/core] perf: Fix put_event() ctx lock tip-bot for Peter Zijlstra
2015-01-29 14:47     ` [RFC][PATCH 2/3] perf: Add a bit of paranoia Peter Zijlstra
2015-02-02  6:33       ` Vince Weaver
2015-02-02 15:42         ` Peter Zijlstra
2015-02-02 17:32           ` Peter Zijlstra
2015-02-04 14:51             ` Jiri Olsa
2015-02-04 16:33               ` Peter Zijlstra
2015-02-04 16:43                 ` Peter Zijlstra
2015-02-04 14:39     ` [tip:perf/core] perf: Fix move_group() order tip-bot for Peter Zijlstra (Intel)
2015-02-04 14:39   ` tip-bot for Peter Zijlstra [this message]
2015-01-23 12:52 ` [RFC][PATCH 3/3] perf: Fix event->ctx locking Peter Zijlstra
2015-02-04 14:39   ` [tip:perf/core] " tip-bot for Peter Zijlstra
2015-01-26 14:30 ` [RFC][PATCH 0/3] perf fixes Vince Weaver
2015-01-26 18:03   ` Vince Weaver
2015-01-26 18:34     ` Jiri Olsa
2015-01-26 18:52       ` Vince Weaver

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