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From: Bart Van Assche <bvanassche@acm.org>
To: mingo@redhat.com
Cc: peterz@infradead.org, tj@kernel.org, longman@redhat.com,
	johannes.berg@intel.com, linux-kernel@vger.kernel.org,
	Bart Van Assche <bvanassche@acm.org>,
	Johannes Berg <johannes@sipsolutions.net>
Subject: [PATCH v3 12/24] locking/lockdep: Make concurrent lockdep_reset_lock() calls safe
Date: Thu,  6 Dec 2018 17:11:36 -0800	[thread overview]
Message-ID: <20181207011148.251812-13-bvanassche@acm.org> (raw)
In-Reply-To: <20181207011148.251812-1-bvanassche@acm.org>

Since zap_class() removes items from the all_lock_classes list and the
classhash_table, protect all zap_class() calls against concurrent
data structure modifications with the graph lock.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 kernel/locking/lockdep.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 346b5a1fd062..737d2dd3ea56 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4122,6 +4122,9 @@ void lockdep_reset(void)
 	raw_local_irq_restore(flags);
 }
 
+/*
+ * Remove all references to a lock class. The caller must hold the graph lock.
+ */
 static void zap_class(struct lock_class *class)
 {
 	int i;
@@ -4229,6 +4232,7 @@ void lockdep_reset_lock(struct lockdep_map *lock)
 	int j, locked;
 
 	raw_local_irq_save(flags);
+	locked = graph_lock();
 
 	/*
 	 * Remove all classes this lock might have:
@@ -4245,7 +4249,6 @@ void lockdep_reset_lock(struct lockdep_map *lock)
 	 * Debug check: in the end all mapped classes should
 	 * be gone.
 	 */
-	locked = graph_lock();
 	if (unlikely(lock_class_cache_is_registered(lock))) {
 		if (debug_locks_off_graph_unlock()) {
 			/*
-- 
2.20.0.rc2.403.gdbc3b29805-goog


  parent reply	other threads:[~2018-12-07  1:14 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-07  1:11 [PATCH v3 00/24] locking/lockdep: Add support for dynamic keys Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 01/24] lockdep tests: Display compiler warning and error messages Bart Van Assche
2018-12-11 15:22   ` [tip:locking/core] tools/lib/lockdep/tests: " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 02/24] lockdep tests: Fix shellcheck warnings Bart Van Assche
2018-12-11 15:23   ` [tip:locking/core] tools/lib/lockdep/tests: " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 03/24] lockdep tests: Improve testing accuracy Bart Van Assche
2018-12-11 15:23   ` [tip:locking/core] tools/lib/lockdep/tests: " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 04/24] lockdep tests: Run lockdep tests a second time under Valgrind Bart Van Assche
2018-12-11 15:24   ` [tip:locking/core] tools/lib/lockdep/tests: " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 05/24] liblockdep: Rename "trywlock" into "trywrlock" Bart Van Assche
2018-12-11 15:24   ` [tip:locking/core] tools/lib/lockdep: " tip-bot for Bart Van Assche
2018-12-11 17:19   ` [PATCH v3 05/24] liblockdep: " Sasha Levin
2018-12-11 17:38     ` Bart Van Assche
2018-12-13 19:41       ` Sasha Levin
2018-12-07  1:11 ` [PATCH v3 06/24] liblockdep: Add dummy print_irqtrace_events() implementation Bart Van Assche
2018-12-11 15:25   ` [tip:locking/core] tools/lib/lockdep: " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 07/24] lockdep tests: Test the lockdep_reset_lock() implementation Bart Van Assche
2018-12-11 15:26   ` [tip:locking/core] tools/lib/lockdep/tests: " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 08/24] locking/lockdep: Declare local symbols static Bart Van Assche
2018-12-11 15:26   ` [tip:locking/core] " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 09/24] locking/lockdep: Inline __lockdep_init_map() Bart Van Assche
2018-12-11 15:27   ` [tip:locking/core] " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 10/24] locking/lockdep: Introduce lock_class_cache_is_registered() Bart Van Assche
2018-12-11 15:27   ` [tip:locking/core] " tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 11/24] locking/lockdep: Remove a superfluous INIT_LIST_HEAD() statement Bart Van Assche
2018-12-11 15:28   ` [tip:locking/core] " tip-bot for Bart Van Assche
2018-12-07  1:11 ` Bart Van Assche [this message]
2018-12-11 15:29   ` [tip:locking/core] locking/lockdep: Make concurrent lockdep_reset_lock() calls safe tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 13/24] locking/lockdep: Stop using RCU primitives to access all_lock_classes Bart Van Assche
2018-12-11 15:29   ` [tip:locking/core] locking/lockdep: Stop using RCU primitives to access 'all_lock_classes' tip-bot for Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 14/24] locking/lockdep: Make zap_class() remove all matching lock order entries Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 15/24] locking/lockdep: Reorder struct lock_class members Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 16/24] locking/lockdep: Retain the class key and name while freeing a lock class Bart Van Assche
2018-12-07 10:21   ` Peter Zijlstra
2018-12-07 14:50     ` Waiman Long
2018-12-07 16:23       ` Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 17/24] locking/lockdep: Free lock classes that are no longer in use Bart Van Assche
2018-12-07 12:14   ` Peter Zijlstra
2018-12-07 16:27     ` Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 18/24] locking/lockdep: Reuse list entries " Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 19/24] locking/lockdep: Check data structure consistency Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 20/24] locking/lockdep: Introduce __lockdep_free_key_range() Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 21/24] locking/lockdep: Verify whether lock objects are small enough to be used as class keys Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 22/24] locking/lockdep: Add support for dynamic keys Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 23/24] kernel/workqueue: Use dynamic lockdep keys for workqueues Bart Van Assche
2018-12-07  1:11 ` [PATCH v3 24/24] lockdep tests: Test dynamic key registration Bart Van Assche
2018-12-07 12:23 ` [PATCH v3 00/24] locking/lockdep: Add support for dynamic keys Peter Zijlstra
2018-12-07 16:35   ` Bart Van Assche
2018-12-08 10:26     ` Peter Zijlstra

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