From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f197.google.com (mail-io0-f197.google.com [209.85.223.197]) by kanga.kvack.org (Postfix) with ESMTP id B55D26B0273 for ; Mon, 28 Nov 2016 14:56:39 -0500 (EST) Received: by mail-io0-f197.google.com with SMTP id j65so260855529iof.1 for ; Mon, 28 Nov 2016 11:56:39 -0800 (PST) Received: from p3plsmtps2ded01.prod.phx3.secureserver.net (p3plsmtps2ded01.prod.phx3.secureserver.net. [208.109.80.58]) by mx.google.com with ESMTPS id m76si41571665iod.253.2016.11.28.11.56.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Nov 2016 11:56:39 -0800 (PST) From: Matthew Wilcox Subject: [PATCH v3 07/33] radix tree test suite: iteration test misuses RCU Date: Mon, 28 Nov 2016 13:50:45 -0800 Message-Id: <1480369871-5271-42-git-send-email-mawilcox@linuxonhyperv.com> In-Reply-To: <1480369871-5271-1-git-send-email-mawilcox@linuxonhyperv.com> References: <1480369871-5271-1-git-send-email-mawilcox@linuxonhyperv.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, Andrew Morton , Konstantin Khlebnikov , Ross Zwisler Cc: Matthew Wilcox , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, "Kirill A . Shutemov" From: Matthew Wilcox Each thread needs to register itself with RCU, otherwise the reading thread's read lock has no effect and the freeing thread will free the memory in the tree without waiting for the read lock to be dropped. Signed-off-by: Matthew Wilcox --- tools/testing/radix-tree/iteration_check.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/tools/testing/radix-tree/iteration_check.c b/tools/testing/radix-tree/iteration_check.c index 11d570c..df71cb8 100644 --- a/tools/testing/radix-tree/iteration_check.c +++ b/tools/testing/radix-tree/iteration_check.c @@ -29,6 +29,8 @@ static void *add_entries_fn(void *arg) { int pgoff; + rcu_register_thread(); + while (!test_complete) { for (pgoff = 0; pgoff < 100; pgoff++) { pthread_mutex_lock(&tree_lock); @@ -38,6 +40,8 @@ static void *add_entries_fn(void *arg) } } + rcu_unregister_thread(); + return NULL; } @@ -53,6 +57,8 @@ static void *tagged_iteration_fn(void *arg) struct radix_tree_iter iter; void **slot; + rcu_register_thread(); + while (!test_complete) { rcu_read_lock(); radix_tree_for_each_tagged(slot, &tree, &iter, 0, TAG) { @@ -72,12 +78,18 @@ static void *tagged_iteration_fn(void *arg) continue; } - if (rand_r(&seeds[0]) % 50 == 0) + if (rand_r(&seeds[0]) % 50 == 0) { slot = radix_tree_iter_next(&iter); + rcu_read_unlock(); + rcu_barrier(); + rcu_read_lock(); + } } rcu_read_unlock(); } + rcu_unregister_thread(); + return NULL; } @@ -93,6 +105,8 @@ static void *untagged_iteration_fn(void *arg) struct radix_tree_iter iter; void **slot; + rcu_register_thread(); + while (!test_complete) { rcu_read_lock(); radix_tree_for_each_slot(slot, &tree, &iter, 0) { @@ -112,12 +126,18 @@ static void *untagged_iteration_fn(void *arg) continue; } - if (rand_r(&seeds[1]) % 50 == 0) + if (rand_r(&seeds[1]) % 50 == 0) { slot = radix_tree_iter_next(&iter); + rcu_read_unlock(); + rcu_barrier(); + rcu_read_lock(); + } } rcu_read_unlock(); } + rcu_unregister_thread(); + return NULL; } @@ -127,6 +147,8 @@ static void *untagged_iteration_fn(void *arg) */ static void *remove_entries_fn(void *arg) { + rcu_register_thread(); + while (!test_complete) { int pgoff; @@ -137,6 +159,8 @@ static void *remove_entries_fn(void *arg) pthread_mutex_unlock(&tree_lock); } + rcu_unregister_thread(); + return NULL; } -- 2.10.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org