Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755219AbcK1UBD (ORCPT ); Mon, 28 Nov 2016 15:01:03 -0500 Received: from p3plsmtps2ded01.prod.phx3.secureserver.net ([208.109.80.58]:54014 "EHLO p3plsmtps2ded01.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755041AbcK1T4q (ORCPT ); Mon, 28 Nov 2016 14:56:46 -0500 x-originating-ip: 72.167.245.219 From: Matthew Wilcox 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" 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> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1480369871-5271-1-git-send-email-mawilcox@linuxonhyperv.com> References: <1480369871-5271-1-git-send-email-mawilcox@linuxonhyperv.com> X-CMAE-Envelope: MS4wfCYI7bRM92+0QvlKBCl1NYkj2eyh46iZ8o3nxTAbtMHWw7gdqHkjSn8T7OoUzjyys55AicBrGGd1p9EXjMMaDeo5mCerVLZqHHwJ9//ZXEHaOf2hHv0c tC8pnz048mnJp9x80q+nNAGRnU7geNQlS1B3pdz/gb9tPop3faNOCnxXRlgxNMnfU+gvcGWBbkobpdbC6BK8ph0w1x1rd5GSYPXzcstiGN93jh0i3KecIm1e e0YCpzGCtciFBm/dg21UYJkE0BrChK/M7sUzaRA5mc7S7+O5Vq0SmAMkhenOTjDVmPGUkmuZuAgWUu51i+ZDgp0f+koyohC44pESRuq1zjMOGWP4h86y/6rs v1fM/DCtaULWtjbDZwQXV50y70/QmzvF5MIBbr/EzBoFBR2P94JU61wRK5U4Lao8TZdf/ROGcJGY0SXDZ15VGwiJAowMTdMa1CAslXtFHK343TNr/90= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2553 Lines: 111 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