Messages in this thread Patch in this message | | | From | Matthew Wilcox <> | Subject | [PATCH 19/29] radix tree test suite: iteration test misuses RCU | Date | Wed, 16 Nov 2016 16:17:22 -0800 |
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From: Matthew Wilcox <mawilcox@microsoft.com>
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 <mawilcox@microsoft.com> --- 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
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