From 8314019f660cd28fc8cdb634f82b437105074258 Mon Sep 17 00:00:00 2001 From: Ryan Dwyer Date: Thu, 2 Aug 2018 20:54:03 +1000 Subject: [PATCH] Fix race condition crashes when unmapping views This fixes two issues which were both introduced in #2396. First issue: The PR changes the location of the buffer save to transaction_apply, but puts it inside the should_configure block. For unmapping (destroying) views, should_configure returns false so it wasn't saving the buffer. If a frame was rendered between the unmap and the transaction applying then it would result in a crash. Second issue: If a destroying view is involved in two transactions, we must not release the buffer between the transactions because there is no live buffer to grab any more. --- sway/desktop/transaction.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/sway/desktop/transaction.c b/sway/desktop/transaction.c index 94070363..4e6af86a 100644 --- a/sway/desktop/transaction.c +++ b/sway/desktop/transaction.c @@ -195,11 +195,18 @@ static void transaction_apply(struct sway_transaction *transaction) { sizeof(struct sway_container_state)); if (container->type == C_VIEW) { - if (container->sway_view->saved_buffer) { - view_remove_saved_buffer(container->sway_view); - } - if (container->instructions->length > 1) { - view_save_buffer(container->sway_view); + if (container->destroying) { + if (container->instructions->length == 1 && + container->sway_view->saved_buffer) { + view_remove_saved_buffer(container->sway_view); + } + } else { + if (container->sway_view->saved_buffer) { + view_remove_saved_buffer(container->sway_view); + } + if (container->instructions->length > 1) { + view_save_buffer(container->sway_view); + } } } } @@ -276,9 +283,9 @@ static void transaction_commit(struct sway_transaction *transaction) { // mapping and its default geometry doesn't intersect an output. struct timespec when; wlr_surface_send_frame_done(con->sway_view->surface, &when); - if (!con->sway_view->saved_buffer) { - view_save_buffer(con->sway_view); - } + } + if (con->type == C_VIEW && !con->sway_view->saved_buffer) { + view_save_buffer(con->sway_view); } list_add(con->instructions, instruction); }