From patchwork Fri Jan 7 12:55:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kieran Bingham X-Patchwork-Id: 15260 X-Patchwork-Delegate: kieran.bingham@ideasonboard.com Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id BFF20C325A for ; Fri, 7 Jan 2022 12:55:14 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 483BC608E6; Fri, 7 Jan 2022 13:55:13 +0100 (CET) Authentication-Results: lancelot.ideasonboard.com; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="J/p3E8y6"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 16F926091E for ; Fri, 7 Jan 2022 13:55:11 +0100 (CET) Received: from Monstersaurus.ksquared.org.uk.beta.tailscale.net (cpc89244-aztw30-2-0-cust3082.18-1.cable.virginm.net [86.31.172.11]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id B56FD11BB; Fri, 7 Jan 2022 13:55:10 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1641560110; bh=i20JeXHm30wC0P+xND/ZuoxhTyzcltGmvvWoMiRwLxM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J/p3E8y6Pk7yfOlYdvKjyzNI33SimLOOO8MqSRmallVNcVHdDs7wauRO73aOk8c9m m1LPggT/9pOZ4VnrRCCLOut5+bfFhmCGNW9rM84XTtGlgG5r+JQU/5oTA2brc3E8NO jGjGUOrnW3eDg8sD1QgghDcdf30Wne+QgZiVTy6g= From: Kieran Bingham To: libcamera devel Date: Fri, 7 Jan 2022 12:55:06 +0000 Message-Id: <20220107125506.1477795-3-kieran.bingham@ideasonboard.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220107125506.1477795-1-kieran.bingham@ideasonboard.com> References: <20220107125506.1477795-1-kieran.bingham@ideasonboard.com> MIME-Version: 1.0 Subject: [libcamera-devel] [PATCH 2/2] libcamera: base: signal: Prevent excessive slot usage X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" Slots are not expected to be connected to lots of signals. Our normal use case is a one to one mapping with a signal expected to call one slot. While we support multiple slots, excessive use is likely the result of a bug indicating a failure to disconnect slots or repeated connection of a slot which can lead to memory leaks and poor performance when deleting the Object. Assert that a maximum of 8 slots are connected which will catch any bug and still allow some multiple slot usage. If this limit is ever met it can be extended and considered at that time. Signed-off-by: Kieran Bingham Reviewed-by: Jacopo Mondi Tested-by: David Plowman --- Note that this patch causes the CTS tests to fail as they hit this assertion. It is not yet investigated if we really need more slots or if the assertion has already caught a slot-leak, but posting for early review anyway. src/libcamera/base/signal.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/libcamera/base/signal.cpp b/src/libcamera/base/signal.cpp index 9df45d079a42..7e6a23cc909d 100644 --- a/src/libcamera/base/signal.cpp +++ b/src/libcamera/base/signal.cpp @@ -7,6 +7,7 @@ #include +#include #include /** @@ -35,6 +36,13 @@ void SignalBase::connect(BoundMethodBase *slot) if (object) object->connect(this); slots_.push_back(slot); + + /* + * Slots are not expected to be used to connect many items. If we exceed + * a reasonable amount, presume that there is a bug and fail fast on + * debug builds. + */ + ASSERT(slots_.size() < 8); } void SignalBase::disconnect(Object *object)