From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net [217.70.183.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 64BE052F7A; Thu, 29 Feb 2024 08:40:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709196016; cv=none; b=BDr92UaePWEz1IwrmGYnMiKaNDBdVeGHM11c9kuc76nbDmRI6e8bPxdsIdUTW9Bih8sSyreekt7gATfPUedMCZwFwtGUwNK0lDecUp18l+c/msIR1u07emw5D8qmzvT+rEQq7cnTJTHL+8MKryLSoddgEXA7mvWWluz3gVj/mMY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709196016; c=relaxed/simple; bh=BNo0yW2FLpDKUhmP2HaX0f6PbcoTDWSkMT1gkxmdvZE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Sg1aihYy/QGL/SFRSX2cWUBx9z5n2TEOiXlv7rSU6giXyohssBUDBbhE1jKhBwXRSWKCTWEbaTXHnPmcS8n67Cjs/5hGwvlJbSJ76LmYIUDP25q7Y6hf1b+fOln9DC6sDvUt9677wBgrKhPfgZB4OkV4Bb+UTqljvfJJSeSRPPs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=fdbcXAaE; arc=none smtp.client-ip=217.70.183.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="fdbcXAaE" Received: by mail.gandi.net (Postfix) with ESMTPA id B5F541C000E; Thu, 29 Feb 2024 08:40:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1709196011; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=66l5nnX2XD0JkszxdbTNgnTBzOtV2bLUDTMkK3+nFE4=; b=fdbcXAaEGmYq4xDjfNLLpoZfYjl0yLzw91HYvMXGM0Rk7GIahIpgp/PD8MJc3XtdCCD8ft Dyhg2CLbB3DE0DI8tN1a8oFnq3ncDc7RYM3otb43Lx1iGdfxJ4CuAEdSi8LhLsC2grptbG xmgrXu97H663Qn08GdU3TNxJdkl1wzjIIQEd1UnEO6+E0eM3OOqMgaiRf2IvxBizQw5sf3 yNYGUc11/7MAAve97/BwKm+YVKBdBuqVOite+4ChfY3A5n5Q/dgOfEhmZEA3CYnPLDL07S 4XsnrlV07nBmPEDmyVmcI9qMU5+g3fU59+93KdCjyQj6GZsMB3BpbV/U2iyhzg== From: Herve Codina To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Rob Herring , Frank Rowand Cc: Lizhi Hou , Max Zhen , Sonal Santan , Stefano Stabellini , Jonathan Cameron , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Allan Nielsen , Horatiu Vultur , Steen Hegelund , Luca Ceresoli , Nuno Sa , Thomas Petazzoni , Herve Codina Subject: [PATCH v2 0/2] Synchronize DT overlay removal with devlink removals Date: Thu, 29 Feb 2024 09:39:40 +0100 Message-ID: <20240229083953.607569-1-herve.codina@bootlin.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-GND-Sasl: herve.codina@bootlin.com Hi, In the following sequence: of_platform_depopulate(); /* Remove devices from a DT overlay node */ of_overlay_remove(); /* Remove the DT overlay node itself */ Some warnings are raised by __of_changeset_entry_destroy() which was called from of_overlay_remove(): ERROR: memory leak, expected refcount 1 instead of 2 ... The issue is that, during the device devlink removals triggered from the of_platform_depopulate(), jobs are put in a workqueue. These jobs drop the reference to the devices. When a device is no more referenced (refcount == 0), it is released and the reference to its of_node is dropped by a call to of_node_put(). These operations are fully correct except that, because of the workqueue, they are done asynchronously with respect to function calls. In the sequence provided, the jobs are run too late, after the call to __of_changeset_entry_destroy() and so a missing of_node_put() call is detected by __of_changeset_entry_destroy(). This series fixes this issue introducing device_link_wait_removal() in order to wait for the end of jobs execution (patch 1) and using this function to synchronize the overlay removal with the end of jobs execution (patch 2). Compared to the previous iteration: https://lore.kernel.org/linux-kernel/20231130174126.688486-1-herve.codina@bootlin.com/ this v2 series mainly: - Renames the workqueue used. - Calls device_link_wait_removal() a bit later to handle cases reported by Luca [1] and Nuno [2]. [1]: https://lore.kernel.org/all/20231220181627.341e8789@booty/ [2]: https://lore.kernel.org/all/20240205-fix-device-links-overlays-v2-2-5344f8c79d57@analog.com/ Best regards, Hervé Changes v1 -> v2 - Patch 1 Rename the workqueue to 'device_link_wq' Add 'Fixes' tag and Cc stable - Patch 2 Add device.h inclusion. Call device_link_wait_removal() later in the overlay removal sequence (i.e. in free_overlay_changeset() function). Drop of_mutex lock while calling device_link_wait_removal(). Add 'Fixes' tag and Cc stable Herve Codina (2): driver core: Introduce device_link_wait_removal() of: overlay: Synchronize of_overlay_remove() with the devlink removals drivers/base/core.c | 26 +++++++++++++++++++++++--- drivers/of/overlay.c | 9 ++++++++- include/linux/device.h | 1 + 3 files changed, 32 insertions(+), 4 deletions(-) -- 2.43.0