From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 14675C19F32 for ; Fri, 7 Mar 2025 09:41:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=m0vprSm7UOHiqG2FrYoa9wbD3ONqT6FKCMoqyjM6UQI=; b=i5aTXo5j5UUqzupzgQykZCuG9f +cxkQt3delq5zpEvA9lopyzs7clQ1AjnGn5ornUOJ5zAVWjbkLO32rnPxpy9gvCyy06R1M51zwSQ6 7kCasFhbDPmVLZX6vA3kh0xRewkGHKJOuIU2FfX4rRl0MlFM8z1VXF+NIOzsQYXK0vBhjESlc8u9J L0YIIXOpfnVDZV+IU76JX1E9vwTU8n1dQX+LC1T/YMkeSEfAQ1utVk8blBlZVU7G/VZmpw2KsUnoQ 49KYiUHJXxMR9ssasMRuBj5adaiLh+3El9EBODPWVrEDJ/RHBB49fdK9g1lD/5IG74ztKOBIreHnH zx59qpKA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqUCt-0000000DkN7-0YLn; Fri, 07 Mar 2025 09:41:27 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqUBF-0000000DkHz-29s8 for linux-arm-kernel@lists.infradead.org; Fri, 07 Mar 2025 09:39:47 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A5C37150C; Fri, 7 Mar 2025 01:39:56 -0800 (PST) Received: from pluto (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EE8603F66E; Fri, 7 Mar 2025 01:39:42 -0800 (PST) Date: Fri, 7 Mar 2025 09:39:34 +0000 From: Cristian Marussi To: Alice Ryhl Cc: Cristian Marussi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, Sudeep Holla , Catalin Marinas Subject: Re: [PATCH] firmware: arm_scmi: Balance device refcount when destroying devices Message-ID: References: <20250306185447.2039336-1-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250307_013945_597800_9AE3AE5E X-CRM114-Status: GOOD ( 16.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Mar 07, 2025 at 09:34:15AM +0000, Alice Ryhl wrote: > On Thu, Mar 06, 2025 at 06:54:47PM +0000, Cristian Marussi wrote: > > Using device_find_child() to lookup the proper SCMI device to destroy > > causes an unbalance in device refcount, since device_find_child() calls an > > implicit get_device(): this, in turns, inhibits the call of the provided > > release methods upon devices destruction. > > > > As a consequence, one of the structures that is not freed properly upon > > destruction is the internal struct device_private dev->p populated by the > > drivers subsystem core. > > > > KMemleak detects this situation since loading/unloding some SCMI driver > > causes related devices to be created/destroyed without calling any > > device_release method. > > > > unreferenced object 0xffff00000f583800 (size 512): > > comm "insmod", pid 227, jiffies 4294912190 > > hex dump (first 32 bytes): > > 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... > > ff ff ff ff ff ff ff ff 60 36 1d 8a 00 80 ff ff ........`6...... > > backtrace (crc 114e2eed): > > kmemleak_alloc+0xbc/0xd8 > > __kmalloc_cache_noprof+0x2dc/0x398 > > device_add+0x954/0x12d0 > > device_register+0x28/0x40 > > __scmi_device_create.part.0+0x1bc/0x380 > > scmi_device_create+0x2d0/0x390 > > scmi_create_protocol_devices+0x74/0xf8 > > scmi_device_request_notifier+0x1f8/0x2a8 > > notifier_call_chain+0x110/0x3b0 > > blocking_notifier_call_chain+0x70/0xb0 > > scmi_driver_register+0x350/0x7f0 > > 0xffff80000a3b3038 > > do_one_initcall+0x12c/0x730 > > do_init_module+0x1dc/0x640 > > load_module+0x4b20/0x5b70 > > init_module_from_file+0xec/0x158 > > > > $ ./scripts/faddr2line ./vmlinux device_add+0x954/0x12d0 > > device_add+0x954/0x12d0: > > kmalloc_noprof at include/linux/slab.h:901 > > (inlined by) kzalloc_noprof at include/linux/slab.h:1037 > > (inlined by) device_private_init at drivers/base/core.c:3510 > > (inlined by) device_add at drivers/base/core.c:3561 > > > > Balance device refcount by issuing a put_device() on devices found via > > device_find_child(). > > > > Reported-by: Alice Ryhl > > Closes: https://lore.kernel.org/linux-arm-kernel/Z8nK3uFkspy61yjP@arm.com/T/#mc1f73a0ea5e41014fa145147b7b839fc988ada8f > > CC: Sudeep Holla > > CC: Catalin Marinas > > Fixes: d4f9dddd21f3 ("firmware: arm_scmi: Add dynamic scmi devices creation") > > Signed-off-by: Cristian Marussi > > I was not able to reproduce the memory leak after applying this patch. > > Tested-by: Alice Ryhl Thanks a lot for testing (and for the report) ! Cristian