From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BAFEE191461; Fri, 7 Mar 2025 09:39:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741340387; cv=none; b=j7PlX/xqwcoxySoILHbG4hsLVO9AZinzfV+vf+33C8Ci+oFFLnnCGjFHPQ7rK8vs+TeJ65h06aOIGVQy+ol2Mx0J0t0ZIAc/p+Vj6nSZPtfKfBIr+arX16LbO6Y/04kOa5qqw+8QKCszn2u/HxUJ59mbOZO/ziiumsVTRlDAAQ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741340387; c=relaxed/simple; bh=erzpsiMOtlrYBxd+7HW4avLKiPxeS/41DggWsa42pHg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jRiGyx78pJhCSTGlOtEwtNFSnqweU7zZ3kI+vo01jS3AaFE8rPhQ4X/QUey2o+Szx7BZ2igeS36cG9UJ4bkGVJkuLE7dc/HXBkkcDbLtMhmhhN3RP1sse3lbVGfDvFDR5tLSh7WfcCeTHQR00cTT51CvZe/oGapKt4rqZim8dm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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> Precedence: bulk X-Mailing-List: arm-scmi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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