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 A692624C062; Wed, 5 Mar 2025 17:10:27 +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=1741194630; cv=none; b=V8s2FUtHOzd3JL2DmAsl2iuo4S9RjSHqY/E8cQd9iGQE9a7h3MmfDpsWsC1aZ74Nrt5vj25jcMLk6QsPhmZEmj2JTAe/AL6GvBds2+OvShtqQV5hPt5IRpySt6MV9vfakk9i9xQPJn/C53DjsrzHifGuU2vWzvb1eCoQxv+UXLM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741194630; c=relaxed/simple; bh=c7Q5onhWsSDWAX2jLrf0Ra38TOsQ0z+XcvaFQ0m/W/I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RJ0ScUqB5fwKf59KOQQuSUtOgCrdP08v0SO/M9fHzvuVD60kE58MyX3UYTQf5b+Bb69993JaS1qm57a2rcGHgoGCHw+tQuvNV5y98uyaY/+FnuEJVHKSeHp+DtlEs9+CuA5QzMmkzC6ca0nQb+jT0JemcNCFBfxXtDddhsPBAFs= 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 EF9EEFEC; Wed, 5 Mar 2025 09:10:39 -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 BD4223F66E; Wed, 5 Mar 2025 09:10:25 -0800 (PST) Date: Wed, 5 Mar 2025 17:10:16 +0000 From: Cristian Marussi To: Alice Ryhl Cc: Sudeep Holla , Cristian Marussi , linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [Bug report] Memory leak in scmi_device_create Message-ID: References: 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=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Mar 05, 2025 at 11:59:58AM +0000, Alice Ryhl wrote: > Dear SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE (SCPI/SCMI) Message > Protocol drivers maintainers, > > I flashed a v6.13-rc3 kernel onto a Rock5B board and noticed the > following output in my terminal: > > [ 687.694465] kmemleak: 4 new suspected memory leaks (see /sys/kernel/debug/kmemleak) > > It seems that there is a memory leak for devices created with > scmi_device_create. > ` Hi Alice, thanks for this report. > This was with a kernel running v6.13-rc3, but as far as I can tell, no > relevant changes have landed since v6.13-rc3. My tree *does* include > commit 295416091e44 ("firmware: arm_scmi: Fix slab-use-after-free in > scmi_bus_notifier()"). I've only seen this kmemleak report once, so it's > not happening consistently. > > See below for the full kmemleak report. > > Alice > > $ sudo cat /sys/kernel/debug/kmemleak > unreferenced object 0xffffff8106c86000 (size 2048): > comm "swapper/0", pid 1, jiffies 4294893094 > hex dump (first 32 bytes): > 02 00 00 00 10 00 00 00 c0 01 bc 03 81 ff ff ff ................ > 60 67 ba 03 81 ff ff ff 18 60 c8 06 81 ff ff ff `g.......`...... > backtrace (crc feae9680): > [<00000000197aa008>] kmemleak_alloc+0x34/0xa0 > [<0000000056fe02c9>] __kmalloc_cache_noprof+0x1e0/0x450 > [<00000000a8b3dfe1>] __scmi_device_create+0xb4/0x2b4 > [<000000008714917b>] scmi_device_create+0x40/0x194 > [<000000001818f3cf>] scmi_chan_setup+0x144/0x3b8 > [<00000000970bad38>] scmi_probe+0x584/0xa78 > [<000000002600d2fd>] platform_probe+0xbc/0xf0 > [<00000000f6f556b4>] really_probe+0x1b8/0x520 > [<00000000eed93d59>] __driver_probe_device+0xe0/0x1d8 > [<00000000d613b754>] driver_probe_device+0x6c/0x208 > [<00000000187a9170>] __driver_attach+0x168/0x328 > [<00000000e3ff1834>] bus_for_each_dev+0x14c/0x178 > [<00000000984a3176>] driver_attach+0x34/0x44 > [<00000000fc35bf2a>] bus_add_driver+0x1bc/0x358 > [<00000000747fce19>] driver_register+0xc0/0x1a0 > [<0000000081cb8754>] __platform_driver_register+0x40/0x50 > unreferenced object 0xffffff8103bc01c0 (size 32): I could not reproduce on my setup, even though I run a system with all the existent SCMI protocols (and related drivers) enabled (and so a lot of device creations) and a downstream test driver that causes even more SCMI devices to be created/destroyed at load/unload. Coming down the path from scmi_chan_setup(), it seems something around transport devices creation, but it is not obvious to me where the leak could hide.... ...any particular setup on your side ? ...using LKMs, loading/unloading, any usage pattern that could help me reproduce ? Thanks, Cristian