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 93C38C282D1 for ; Thu, 6 Mar 2025 14:19:19 +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=9u/g5Sv9S270wjV6iCQUW19y+diRdBt2j8yIDmSJ5n8=; b=bKERdrZRopGOao5pHkJJY+4b0w vSvYbyxsen37W5jnFAhLRf3HsC3vR30pL6Bt33aaMkXXbIuK5C+LVGn+/KFGCZK46uL+rF7XQj4gh O+IJigdG9s+a1csY2PdubvVXpv4z45DRpap4UEspPk+A87/kGHWGLPtWs38ckRD7YzGq74O9thOf7 XsTVNGIlN2s9RIU6Vi0kYuXWAmJZevAoO6/rGALYy8452EP13oZv28OclwWAHSX0+Rf3YRdLgDR1e 03XGP08Wp8ORcN4fpwvaN0ruCXIPdZ+hUi+YNKXZbTL5f8IhpJeUg1zmgobbPx4XXoeoYBInsmcZY yvrEqlPg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqC3x-0000000BBKf-2cTS; Thu, 06 Mar 2025 14:19:01 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqAgM-0000000AyDE-4AmE for linux-arm-kernel@lists.infradead.org; Thu, 06 Mar 2025 12:50:36 +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 43E1E1007; Thu, 6 Mar 2025 04:50:47 -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 392143F673; Thu, 6 Mar 2025 04:50:33 -0800 (PST) Date: Thu, 6 Mar 2025 12:50:17 +0000 From: Cristian Marussi To: Alice Ryhl Cc: Cristian Marussi , Sudeep Holla , 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: 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-20250306_045035_141485_4D8CBE4F X-CRM114-Status: GOOD ( 32.45 ) 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 Thu, Mar 06, 2025 at 11:09:33AM +0000, Alice Ryhl wrote: > On Wed, Mar 05, 2025 at 05:10:16PM +0000, Cristian Marussi wrote: > > 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 ? > > I looked into this a bit more, and actually it does happen consistently. > It's just that kmemleak doesn't report it until 10 minutes after > booting, so I did not notice it. > > As for my setup, well, I boot the kernel over pxe and the rootfs is > mounted over NFSv4. The memory leak happens even if I don't do anything > at all - I just boot and wait. The device is a Radxa Rock5B. > > Not sure what other information there is to give. > My question as stated above was mainly to understand if the SCMI stack was built-in or compiled as loadable modules (lsmod|grep -i scmi)... ...I am just to try to pin down a possible 'more-vulnerable' configuration.. ..I could not see any report even triggering a kmemleak scan on v6.14-rc5 BUT I only tested with a fully built-in SCMI stack indeed as of now...so the question. > I tried again with v6.14-rc5, and I still got the leak: Ok...thanks I will investigate with different configs. Thanks, Cristian