From patchwork Tue Nov 15 22:05:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierre Gondois X-Patchwork-Id: 13044242 X-Patchwork-Delegate: geert@linux-m68k.org 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BCFCC4332F for ; Tue, 15 Nov 2022 22:06:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232010AbiKOWF7 (ORCPT ); Tue, 15 Nov 2022 17:05:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232403AbiKOWF6 (ORCPT ); Tue, 15 Nov 2022 17:05:58 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D3B7F21272; Tue, 15 Nov 2022 14:05:57 -0800 (PST) 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 A0F1913D5; Tue, 15 Nov 2022 14:06:03 -0800 (PST) Received: from pierre123.arm.com (unknown [10.57.6.31]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C04963F73B; Tue, 15 Nov 2022 14:05:54 -0800 (PST) From: Pierre Gondois To: linux-kernel@vger.kernel.org Cc: Rob.Herring@arm.com, sudeep.holla@arm.com, Greg Kroah-Hartman , "Rafael J . Wysocki" , Linux-Renesas , Marek Szyprowski , Geert Uytterhoeven , Pierre Gondois Subject: [PATCH -next] cacheinfo: Remove of_node_put() for fw_token Date: Tue, 15 Nov 2022 23:05:20 +0100 Message-Id: <20221115220520.2076189-1-pierre.gondois@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org fw_token is used for DT/ACPI systems to identify CPUs sharing caches. For DT based systems, fw_token is set to a pointer to a DT node. commit ("cacheinfo: Decrement refcount in cache_setup_of_node()") doesn't increment the refcount of fw_token anymore in cache_setup_of_node(). fw_token is indeed used as a token and not as a (struct device_node*), so no reference to fw_token should be kept. However, [1] is triggered when hotplugging a CPU multiple times since cache_shared_cpu_map_remove() decrements the refcount to fw_token at each CPU unplugging, eventually reaching 0. Remove of_node_put() for fw_token in cache_shared_cpu_map_remove(). [1] [ 53.651182] ------------[ cut here ]------------ [ 53.651186] refcount_t: saturated; leaking memory. [ 53.651223] WARNING: CPU: 4 PID: 32 at lib/refcount.c:22 refcount_warn_saturate (lib/refcount.c:22 (discriminator 3)) [ 53.651241] Modules linked in: [ 53.651249] CPU: 4 PID: 32 Comm: cpuhp/4 Tainted: G W 6.1.0-rc1-14091-g9fdf2ca7b9c8 #76 [ 53.651261] Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Oct 31 2022 [ 53.651268] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 53.651279] pc : refcount_warn_saturate (lib/refcount.c:22 (discriminator 3)) [ 53.651293] lr : refcount_warn_saturate (lib/refcount.c:22 (discriminator 3)) [...] [ 53.651513] Call trace: [...] [ 53.651735] of_node_release (drivers/of/dynamic.c:335) [ 53.651750] kobject_put (lib/kobject.c:677 lib/kobject.c:704 ./include/linux/kref.h:65 lib/kobject.c:721) [ 53.651762] of_node_put (drivers/of/dynamic.c:49) [ 53.651776] free_cache_attributes.part.0 (drivers/base/cacheinfo.c:712) [ 53.651792] cacheinfo_cpu_pre_down (drivers/base/cacheinfo.c:718) [ 53.651807] cpuhp_invoke_callback (kernel/cpu.c:247 (discriminator 4)) [ 53.651819] cpuhp_thread_fun (kernel/cpu.c:785) [ 53.651832] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) [ 53.651847] kthread (kernel/kthread.c:376) [ 53.651858] ret_from_fork (arch/arm64/kernel/entry.S:861) [ 53.651869] ---[ end trace 0000000000000000 ]--- Reported-by: Geert Uytterhoeven Reported-by: Marek Szyprowski Signed-off-by: Pierre Gondois Tested-by: Sudeep Holla Reviewed-by: Sudeep Holla Tested-by: Geert Uytterhoeven --- drivers/base/cacheinfo.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 04317cde800c..950b22cdb5f7 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -317,8 +317,6 @@ static void cache_shared_cpu_map_remove(unsigned int cpu) cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map); cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map); } - if (of_have_populated_dt()) - of_node_put(this_leaf->fw_token); } }