From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9021738E8CE; Wed, 30 Sep 2026 18:07:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791662; cv=none; b=eG+vf3EsgQ2+TkckGO4BbSHoMzDXQ2mE0IQJpELIhU5Fy4rjOU1CZZUeOnBqCYUsn+mmOneL4/vWufa+Xw4rZciwDUPLmAP1P/LRjzctW9DYh0yr+c16Z0dcKH9Ws0ZnsbcCtJOYmwNVn5xsEhUe0ElZQ8nGq1S0+4ihLPEWlDo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791662; c=relaxed/simple; bh=jRG8VDHh5z3624InEz/zwHuQVopBpvEiUat5ploZ18E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QLsR0oenPYNVG42OFfEyFwbMk7vQqSa10VF6nimlYWmVbOnXqVV7n+38TaveklXNXUTBgy/IcxzblGhPwDOgvIAZZC9JvXmHkxAUY97hthNFjEClvHklio/pmkg9Avb7cHa+Sh6nbRlimZuWBApJhtn+Sh5AnSmucZu5gQftra8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RN/UsiCM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RN/UsiCM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E50051F000FF; Wed, 30 Sep 2026 18:07:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791661; bh=d4Nn+Jel0REkY9d7F6u2o9HY+5FpyaFRl9e3OgiU320=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RN/UsiCMHwtsRxqYKK1VnxwxEeTZSrW/mHxhyI/eve432dSEdrP2aGIC9AGOCDYiI znQv7GwpYn7EOzVA6QUIUfFZBkESgf/huDMxUDXakr9cEKjGC7ElpO4ltVmGe24XAu gZu17D1Xxsdq0+NxrQ6OlpniSnN9SFGEs/EYlBYc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhongqiu Han , Viresh Kumar , "Rafael J. Wysocki" Subject: [PATCH 5.15 382/752] cpufreq: zero-initialize policy cpumask before sysfs publication Date: Wed, 30 Sep 2026 17:24:12 +0200 Message-ID: <20260930152406.541693655@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhongqiu Han commit 54d37bcf2f497140b9207968557ddb484058e749 upstream. cpufreq_policy_alloc() allocates policy->cpus with alloc_cpumask_var(), i.e. without __GFP_ZERO, unlike the sibling related_cpus and real_cpus masks. With CONFIG_CPUMASK_OFFSTACK=y the mask is a separate kmalloc_node() allocation, so its bitmap holds whatever the slab allocator left behind: cpufreq_online() cpufreq_policy_alloc() alloc_cpumask_var(&policy->cpus) /* bitmap is uninitialized */ kobject_init_and_add() /* policy%u/ appears in sysfs */ cpufreq_policy_online() cpumask_copy(policy->cpus, cpumask_of(cpu)) /* first valid value */ This leaves a window in which the sysfs attributes are already reachable while policy->cpus is still garbage. show()/store() gate on policy_is_inactive(), i.e. cpumask_empty(policy->cpus), so a non-zero bitmap makes them run the attribute callbacks on a policy that is not initialized yet. Fix this by using zalloc_cpumask_var() for policy->cpus. Fixes: 2fc3384dc75b ("cpufreq: Initialize policy->kobj while allocating policy") Cc: All applicable Signed-off-by: Zhongqiu Han Acked-by: Viresh Kumar Link: https://patch.msgid.link/20260901143635.4106960-1-zhongqiu.han@oss.qualcomm.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1205,7 +1205,7 @@ static struct cpufreq_policy *cpufreq_po if (!policy) return NULL; - if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) + if (!zalloc_cpumask_var(&policy->cpus, GFP_KERNEL)) goto err_free_policy; if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))