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 1918D4BA1F4; Thu, 17 Sep 2026 15:50:21 +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=1789660226; cv=none; b=YPGWbN02+HM1BPEAls51nBcxiEZB8MznehrVTIyg8Lc/4qgYxe91GonzWJkEhJbDx6o5BQt0hEIvY9JjW2YwoKcNj58XltJXMRmW8d/jx0oga/T2QffHRTBMHhX6DrqoxDmoZBUYs8rt5uFBehnqvpHRlq3mC9UpcUi1RfQSTdM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660226; c=relaxed/simple; bh=L39cWHvuk5Uis3xl+WT0dqvETjV7vYnLFZjYvIOCh9s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ly4JVLhRe8Oo3VlHnETUJM/jHL8W0yfB/bhoFjz6BM/du5QHw4Ryz60Ejjl8QzTmCyrOVTahq6v3WRcIWaXZbYZy/4R9lM4OnMUg5VyPi/Ya6u/Wotr9FyQX1AuRfZDGmA8KgPG/zg4A5aTtLbtbdJ8nAdTNsJMTzx98ojKwZMA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=k+onUllE; 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="k+onUllE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 662131F00893; Thu, 17 Sep 2026 15:50:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789660220; bh=gJBtWSv9WDQDez0UNKcF/1ruxmWhxLcZcFyhoB5cb6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=k+onUllEeDIBwxIuuFA4XqoDaHlws4hFc7Qz55pMtluaCT9jA5y4NAXcubY7Bq14f ka4gQXEgGOemVatwh+Ie/svJtnfd5TeodzC0tbLWTZ38ngkmfLro6QSIHttV2qaYkp WjWQESWClVq9m3xaLQ/VFN0OZH2ujoz7GXEPA3z8= 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 7.2 519/733] cpufreq: zero-initialize policy cpumask before sysfs publication Date: Thu, 17 Sep 2026 16:13:47 +0100 Message-ID: <20260917151405.089889603@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@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 7.2-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 @@ -1249,7 +1249,7 @@ 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))