From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 859E21E0DBD; Tue, 8 Oct 2024 13:26:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728394001; cv=none; b=M4H2mXv4yvW5z9CJlCoiKSkQ/WEWMwxBdcDhhUx66FwVoFNTmN5p4VNZZzk7n3m/vWsLsUJnqCKZa9nmzQp8+NOe6cRWLXRvbmtxz7iIAm6RSqONu1wk+1ancev7W61uP32M7svHMjuVADVBGj6Zs8ZK7WLJ9bs4/5TamOYAym8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728394001; c=relaxed/simple; bh=/ztHldsEiQZqCncz4eiNOyH/ZCAxpHBKrgNgPl0YsZU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=b7IFgcAwJENo54phkBMSCI9wjfU4MNWrY4ZI1rpeHaGuxMF1knoiCYU2GYqMjSUktTezCROV4drV/wsOgDhWP/LLKZDoD0GCsdjXjeedv44Asd8J53jr35l1pfEGY5hFkKhx9CMzxxGzNH9jx5NhfjefbQEWyvi+C4xfLmIjIUQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kXraJRT7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="kXraJRT7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B922BC4CEC7; Tue, 8 Oct 2024 13:26:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728394001; bh=/ztHldsEiQZqCncz4eiNOyH/ZCAxpHBKrgNgPl0YsZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kXraJRT74M1k/qM8Wg4JhFD0BTsnHCLdz2CjDMegI99m/S2Aj3sqlesqaNW1177Ip wW+y8BszcdtQlxzz/sBky0DBYrweYVwxeT2+GoVDHXppApl75qbguJIDt+64ABcSFb jdhoOsq9TBT0eJlyn4IscoC/rZtOO4kRgOtW1JN4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mathieu Desnoyers , Wei Li , "Steven Rostedt (Google)" Subject: [PATCH 6.6 317/386] tracing/hwlat: Fix a race during cpuhp processing Date: Tue, 8 Oct 2024 14:09:22 +0200 Message-ID: <20241008115641.860394410@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241008115629.309157387@linuxfoundation.org> References: <20241008115629.309157387@linuxfoundation.org> User-Agent: quilt/0.67 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wei Li commit 2a13ca2e8abb12ee43ada8a107dadca83f140937 upstream. The cpuhp online/offline processing race also exists in percpu-mode hwlat tracer in theory, apply the fix too. That is: T1 | T2 [CPUHP_ONLINE] | cpu_device_down() hwlat_hotplug_workfn() | | cpus_write_lock() | takedown_cpu(1) | cpus_write_unlock() [CPUHP_OFFLINE] | cpus_read_lock() | start_kthread(1) | cpus_read_unlock() | Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20240924094515.3561410-5-liwei391@huawei.com Fixes: ba998f7d9531 ("trace/hwlat: Support hotplug operations") Signed-off-by: Wei Li Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_hwlat.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -520,6 +520,8 @@ static void hwlat_hotplug_workfn(struct if (!hwlat_busy || hwlat_data.thread_mode != MODE_PER_CPU) goto out_unlock; + if (!cpu_online(cpu)) + goto out_unlock; if (!cpumask_test_cpu(cpu, tr->tracing_cpumask)) goto out_unlock;