linux-kernel - RE: [PATCH v3] PM / devfreq: Fix devfreq_add_device() when drivers are built as modules.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180703105723epcms1p63bd7b3cf49722b204d7ca0dfd98d5d15@epcms1p6>
Date:   Tue, 03 Jul 2018 19:57:23 +0900
From:   MyungJoo Ham <myungjoo.ham@...sung.com>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "kernel@...labora.com" <kernel@...labora.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: RE: [PATCH v3] PM / devfreq: Fix devfreq_add_device() when drivers
 are built as modules.

>@@ -988,12 +1030,13 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
> 	if (ret != 1)
> 		return -EINVAL;
> 
>-	mutex_lock(&devfreq_list_lock);
>-	governor = find_devfreq_governor(str_governor);
>+	governor = try_then_request_governor(str_governor);
> 	if (IS_ERR(governor)) {
>-		ret = PTR_ERR(governor);
>-		goto out;
>+		return PTR_ERR(governor);
> 	}
>+
>+	mutex_lock(&devfreq_list_lock);
>+
> 	if (df->governor == governor) {
> 		ret = 0;
> 		goto out;
>-- 

The possibility that the result of try_then_request_governor is
not kept protected until the line of
"if (df->governor == governor)" is itching.

Can you make it kept "locked" from the return of
find_devfreq_governor() (either in try_then... or in this function)
to the unlock of governor_store()?


Cheers,
MyungJoo