linux-kernel - Re: [PATCH AUTOSEL for 4.14 065/110] led: core: Fix brightness setting when setting delay

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20180204003029.2lkcmh6wvzpnlrls@sasha-lappy>
Date:   Sun, 4 Feb 2018 00:30:36 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     Pavel Machek <pavel@....cz>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Matthieu CASTET <matthieu.castet@...rot.com>,
        "linux-leds@...r.kernel.org" <linux-leds@...r.kernel.org>,
        Jacek Anaszewski <jacek.anaszewski@...il.com>
Subject: Re: [PATCH AUTOSEL for 4.14 065/110] led: core: Fix brightness
 setting when setting delay_off=0

On Sat, Feb 03, 2018 at 09:35:26PM +0100, Pavel Machek wrote:
>On Sat 2018-02-03 18:00:59, Sasha Levin wrote:
>> From: Matthieu CASTET <matthieu.castet@...rot.com>
>>
>> [ Upstream commit 2b83ff96f51d0b039c4561b9f95c824d7bddb85c ]
>>
>> With the current code, the following sequence won't work :
>> echo timer > trigger
>>
>> echo 0 >  delay_off
>> * at this point we call
>> ** led_delay_off_store
>> ** led_blink_set
>> *** stop timer
>> ** led_blink_setup
>> ** led_set_software_blink
>> *** if !delay_on, led off
>> *** if !delay_off, set led_set_brightness_nosleep <--- LED_BLINK_SW is set but timer is stop
>> *** otherwise start timer/set LED_BLINK_SW flag
>>
>> echo xxx > brightness
>> * led_set_brightness
>> ** if LED_BLINK_SW
>> *** if brightness=0, led off
>> *** else apply brightness if next timer <--- timer is stop, and will never apply new setting
>> ** otherwise set led_set_brightness_nosleep
>>
>> To fix that, when we delete the timer, we should clear LED_BLINK_SW.
>
>Can you run the tests on the affected stable kernels? I have feeling
>that the problem described might not be present there.

Hm, I don't seem to have HW to test that out. Maybe someone else does?

-- 

Thanks,
Sasha