linux-kernel - Re: [PATCH AUTOSEL for 4.15 104/124] clk: fix reentrancy of clk

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: <20180319165818.7bxduuoaeptjsvoh@sasha-lappy>
Date:   Mon, 19 Mar 2018 16:58:20 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     David Lechner <david@...hnology.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Stephen Boyd <sboyd@...eaurora.org>
Subject: Re: [PATCH AUTOSEL for 4.15 104/124] clk: fix reentrancy of
 clk_enable() on UP systems

On Mon, Mar 19, 2018 at 10:55:16AM -0500, David Lechner wrote:
>On 03/19/2018 10:48 AM, Sasha Levin wrote:
>>From: David Lechner <david@...hnology.com>
>>
>>[ Upstream commit a12aa8a68dfef5de181f2e555aa950a0ab05411f ]
>>
>>Reentrant calls to clk_enable() are not working on UP systems. This is
>>caused by the fact spin_trylock_irqsave() always returns true when
>>CONFIG_SMP=n (and CONFIG_DEBUG_SPINLOCK=n) which causes the reference
>>counting to not work correctly when clk_enable_lock() is called twice
>>before clk_enable_unlock() is called (this happens when clk_enable()
>>is called from within another clk_enable()).
>>
>>This fixes the problem by skipping the call to spin_trylock_irqsave() on UP
>>systems and relying solely on reference counting. We also make sure to set
>>flags in this case so that we are not returning an uninitialized value.
>>
>>Suggested-by: Stephen Boyd <sboyd@...eaurora.org>
>>Signed-off-by: David Lechner <david@...hnology.com>
>>Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
>>Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
>>---
>
>I don't know of any existing bugs in v4.15 that this fixes, so I don't
>think this really fits the criteria for stable.
>

I'll remove it, thanks David!

-- 

Thanks,
Sasha