linux-kernel - Re: [PATCH] clk: exynos: use irqsave version of spin

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]

Date:	Mon, 14 Dec 2015 20:02:54 +0900
From:	Tomasz Figa <tomasz.figa@...il.com>
To:	Marek Szyprowski <m.szyprowski@...sung.com>
Cc:	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Mike Turquette <mturquette@...libre.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Thomas Abraham <thomas.ab@...sung.com>,
	Ben Gamari <ben@...rt-cactus.org>,
	Lukasz Majewski <l.majewski@...sung.com>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Kevin Hilman <khilman@...aro.org>, stable@...r.kernel.org
Subject: Re: [PATCH] clk: exynos: use irqsave version of spin_lock to avoid
 deadlock with irqs

Hi Marek,

2015-12-11 23:38 GMT+09:00 Marek Szyprowski <m.szyprowski@...sung.com>:
> It is allowed to enable/disable clocks from interrupts, so common Exynos
> ARM clock management code for CPUfreq should use 'irqsave' version of
> spin_lock calls to avoid potential deadlock caused by spin_lock recursion.
> The same spin_lock is used by gate/mux clocks during enable/disable calls.
>
> This deadlock, can be reproduced by enabling CPUfreq (ondemand or
> userspace) and decoding video with s5p-mfc driver.

Good catch.

Acked-by: Tomasz Figa <tomasz.figa@...il.com>

Best regards,
Tomasz
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/