From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: Manfred Schlaegl <manfred.schlaegl@gmx.at>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Manfred Schlaegl <manfred.schlaegl@ginzinger.com>
Subject: Re: [PATCH] video/logo: fix use logo after free prevention
Date: Fri, 17 Apr 2015 10:40:31 +0000 [thread overview]
Message-ID: <5530E31F.2010300@ti.com> (raw)
In-Reply-To: <5530D6D2.8080103@gmx.at>
Hi,
On 04/17/2015 12:48 PM, Manfred Schlaegl wrote:
> After 92b004d1aa9f367c372511ca0330f58216b25703 the logos disappeared on
> Freescale i.MX53 and i.MX6 SoC's (detected on linux-3.12.37).
> This happens because the fb_find_logo function is validly called
> (initdata still not freed) AFTER newly introduced latecall
> fb_logo_late_init.
>
> Instead of stetting a logos_freed flag somewhere in lateinit, this patch
> uses system_state=SYSTEM_BOOTING as indication for valid initdata.
The kernel init does free_initmem() call before setting the system_state
to SYSTEM_RUNNING, so there's a period of time when the logos are freed,
but the check in you patch does not catch it.
Tomi
WARNING: multiple messages have this Message-ID (diff)
From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: Manfred Schlaegl <manfred.schlaegl@gmx.at>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: <linux-fbdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Manfred Schlaegl <manfred.schlaegl@ginzinger.com>
Subject: Re: [PATCH] video/logo: fix use logo after free prevention
Date: Fri, 17 Apr 2015 13:40:31 +0300 [thread overview]
Message-ID: <5530E31F.2010300@ti.com> (raw)
In-Reply-To: <5530D6D2.8080103@gmx.at>
Hi,
On 04/17/2015 12:48 PM, Manfred Schlaegl wrote:
> After 92b004d1aa9f367c372511ca0330f58216b25703 the logos disappeared on
> Freescale i.MX53 and i.MX6 SoC's (detected on linux-3.12.37).
> This happens because the fb_find_logo function is validly called
> (initdata still not freed) AFTER newly introduced latecall
> fb_logo_late_init.
>
> Instead of stetting a logos_freed flag somewhere in lateinit, this patch
> uses system_state==SYSTEM_BOOTING as indication for valid initdata.
The kernel init does free_initmem() call before setting the system_state
to SYSTEM_RUNNING, so there's a period of time when the logos are freed,
but the check in you patch does not catch it.
Tomi
next prev parent reply other threads:[~2015-04-17 10:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-17 9:48 [PATCH] video/logo: fix use logo after free prevention Manfred Schlaegl
2015-04-17 9:48 ` Manfred Schlaegl
2015-04-17 10:40 ` Tomi Valkeinen [this message]
2015-04-17 10:40 ` Tomi Valkeinen
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