From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
To: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
Cc: "Compostella,
Jeremy"
<jeremy.compostella-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] efibc: avoid stack overflow warning
Date: Sat, 30 Apr 2016 23:46:41 +0100 [thread overview]
Message-ID: <20160430224641.GQ2839@codeblueprint.co.uk> (raw)
In-Reply-To: <18565207.dPI1UNgYiO@wuerfel>
On Sun, 01 May, at 12:34:29AM, Arnd Bergmann wrote:
>
> The sys_restart() system call takes a mutex before calling kernel_restart()
> or kernel_poweroff().
>
> I've had a closer look now and found that there are a few other
> callers of kernel_restart, so I guess if you restart using sysctl
> at the exact same time as calling /sbin/reboot, things may break.
Right. Or if the dm-verify-target driver saw an error.
> It's not something we'd have to worry about in practice, but it does
> make my patch incorrect. Should we come up with a different way to
> do it?
Jeremy proposed a patch to dynamically allocate the memory, which I
think is the correct way to go given that our (reasonable) assumptions
about reboot notifier concurrency are not guaranteed,
https://lkml.kernel.org/r/87h9eked24.fsf-e2kLcBBGnpIIbNWpFUBdLQzuBQEzu/OPQQ4Iyu8u01E@public.gmane.org
WARNING: multiple messages have this Message-ID (diff)
From: Matt Fleming <matt@codeblueprint.co.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Compostella, Jeremy" <jeremy.compostella@intel.com>,
Ingo Molnar <mingo@kernel.org>,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] efibc: avoid stack overflow warning
Date: Sat, 30 Apr 2016 23:46:41 +0100 [thread overview]
Message-ID: <20160430224641.GQ2839@codeblueprint.co.uk> (raw)
In-Reply-To: <18565207.dPI1UNgYiO@wuerfel>
On Sun, 01 May, at 12:34:29AM, Arnd Bergmann wrote:
>
> The sys_restart() system call takes a mutex before calling kernel_restart()
> or kernel_poweroff().
>
> I've had a closer look now and found that there are a few other
> callers of kernel_restart, so I guess if you restart using sysctl
> at the exact same time as calling /sbin/reboot, things may break.
Right. Or if the dm-verify-target driver saw an error.
> It's not something we'd have to worry about in practice, but it does
> make my patch incorrect. Should we come up with a different way to
> do it?
Jeremy proposed a patch to dynamically allocate the memory, which I
think is the correct way to go given that our (reasonable) assumptions
about reboot notifier concurrency are not guaranteed,
https://lkml.kernel.org/r/87h9eked24.fsf@jcompost-MOBL1.tl.intel.com
next prev parent reply other threads:[~2016-04-30 22:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-29 17:48 [PATCH] efibc: avoid stack overflow warning Arnd Bergmann
2016-04-30 20:14 ` Matt Fleming
[not found] ` <20160430201449.GL2839-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-04-30 22:34 ` Arnd Bergmann
2016-04-30 22:34 ` Arnd Bergmann
2016-04-30 22:46 ` Matt Fleming [this message]
2016-04-30 22:46 ` Matt Fleming
[not found] ` <20160430224641.GQ2839-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-04-30 23:25 ` Arnd Bergmann
2016-04-30 23:25 ` Arnd Bergmann
2016-05-01 13:13 ` Matt Fleming
2016-05-01 13:13 ` Matt Fleming
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