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 21:14:49 +0100 [thread overview]
Message-ID: <20160430201449.GL2839@codeblueprint.co.uk> (raw)
In-Reply-To: <1461952128-2135409-1-git-send-email-arnd@arndb.de>
On Fri, 29 Apr, at 07:48:31PM, Arnd Bergmann wrote:
> gcc complains about a newly added file for the EFI Bootloader Control:
>
> drivers/firmware/efi/efibc.c: In function 'efibc_set_variable':
> drivers/firmware/efi/efibc.c:53:1: error: the frame size of 2272 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
>
> The problem is the declaration of a local variable of type
> struct efivar_entry, which is by itself larger than the warning
> limit of 1024 bytes.
>
> We know that the reboot notifiers are not called from a deep stack,
> so this is not an actual bug, but we should still try to rework
> the code to avoid the warning. We also know that reboot notifiers
> are never run concurrently on multiple CPUs, so there is no problem
> in just making the variable 'static'.
I assumed reboot notifiers were guaranteed to be non-concurrent too
but having dug into the callers of kernel_reboot(), I couldn't find
any kind of mutual exclusion.
How/where is this guaranteed?
next prev parent reply other threads:[~2016-04-30 20:14 UTC|newest]
Thread overview: 6+ 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 [this message]
[not found] ` <20160430201449.GL2839-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-04-30 22:34 ` Arnd Bergmann
2016-04-30 22:46 ` Matt Fleming
[not found] ` <20160430224641.GQ2839-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-04-30 23:25 ` Arnd Bergmann
2016-05-01 13:13 ` Matt Fleming
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