From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Tue, 16 Jul 2013 11:36:49 +0100
Subject: [PATCH] arm: align shared memory unconditionally to the SHMLBA
 boundary
In-Reply-To: <51E51EF1.3010104@parallels.com>
References: <1361254269-3444-1-git-send-email-alekskartashov@parallels.com>
 <20130715173238.GJ1730@moon> <20130715180846.GV24642@n2100.arm.linux.org.uk>
 <20130715185739.GK1730@moon> <51E4DC0B.8040908@parallels.com>
 <20130716095349.GB16370@moon> <51E51EF1.3010104@parallels.com>
Message-ID: <20130716103649.GC24642@n2100.arm.linux.org.uk>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Jul 16, 2013 at 02:22:41PM +0400, Alexander Kartashov wrote:
> On 07/16/2013 01:53 PM, Cyrill Gorcunov wrote:
>> Does it mean that we simply can't checkpoint and restore on same
>> node (ie same arm family) if this patch is not applied, right?
> Yes, it does.
>> Is there any possibility to somehow workaround this problem
>> completely in user-space?
> No, it's impossible since an IPC SHM region is allocated
> by the routine shmget() in the dumpee; if the routine
> returns an incorrectly aligned address it's impossible
> to reattach the region at this address while restoring
> the dumpee.

shmget() doesn't allocate space in the process for the SHM region.  It
merely creates the shm memory and returns an identifier for it which can
later be used by shmat() to map it.