linux-kernel - Re: [PATCH 5.10 051/120] memblock: do not start bottom-up allocations with kernel

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Message-ID: <875z31th2q.fsf@manicouagan.localdomain>
Date:   Tue, 09 Feb 2021 12:07:57 -0300
From:   Thiago Jung Bauermann <bauerman@...ux.ibm.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Roman Gushchin <guro@...com>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Michal Hocko <mhocko@...nel.org>,
        Rik van Riel <riel@...riel.com>,
        Wonhyuk Yang <vvghjk1234@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 5.10 051/120] memblock: do not start bottom-up
 allocations with kernel_end


Greg Kroah-Hartman <gregkh@...uxfoundation.org> writes:

> From: Roman Gushchin <guro@...com>
>
> [ Upstream commit 2dcb3964544177c51853a210b6ad400de78ef17d ]
>
> With kaslr the kernel image is placed at a random place, so starting the
> bottom-up allocation with the kernel_end can result in an allocation
> failure and a warning like this one:

Not sure if this is ready for stable yet (including stable branches 4.19
and 5.4), since it seems to uncover latent bugs in x86 early memory
reservation. I asked about this issue here:

https://lore.kernel.org/lkml/87ft26yuwg.fsf@manicouagan.localdomain/

-- 
Thiago Jung Bauermann
IBM Linux Technology Center