linux-kernel - Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with kernel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210124073421.GG6332@kernel.org>
Date:   Sun, 24 Jan 2021 09:34:21 +0200
From:   Mike Rapoport <rppt@...nel.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Thiago Jung Bauermann <bauerman@...ux.ibm.com>, guro@...com,
        iamjoonsoo.kim@....com, Ram Pai <linuxram@...ibm.com>,
        Konrad Rzeszutek Wilk <konrad@...nok.org>,
        Satheesh Rajendran <sathnaga@...ux.vnet.ibm.com>,
        kernel-team@...com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linuxppc-dev@...ts.ozlabs.org,
        mhocko@...nel.org, riel@...riel.com
Subject: Re: [PATCH v2 2/2] memblock: do not start bottom-up allocations with
 kernel_end

On Sat, Jan 23, 2021 at 06:09:11PM -0800, Andrew Morton wrote:
> On Fri, 22 Jan 2021 01:37:14 -0300 Thiago Jung Bauermann <bauerman@...ux.ibm.com> wrote:
> 
> > Mike Rapoport <rppt@...nel.org> writes:
> > 
> > > > Signed-off-by: Roman Gushchin <guro@...com>
> > > 
> > > Reviewed-by: Mike Rapoport <rppt@...ux.ibm.com>
> > 
> > I've seen a couple of spurious triggers of the WARN_ONCE() removed by this
> > patch. This happens on some ppc64le bare metal (powernv) server machines with
> > CONFIG_SWIOTLB=y and crashkernel=4G, as described in a candidate patch I posted
> > to solve this issue in a different way:
> > 
> > https://lore.kernel.org/linuxppc-dev/20201218062103.76102-1-bauerman@linux.ibm.com/
> > 
> > Since this patch solves that problem, is it possible to include it in the next
> > feasible v5.11-rcX, with the following tag?
> 
> We could do this, if we're confident that this patch doesn't depend on
> [1/2] "mm: cma: allocate cma areas bottom-up"?  I think it is...

A think it does not depend on cma bottom-up allocation, it's rather the other
way around: without this CMA bottom-up allocation could fail with KASLR
enabled.

Still, this patch may need updates to the way x86 does early reservations:

https://lore.kernel.org/lkml/20210115083255.12744-1-rppt@kernel.org
 
> > Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory")
> 
> I added that.
> 
> 

-- 
Sincerely yours,
Mike.