linux-kernel - Re: [PATCH v7] numa: make node_to_cpumask_map() NUMA_NO

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:   Wed, 30 Oct 2019 11:14:49 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Yunsheng Lin <linyunsheng@...wei.com>
Cc:     catalin.marinas@....com, will@...nel.org, mingo@...hat.com,
        bp@...en8.de, rth@...ddle.net, ink@...assic.park.msu.ru,
        mattst88@...il.com, benh@...nel.crashing.org, paulus@...ba.org,
        mpe@...erman.id.au, heiko.carstens@...ibm.com, gor@...ux.ibm.com,
        borntraeger@...ibm.com, ysato@...rs.sourceforge.jp,
        dalias@...c.org, davem@...emloft.net, ralf@...ux-mips.org,
        paul.burton@...s.com, jhogan@...nel.org, jiaxun.yang@...goat.com,
        chenhc@...ote.com, akpm@...ux-foundation.org, rppt@...ux.ibm.com,
        anshuman.khandual@....com, tglx@...utronix.de, cai@....pw,
        robin.murphy@....com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, hpa@...or.com, x86@...nel.org,
        dave.hansen@...ux.intel.com, luto@...nel.org, len.brown@...el.com,
        axboe@...nel.dk, dledford@...hat.com, jeffrey.t.kirsher@...el.com,
        linux-alpha@...r.kernel.org, naveen.n.rao@...ux.vnet.ibm.com,
        mwb@...ux.vnet.ibm.com, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
        sparclinux@...r.kernel.org, tbogendoerfer@...e.de,
        linux-mips@...r.kernel.org, rafael@...nel.org, mhocko@...nel.org,
        gregkh@...uxfoundation.org, bhelgaas@...gle.com,
        linux-pci@...r.kernel.org, rjw@...ysocki.net, lenb@...nel.org,
        linux-acpi@...r.kernel.org
Subject: Re: [PATCH v7] numa: make node_to_cpumask_map() NUMA_NO_NODE aware

On Wed, Oct 30, 2019 at 05:34:28PM +0800, Yunsheng Lin wrote:
> When passing the return value of dev_to_node() to cpumask_of_node()
> without checking if the device's node id is NUMA_NO_NODE, there is
> global-out-of-bounds detected by KASAN.
> 
> From the discussion [1], NUMA_NO_NODE really means no node affinity,
> which also means all cpus should be usable. So the cpumask_of_node()
> should always return all cpus online when user passes the node id as
> NUMA_NO_NODE, just like similar semantic that page allocator handles
> NUMA_NO_NODE.
> 
> But we cannot really copy the page allocator logic. Simply because the
> page allocator doesn't enforce the near node affinity. It just picks it
> up as a preferred node but then it is free to fallback to any other numa
> node. This is not the case here and node_to_cpumask_map will only restrict
> to the particular node's cpus which would have really non deterministic
> behavior depending on where the code is executed. So in fact we really
> want to return cpu_online_mask for NUMA_NO_NODE.
> 
> Also there is a debugging version of node_to_cpumask_map() for x86 and
> arm64, which is only used when CONFIG_DEBUG_PER_CPU_MAPS is defined, this
> patch changes it to handle NUMA_NO_NODE as normal node_to_cpumask_map().
> 
> [1] https://lkml.org/lkml/2019/9/11/66
> Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
> Suggested-by: Michal Hocko <mhocko@...nel.org>
> Acked-by: Michal Hocko <mhocko@...e.com>
> Acked-by: Paul Burton <paul.burton@...s.com> # MIPS bits

Still:

Nacked-by: Peter Zijlstra (Intel) <peterz@...radead.org>