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: <20190923151519.GE2369@hirez.programming.kicks-ass.net>
Date:   Mon, 23 Sep 2019 17:15:19 +0200
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
Subject: Re: [PATCH v6] numa: make node_to_cpumask_map() NUMA_NO_NODE aware

On Tue, Sep 17, 2019 at 08:48:54PM +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://lore.kernel.org/patchwork/patch/1125789/

That is bloody unusable, don't do that. Use:

  https://lkml.kernel.org/r/$MSGID

if anything. Then I can find it in my local mbox without having to
resort to touching a mouse and shitty browser software.

(also patchwork is absolute crap for reading email threads)

Anyway, I found it -- I think, I refused to click the link. I replied
there.

> Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
> Suggested-by: Michal Hocko <mhocko@...nel.org>
> Acked-by: Michal Hocko <mhocko@...e.com>



> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index 4123100e..9859acb 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -861,6 +861,9 @@ void numa_remove_cpu(int cpu)
>   */
>  const struct cpumask *cpumask_of_node(int node)
>  {
> +	if (node == NUMA_NO_NODE)
> +		return cpu_online_mask;

This mandates the caller holds cpus_read_lock() or something, I'm pretty
sure that if I put:

	lockdep_assert_cpus_held();

here, it comes apart real quick. Without holding the cpu hotplug lock,
the online mask is gibberish.

> +
>  	if ((unsigned)node >= nr_node_ids) {
>  		printk(KERN_WARNING
>  			"cpumask_of_node(%d): (unsigned)node >= nr_node_ids(%u)\n",

I still think this makes absolutely no sense what so ever.

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ