From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Christopher Lameter <cl@linux.com>,
Kees Cook <keescook@chromium.org>, Jiri Slaby <jslaby@suse.cz>,
Julian Wiedmann <jwi@linux.ibm.com>,
Ursula Braun <ubraun@linux.ibm.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-kernel@vger.kernel.org, David Windsor <dave@nullcore.net>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-xfs@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Laura Abbott <labbott@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Christoffer Dall <christoffer.dall@linaro.org>,
Dave Kleikamp <dave.kleikamp@oracle.com>, Jan Kara <jack@suse.cz>,
Luis de Bethencourt <luisbg@kernel.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Rik van Riel <riel@redhat.com>,
Matthew Garrett <mjg59@google.com>,
linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org,
netdev@vger.kernel.org, kernel-hardening@lists.openwall.com,
Vlastimil Babka <vbabka@suse.cz>,
Michal Kubecek <mkubecek@suse.cz>
Subject: Re: [kernel-hardening] [PATCH 09/38] usercopy: Mark kmalloc caches as usercopy caches
Date: Wed, 29 Jan 2020 18:19:56 +0100 [thread overview]
Message-ID: <771c5511-c5ab-3dd1-d938-5dbc40396daa@de.ibm.com> (raw)
In-Reply-To: <20200129170939.GA4277@infradead.org>
On 29.01.20 18:09, Christoph Hellwig wrote:
> On Wed, Jan 29, 2020 at 06:07:14PM +0100, Christian Borntraeger wrote:
>>> DMA can be done to NORMAL memory as well.
>>
>> Exactly.
>> I think iucv uses GFP_DMA because z/VM needs those buffers to reside below 2GB (which is ZONA_DMA for s390).
>
> The normal way to allocate memory with addressing limits would be to
> use dma_alloc_coherent and friends. Any chance to switch iucv over to
> that? Or is there no device associated with it?
There is not necessarily a device for that. It is a hypervisor interface (an
instruction that is interpreted by z/VM). We do have the netiucv driver that
creates a virtual nic, but there is also AF_IUCV which works without a device.
But back to the original question: If we mark kmalloc caches as usercopy caches,
we should do the same for DMA kmalloc caches. As outlined by Christoph, this has
nothing to do with device DMA.
next prev parent reply other threads:[~2020-01-29 17:20 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1515636190-24061-1-git-send-email-keescook@chromium.org>
2018-01-11 2:02 ` [PATCH 06/38] usercopy: Prepare for usercopy whitelisting Kees Cook
2018-01-11 2:02 ` [PATCH 07/38] usercopy: WARN() on slab cache usercopy region violations Kees Cook
2018-01-11 2:02 ` [PATCH 09/38] usercopy: Mark kmalloc caches as usercopy caches Kees Cook
2019-11-12 7:17 ` [kernel-hardening] " Jiri Slaby
2019-11-12 21:21 ` Kees Cook
2019-11-14 21:27 ` Kees Cook
2020-01-23 8:14 ` Jiri Slaby
2020-01-27 23:19 ` Kees Cook
2020-01-28 7:58 ` Christian Borntraeger
2020-01-28 23:01 ` Kees Cook
2020-01-29 9:26 ` Ursula Braun
2020-01-29 16:43 ` Christopher Lameter
2020-01-29 17:07 ` Christian Borntraeger
2020-01-29 17:09 ` Christoph Hellwig
2020-01-29 17:19 ` Christian Borntraeger [this message]
2020-01-30 19:23 ` Kees Cook
2020-01-31 12:03 ` Jann Horn
2020-02-01 17:56 ` Kees Cook
2020-02-01 19:27 ` Jann Horn
2020-02-03 7:46 ` Matthew Wilcox
2020-02-03 17:41 ` Christoph Hellwig
2020-02-03 17:20 ` Christopher Lameter
2020-04-07 8:00 ` Vlastimil Babka
2020-04-07 11:05 ` Christian Borntraeger
2020-04-20 7:53 ` Jiri Slaby
2020-04-20 17:43 ` Kees Cook
2020-02-03 17:38 ` Christoph Hellwig
2020-02-03 17:36 ` Christoph Hellwig
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