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Message-ID: <CAGXu5jKhYP=5YNuntzmG64WL92F59VKhByOh9nqaGP7-LBEnng@mail.gmail.com>
Date: Thu, 12 Jan 2017 09:26:09 -0800
From: Kees Cook <keescook@...omium.org>
To: Michal Hocko <mhocko@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Vlastimil Babka <vbabka@...e.cz>,
David Rientjes <rientjes@...gle.com>,
Mel Gorman <mgorman@...e.de>,
Johannes Weiner <hannes@...xchg.org>,
Al Viro <viro@...iv.linux.org.uk>,
Linux-MM <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>,
Michal Hocko <mhocko@...e.com>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Tony Luck <tony.luck@...el.com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Ben Skeggs <bskeggs@...hat.com>,
Kent Overstreet <kent.overstreet@...il.com>,
Santosh Raspatur <santosh@...lsio.com>,
Hariprasad S <hariprasad@...lsio.com>,
Tariq Toukan <tariqt@...lanox.com>,
Yishai Hadas <yishaih@...lanox.com>,
Dan Williams <dan.j.williams@...el.com>,
Oleg Drokin <oleg.drokin@...el.com>,
Andreas Dilger <andreas.dilger@...el.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
David Sterba <dsterba@...e.com>,
"Yan, Zheng" <zyan@...hat.com>, Ilya Dryomov <idryomov@...il.com>,
Alexei Starovoitov <ast@...nel.org>,
Eric Dumazet <eric.dumazet@...il.com>,
Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants
On Thu, Jan 12, 2017 at 7:37 AM, Michal Hocko <mhocko@...nel.org> wrote:
> From: Michal Hocko <mhocko@...e.com>
>
> There are many code paths opencoding kvmalloc. Let's use the helper
> instead. The main difference to kvmalloc is that those users are usually
> not considering all the aspects of the memory allocator. E.g. allocation
> requests < 64kB are basically never failing and invoke OOM killer to
> satisfy the allocation. This sounds too disruptive for something that
> has a reasonable fallback - the vmalloc. On the other hand those
> requests might fallback to vmalloc even when the memory allocator would
> succeed after several more reclaim/compaction attempts previously. There
> is no guarantee something like that happens though.
>
> This patch converts many of those places to kv[mz]alloc* helpers because
> they are more conservative.
>
> Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
> Cc: Heiko Carstens <heiko.carstens@...ibm.com>
> Cc: Herbert Xu <herbert@...dor.apana.org.au>
> Cc: Anton Vorontsov <anton@...msg.org>
> Cc: Colin Cross <ccross@...roid.com>
> Cc: Kees Cook <keescook@...omium.org>
> Cc: Tony Luck <tony.luck@...el.com>
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Ben Skeggs <bskeggs@...hat.com>
> Cc: Kent Overstreet <kent.overstreet@...il.com>
> Cc: Santosh Raspatur <santosh@...lsio.com>
> Cc: Hariprasad S <hariprasad@...lsio.com>
> Cc: Tariq Toukan <tariqt@...lanox.com>
> Cc: Yishai Hadas <yishaih@...lanox.com>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Oleg Drokin <oleg.drokin@...el.com>
> Cc: Andreas Dilger <andreas.dilger@...el.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
> Cc: David Sterba <dsterba@...e.com>
> Cc: "Yan, Zheng" <zyan@...hat.com>
> Cc: Ilya Dryomov <idryomov@...il.com>
> Cc: Alexander Viro <viro@...iv.linux.org.uk>
> Cc: Alexei Starovoitov <ast@...nel.org>
> Cc: Eric Dumazet <eric.dumazet@...il.com>
> Cc: netdev@...r.kernel.org
> Signed-off-by: Michal Hocko <mhocko@...e.com>
> ---
> arch/s390/kvm/kvm-s390.c | 10 ++-----
> crypto/lzo.c | 4 +--
> drivers/acpi/apei/erst.c | 8 ++---
> drivers/char/agp/generic.c | 8 +----
> drivers/gpu/drm/nouveau/nouveau_gem.c | 4 +--
> drivers/md/bcache/util.h | 12 ++------
> drivers/net/ethernet/chelsio/cxgb3/cxgb3_defs.h | 3 --
> drivers/net/ethernet/chelsio/cxgb3/cxgb3_offload.c | 25 ++--------------
> drivers/net/ethernet/chelsio/cxgb3/l2t.c | 2 +-
> drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c | 31 ++++----------------
> drivers/net/ethernet/mellanox/mlx4/en_tx.c | 9 ++----
> drivers/net/ethernet/mellanox/mlx4/mr.c | 9 ++----
> drivers/nvdimm/dimm_devs.c | 5 +---
> .../staging/lustre/lnet/libcfs/linux/linux-mem.c | 11 +------
> drivers/xen/evtchn.c | 14 +--------
> fs/btrfs/ctree.c | 9 ++----
> fs/btrfs/ioctl.c | 9 ++----
> fs/btrfs/send.c | 27 ++++++-----------
> fs/ceph/file.c | 9 ++----
> fs/select.c | 5 +---
> fs/xattr.c | 27 ++++++-----------
> kernel/bpf/hashtab.c | 11 ++-----
> lib/iov_iter.c | 5 +---
> mm/frame_vector.c | 5 +---
> net/ipv4/inet_hashtables.c | 6 +---
> net/ipv4/tcp_metrics.c | 5 +---
> net/mpls/af_mpls.c | 5 +---
> net/netfilter/x_tables.c | 34 ++++++----------------
> net/netfilter/xt_recent.c | 5 +---
> net/sched/sch_choke.c | 5 +---
> net/sched/sch_fq_codel.c | 26 ++++-------------
> net/sched/sch_hhf.c | 33 ++++++---------------
> net/sched/sch_netem.c | 6 +---
> net/sched/sch_sfq.c | 6 +---
> security/keys/keyctl.c | 22 ++++----------
> 35 files changed, 96 insertions(+), 319 deletions(-)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 4f74511015b8..e6bbb33d2956 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -1126,10 +1126,7 @@ static long kvm_s390_get_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
> if (args->count < 1 || args->count > KVM_S390_SKEYS_MAX)
> return -EINVAL;
>
> - keys = kmalloc_array(args->count, sizeof(uint8_t),
> - GFP_KERNEL | __GFP_NOWARN);
> - if (!keys)
> - keys = vmalloc(sizeof(uint8_t) * args->count);
> + keys = kvmalloc(args->count * sizeof(uint8_t), GFP_KERNEL);
Before doing this conversion, can we add a kvmalloc_array() API? This
conversion could allow for the reintroduction of integer overflow
flaws. (This particular situation isn't at risk since ->count is
checked, but I'd prefer we not create a risky set of examples for
using kvmalloc.)
Besides that: yes please. Less open coding. :)
-Kees
--
Kees Cook
Nexus Security
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