From: Bruce Richardson <bruce.richardson@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: dev@dpdk.org, david.marchand@redhat.com, ktraynor@redhat.com,
jingjing.wu@intel.com, beilei.xing@intel.com
Subject: Re: [PATCH 0/4] clean up zero-length arrays
Date: Tue, 14 Jun 2022 10:45:14 +0100 [thread overview]
Message-ID: <YqhYqhG/gENKS1iy@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <YqhXoqNmg+WIc1IY@bricha3-MOBL.ger.corp.intel.com>
On Tue, Jun 14, 2022 at 10:40:50AM +0100, Bruce Richardson wrote:
> On Wed, Jun 08, 2022 at 08:23:02AM -0700, Stephen Hemminger wrote:
> > On Thu, 2 Jun 2022 16:08:30 +0100
> > Bruce Richardson <bruce.richardson@intel.com> wrote:
> >
> > > This patchset adds a coccinelle script to clean-up zero-length
> > > arrays in structures. The final patches are the result of running
> > > that script on the DPDK repository.
> > >
> > > Bruce Richardson (4):
> > > cocci: add script for zero-length arrays in structs
> > > drivers: replace zero-length arrays with undimensioned ones
> > > lib: replace zero-length arrays with undimensioned ones
> > > app: examples: replace zero-length arrays with undimensioned ones
> > >
> > > app/test/test_table_tables.c | 2 +-
> > > devtools/cocci/zero_length_array.cocci | 21 +++++++++++++++
> > > drivers/bus/dpaa/include/netcfg.h | 4 +--
> > > drivers/bus/vmbus/rte_vmbus_reg.h | 4 +--
> > > drivers/common/cnxk/roc_se.h | 2 +-
> > > drivers/common/dpaax/caamflib/desc/ipsec.h | 2 +-
> > > drivers/common/dpaax/dpaax_iova_table.h | 2 +-
> > > drivers/common/mlx5/mlx5_prm.h | 10 +++----
> > > drivers/crypto/ipsec_mb/ipsec_mb_private.h | 4 +--
> > > drivers/crypto/virtio/virtio_ring.h | 4 +--
> > > drivers/crypto/virtio/virtqueue.h | 2 +-
> > > drivers/net/atlantic/hw_atl/hw_atl_utils.h | 2 +-
> > > drivers/net/cxgbe/clip_tbl.h | 2 +-
> > > drivers/net/cxgbe/l2t.h | 2 +-
> > > drivers/net/cxgbe/mps_tcam.h | 2 +-
> > > drivers/net/cxgbe/smt.h | 2 +-
> > > drivers/net/enic/base/vnic_devcmd.h | 2 +-
> > > drivers/net/hinic/hinic_pmd_tx.h | 2 +-
> > > drivers/net/mlx5/mlx5_tx.h | 2 +-
> > > drivers/net/nfp/nfpcore/nfp_nsp.h | 2 +-
> > > drivers/net/virtio/virtio_ring.h | 4 +--
> > > drivers/net/virtio/virtio_user/vhost_kernel.c | 2 +-
> > > drivers/net/virtio/virtio_user/vhost_vdpa.c | 2 +-
> > > drivers/net/virtio/virtqueue.h | 2 +-
> > > drivers/regex/mlx5/mlx5_rxp.h | 4 +--
> > > examples/ip_reassembly/main.c | 2 +-
> > > examples/ptpclient/ptpclient.c | 4 +--
> > > lib/cryptodev/cryptodev_pmd.h | 2 +-
> > > lib/cryptodev/rte_cryptodev.h | 2 +-
> > > lib/eventdev/rte_event_timer_adapter.h | 2 +-
> > > lib/ip_frag/ip_reassembly.h | 2 +-
> > > lib/ipsec/sa.h | 2 +-
> > > lib/rib/rte_rib.c | 2 +-
> > > lib/rib/rte_rib6.c | 2 +-
> > > lib/table/rte_swx_table_learner.c | 4 +--
> > > lib/table/rte_table_hash_key16.c | 4 +--
> > > lib/table/rte_table_hash_key32.c | 4 +--
> > > lib/table/rte_table_hash_key8.c | 4 +--
> > > lib/vhost/rte_vhost.h | 4 +--
> > > 40 files changed, 101 insertions(+), 54 deletions(-)
> > > create mode 100644 devtools/cocci/zero_length_array.cocci
> > > create mode 100644 lib/count_comments.py
> > >
> > > --
> > > 2.34.1
> > >
> >
> > Bruce, looking at this commit, it looks like the underlying cause
> > of the problem with iavf was it is using array size of one
> > when flex array should be used:
> >
> > commit b5b3ea803e4741ad6a46a38d8227c78226d9054d
> > Author: Kevin Traynor <ktraynor@redhat.com>
> > Date: Fri Apr 17 16:43:35 2020 +0100
> >
> > eal/x86: ignore gcc 10 stringop-overflow warnings
> >
> > stringop-overflow warns when it sees a possible overflow
> > in a string operation.
> >
> > In the rte_memcpy functions different branches are taken
> > depending on the size. stringop-overflow is raised for the
> > branches in the function where it sees the static size of the
> > src could be overflowed.
> >
> > However, in reality a correct size argument and in some cases
> > dynamic allocation would ensure that this does not happen.
> >
> > For example, in the case below for key, the correct path will be
> > chosen in rte_memcpy_generic at runtime based on the size argument
> > but as some paths in the function could lead to a cast to 32 bytes
> > a warning is raised.
> >
> > In function ‘_mm256_storeu_si256’,
> > inlined from ‘rte_memcpy_generic’
> > at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:315:2,
> > inlined from ‘iavf_configure_rss_key’
> > at ../lib/librte_eal/common/include/arch/x86/rte_memcpy.h:869:10:
> >
> > /usr/lib/gcc/x86_64-redhat-linux/10/include/avxintrin.h:928:8:
> > warning: writing 32 bytes into a region of size 1 [-Wstringop-overflow=]
> > 928 | *__P = __A;
> > | ~~~~~^~~~~
> > In file included
> > from ../drivers/net/iavf/../../common/iavf/iavf_prototype.h:10,
> > from ../drivers/net/iavf/iavf.h:9,
> > from ../drivers/net/iavf/iavf_vchnl.c:22:
> >
> > ../drivers/net/iavf/iavf_vchnl.c:
> > In function ‘iavf_configure_rss_key’:
> >
> > ../drivers/net/iavf/../../common/iavf/virtchnl.h:508:5:
> > note: at offset 0 to object ‘key’ with size 1 declared here
> > 508 | u8 key[1]; /* RSS hash key, packed bytes */
> > | ^~~
> >
>
> I would tend to agree with your assessment. It looks like the "u8 key[1]"
> value should probably be "u8 key[]", and also in the following structure in
> the file, "u8 lut[1]" should probably be "u8 lut[]".
>
> Adding maintainers for driver on CC
>
> Beilei, Jingjing,
>
> in "common/iavf/virtchnl.h", there are quite a number of values at the end
> of structs which are defined as arrays of size 1. We suspect that many of
> these are placeholder arrays which should be given as unsigned arrays. Is
> this assessment correct?
>
s/unsigned arrays/flexible array members/
i.e. arrays without a given size "[]"
prev parent reply other threads:[~2022-06-14 9:45 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-02 15:08 Bruce Richardson
2022-06-02 15:08 ` [PATCH 1/4] cocci: add script for zero-length arrays in structs Bruce Richardson
2022-06-02 15:08 ` [PATCH 2/4] drivers: replace zero-length arrays with undimensioned ones Bruce Richardson
2022-06-02 15:08 ` [PATCH 3/4] lib: " Bruce Richardson
2022-06-02 15:08 ` [PATCH 4/4] app: examples: " Bruce Richardson
2022-06-02 15:20 ` [PATCH 0/4] clean up zero-length arrays Morten Brørup
2022-06-02 15:35 ` Stephen Hemminger
2022-06-02 16:13 ` [PATCH v2 " Bruce Richardson
2022-06-02 16:13 ` [PATCH v2 1/4] cocci: add script for zero-length arrays in structs Bruce Richardson
2022-06-02 16:13 ` [PATCH v2 2/4] drivers: replace zero-length arrays with undimensioned ones Bruce Richardson
2022-06-03 7:19 ` David Marchand
2022-06-03 7:36 ` Bruce Richardson
2022-06-03 9:18 ` Bruce Richardson
2022-06-02 16:13 ` [PATCH v2 3/4] lib: " Bruce Richardson
2022-06-02 16:13 ` [PATCH v2 4/4] app: examples: " Bruce Richardson
2022-06-03 6:56 ` [PATCH v2 0/4] clean up zero-length arrays Hemant Agrawal
2022-06-03 10:13 ` [PATCH v3 " Bruce Richardson
2022-06-03 10:13 ` [PATCH v3 1/4] cocci: add script for zero-length arrays in structs Bruce Richardson
2022-06-03 10:30 ` Morten Brørup
2022-06-03 10:38 ` Bruce Richardson
2022-06-03 10:13 ` [PATCH v3 2/4] drivers: replace zero-length arrays with undimensioned ones Bruce Richardson
2022-06-03 10:13 ` [PATCH v3 3/4] lib: " Bruce Richardson
2022-06-03 10:13 ` [PATCH v3 4/4] app: examples: " Bruce Richardson
2022-06-03 11:13 ` [PATCH v3 0/4] clean up zero-length arrays Bruce Richardson
2022-06-03 11:16 ` [PATCH v4 " Bruce Richardson
2022-06-03 11:16 ` [PATCH v4 1/4] cocci: add script for zero-length arrays in structs Bruce Richardson
2022-06-03 11:16 ` [PATCH v4 2/4] drivers: replace zero-length arrays with undimensioned ones Bruce Richardson
2022-06-03 11:16 ` [PATCH v4 3/4] lib: " Bruce Richardson
2022-06-03 11:16 ` [PATCH v4 4/4] app: examples: " Bruce Richardson
2022-06-07 14:16 ` [PATCH v4 0/4] clean up zero-length arrays David Marchand
2022-06-09 15:19 ` Tyler Retzlaff
2022-06-08 15:23 ` [PATCH " Stephen Hemminger
2022-06-14 9:40 ` Bruce Richardson
2022-06-14 9:45 ` Bruce Richardson [this message]
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