mbox series

[0/4] clean up zero-length arrays

Message ID 20220602150834.643745-1-bruce.richardson@intel.com (mailing list archive)
Headers
Series clean up zero-length arrays |

Message

Bruce Richardson June 2, 2022, 3:08 p.m. UTC
  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
  

Comments

Morten Brørup June 2, 2022, 3:20 p.m. UTC | #1
> From: Bruce Richardson [mailto:bruce.richardson@intel.com]
> Sent: Thursday, 2 June 2022 17.09
> 
> 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
> 

Series-Acked-by: Morten Brørup <mb@smartsharesystems.com>
  
Stephen Hemminger June 2, 2022, 3:35 p.m. UTC | #2
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
> 

Series-acked-by: Stephen Hemminger <stephen@networkplumber.org>

Would it be possible to add check for zero length arrays in checkpatch?
So that new drivers don't bring the problem back.
  
Stephen Hemminger June 8, 2022, 3:23 p.m. UTC | #3
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 */
          |     ^~~
    
    Ignore the stringop-overflow warnings for rte_memcpy.h functions.
    
    Bugzilla ID: 394
    Bugzilla ID: 421
    Cc: stable@dpdk.org
    
    Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
    Acked-by: Bruce Richardson <bruce.richardson@intel.com>
    Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
  
Bruce Richardson June 14, 2022, 9:40 a.m. UTC | #4
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?

/Bruce
  
Bruce Richardson June 14, 2022, 9:45 a.m. UTC | #5
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 "[]"