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.richard...@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 <ktray...@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 "[]"
