| Message ID | 20200213010425.GA13068@embeddedor.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Jason Gunthorpe |
| Headers | show |
| Series | IB/core, cache: Replace zero-length array with flexible-array member | expand |
On 2/12/20 19:08, Jason Gunthorpe wrote: > > There are many more of these under core/* care to fix them all in one > patch? > Sure thing. I can do that. Thanks -- Gustavo
On Thu, Feb 13, 2020 at 12:36:39PM -0600, Gustavo A. R. Silva wrote: > > > On 2/12/20 19:08, Jason Gunthorpe wrote: > > > > There are many more of these under core/* care to fix them all in one > > patch? > > > > Sure thing. I can do that. Gustavo, Was checkpatch extended to catch such mistakes? Thanks > > Thanks > -- > Gustavo
On 2/13/20 12:37, Leon Romanovsky wrote: > On Thu, Feb 13, 2020 at 12:36:39PM -0600, Gustavo A. R. Silva wrote: >> >> >> On 2/12/20 19:08, Jason Gunthorpe wrote: >>> >>> There are many more of these under core/* care to fix them all in one >>> patch? >>> >> >> Sure thing. I can do that. > > Gustavo, > > Was checkpatch extended to catch such mistakes? > Not yet. But that's on my list for the short future. Thanks -- Gustavo
On Wed, Feb 12, 2020 at 07:04:25PM -0600, Gustavo A. R. Silva wrote: > The current codebase makes use of the zero-length array language > extension to the C90 standard, but the preferred mechanism to declare > variable-length types such as these ones is a flexible array member[1][2], > introduced in C99: > > struct foo { > int stuff; > struct boo array[]; > }; > > By making use of the mechanism above, we will get a compiler warning > in case the flexible array does not occur last in the structure, which > will help us prevent some kind of undefined behavior bugs from being > inadvertently introduced[3] to the codebase from now on. > > Also, notice that, dynamic memory allocations won't be affected by > this change: > > "Flexible array members have incomplete type, and so the sizeof operator > may not be applied. As a quirk of the original implementation of > zero-length arrays, sizeof evaluates to zero."[1] > > This issue was found with the help of Coccinelle. > > [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html > [2] https://github.com/KSPP/linux/issues/21 > [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > --- > drivers/infiniband/core/cache.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) I squished the four drivers/infiniband patches together and added a few more, see below. Applied to for-next It would be fanatstic to follow this up with some analysis to find cases where sizeof() is performed on a struct with a [] flex array - these days people should be using struct_size() (interested DanC?) Thanks, Jason diff --git a/drivers/infiniband/core/mad_priv.h b/drivers/infiniband/core/mad_priv.h index 956b3a7dfed7ed..403d8673a2f9ea 100644 --- a/drivers/infiniband/core/mad_priv.h +++ b/drivers/infiniband/core/mad_priv.h @@ -79,13 +79,13 @@ struct ib_mad_private { struct ib_mad_private_header header; size_t mad_size; struct ib_grh grh; - u8 mad[0]; + u8 mad[]; } __packed; struct ib_rmpp_segment { struct list_head list; u32 num; - u8 data[0]; + u8 data[]; }; struct ib_mad_agent_private { diff --git a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h index 7d06b0f8d49a00..e8e11bd95e4296 100644 --- a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h +++ b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h @@ -707,7 +707,7 @@ struct mpa_message { u8 flags; u8 revision; __be16 private_data_size; - u8 private_data[0]; + u8 private_data[]; }; struct mpa_v2_conn_params { @@ -719,7 +719,7 @@ struct terminate_message { u8 layer_etype; u8 ecode; __be16 hdrct_rsvd; - u8 len_hdrs[0]; + u8 len_hdrs[]; }; #define TERM_MAX_LENGTH (sizeof(struct terminate_message) + 2 + 18 + 28) diff --git a/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h b/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h index cbdb300a47943a..a2f5e29ef2264d 100644 --- a/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h +++ b/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h @@ -123,7 +123,7 @@ struct fw_ri_dsgl { __be32 len0; __be64 addr0; #ifndef C99_NOT_SUPPORTED - struct fw_ri_dsge_pair sge[0]; + struct fw_ri_dsge_pair sge[]; #endif }; @@ -139,7 +139,7 @@ struct fw_ri_isgl { __be16 nsge; __be32 r2; #ifndef C99_NOT_SUPPORTED - struct fw_ri_sge sge[0]; + struct fw_ri_sge sge[]; #endif }; @@ -149,7 +149,7 @@ struct fw_ri_immd { __be16 r2; __be32 immdlen; #ifndef C99_NOT_SUPPORTED - __u8 data[0]; + __u8 data[]; #endif }; @@ -321,7 +321,7 @@ struct fw_ri_res_wr { __be32 len16_pkd; __u64 cookie; #ifndef C99_NOT_SUPPORTED - struct fw_ri_res res[0]; + struct fw_ri_res res[]; #endif }; diff --git a/drivers/infiniband/hw/hfi1/mad.c b/drivers/infiniband/hw/hfi1/mad.c index a51bcd2b439128..7073f237a94938 100644 --- a/drivers/infiniband/hw/hfi1/mad.c +++ b/drivers/infiniband/hw/hfi1/mad.c @@ -2381,7 +2381,7 @@ struct opa_port_status_rsp { __be64 port_vl_rcv_bubble; __be64 port_vl_mark_fecn; __be64 port_vl_xmit_discards; - } vls[0]; /* real array size defined by # bits set in vl_select_mask */ + } vls[]; /* real array size defined by # bits set in vl_select_mask */ }; enum counter_selects { @@ -2423,7 +2423,7 @@ struct opa_aggregate { __be16 attr_id; __be16 err_reqlength; /* 1 bit, 8 res, 7 bit */ __be32 attr_mod; - u8 data[0]; + u8 data[]; }; #define MSK_LLI 0x000000f0 diff --git a/drivers/infiniband/hw/hfi1/mad.h b/drivers/infiniband/hw/hfi1/mad.h index 2f48e69536290c..889e63d3f2ccd0 100644 --- a/drivers/infiniband/hw/hfi1/mad.h +++ b/drivers/infiniband/hw/hfi1/mad.h @@ -165,7 +165,7 @@ struct opa_mad_notice_attr { } __packed ntc_2048; }; - u8 class_data[0]; + u8 class_data[]; }; #define IB_VLARB_LOWPRI_0_31 1 diff --git a/drivers/infiniband/hw/hfi1/pio.h b/drivers/infiniband/hw/hfi1/pio.h index c9a58b642bdd6f..0102262343c0f6 100644 --- a/drivers/infiniband/hw/hfi1/pio.h +++ b/drivers/infiniband/hw/hfi1/pio.h @@ -243,7 +243,7 @@ struct sc_config_sizes { */ struct pio_map_elem { u32 mask; - struct send_context *ksc[0]; + struct send_context *ksc[]; }; /* @@ -263,7 +263,7 @@ struct pio_vl_map { u32 mask; u8 actual_vls; u8 vls; - struct pio_map_elem *map[0]; + struct pio_map_elem *map[]; }; int pio_map_init(struct hfi1_devdata *dd, u8 port, u8 num_vls, diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c index a51525647ac86b..c93ea021cf4939 100644 --- a/drivers/infiniband/hw/hfi1/sdma.c +++ b/drivers/infiniband/hw/hfi1/sdma.c @@ -833,7 +833,7 @@ struct sdma_engine *sdma_select_engine_sc( struct sdma_rht_map_elem { u32 mask; u8 ctr; - struct sdma_engine *sde[0]; + struct sdma_engine *sde[]; }; struct sdma_rht_node { diff --git a/drivers/infiniband/hw/hfi1/sdma.h b/drivers/infiniband/hw/hfi1/sdma.h index 1e2e40f79cb205..7a851191f9870f 100644 --- a/drivers/infiniband/hw/hfi1/sdma.h +++ b/drivers/infiniband/hw/hfi1/sdma.h @@ -1002,7 +1002,7 @@ void sdma_engine_interrupt(struct sdma_engine *sde, u64 status); */ struct sdma_map_elem { u32 mask; - struct sdma_engine *sde[0]; + struct sdma_engine *sde[]; }; /** @@ -1024,7 +1024,7 @@ struct sdma_vl_map { u32 mask; u8 actual_vls; u8 vls; - struct sdma_map_elem *map[0]; + struct sdma_map_elem *map[]; }; int sdma_map_init( diff --git a/drivers/infiniband/hw/hfi1/user_exp_rcv.h b/drivers/infiniband/hw/hfi1/user_exp_rcv.h index 6257eee083a1a3..332abb446861a9 100644 --- a/drivers/infiniband/hw/hfi1/user_exp_rcv.h +++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.h @@ -73,7 +73,7 @@ struct tid_rb_node { dma_addr_t dma_addr; bool freed; unsigned int npages; - struct page *pages[0]; + struct page *pages[]; }; static inline int num_user_pages(unsigned long addr, diff --git a/drivers/infiniband/hw/i40iw/i40iw_cm.h b/drivers/infiniband/hw/i40iw/i40iw_cm.h index 66dc1ba0338900..6e43e4d730f4c4 100644 --- a/drivers/infiniband/hw/i40iw/i40iw_cm.h +++ b/drivers/infiniband/hw/i40iw/i40iw_cm.h @@ -85,7 +85,7 @@ struct ietf_mpa_v1 { u8 flags; u8 rev; __be16 priv_data_len; - u8 priv_data[0]; + u8 priv_data[]; }; #define ietf_mpa_req_resp_frame ietf_mpa_frame @@ -101,7 +101,7 @@ struct ietf_mpa_v2 { u8 rev; __be16 priv_data_len; struct ietf_rtr_msg rtr_msg; - u8 priv_data[0]; + u8 priv_data[]; }; struct i40iw_cm_node; diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.h b/drivers/infiniband/hw/mthca/mthca_memfree.h index da9b8f9b884f3a..f9a2e65e2ff59a 100644 --- a/drivers/infiniband/hw/mthca/mthca_memfree.h +++ b/drivers/infiniband/hw/mthca/mthca_memfree.h @@ -68,7 +68,7 @@ struct mthca_icm_table { int lowmem; int coherent; struct mutex mutex; - struct mthca_icm *icm[0]; + struct mthca_icm *icm[]; }; struct mthca_icm_iter { diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.h b/drivers/infiniband/hw/usnic/usnic_uiom.h index 70be49b1ca0528..7ec8991ace673e 100644 --- a/drivers/infiniband/hw/usnic/usnic_uiom.h +++ b/drivers/infiniband/hw/usnic/usnic_uiom.h @@ -77,7 +77,7 @@ struct usnic_uiom_reg { struct usnic_uiom_chunk { struct list_head list; int nents; - struct scatterlist page_list[0]; + struct scatterlist page_list[]; }; struct usnic_uiom_pd *usnic_uiom_alloc_pd(void); diff --git a/drivers/infiniband/sw/rxe/rxe_queue.h b/drivers/infiniband/sw/rxe/rxe_queue.h index acd0a925481c95..8ef17d61702214 100644 --- a/drivers/infiniband/sw/rxe/rxe_queue.h +++ b/drivers/infiniband/sw/rxe/rxe_queue.h @@ -63,7 +63,7 @@ struct rxe_queue_buf { __u32 pad_2[31]; __u32 consumer_index; __u32 pad_3[31]; - __u8 data[0]; + __u8 data[]; }; struct rxe_queue { diff --git a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h index 4480092c68e097..0b3570dc606d24 100644 --- a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h +++ b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h @@ -258,7 +258,7 @@ struct opa_veswport_mactable { __be16 offset; __be16 num_entries; __be32 mac_tbl_digest; - struct opa_veswport_mactable_entry tbl_entries[0]; + struct opa_veswport_mactable_entry tbl_entries[]; } __packed; /** @@ -440,7 +440,7 @@ struct opa_veswport_iface_macs { __be16 num_macs_in_msg; __be16 tot_macs_in_lst; __be16 gen_count; - struct opa_vnic_iface_mac_entry entry[0]; + struct opa_vnic_iface_mac_entry entry[]; } __packed; /** diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h index 5359ece561cad8..6fabcc2faf1f08 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.h +++ b/drivers/infiniband/ulp/srp/ib_srp.h @@ -309,7 +309,7 @@ struct srp_fr_pool { int max_page_list_len; spinlock_t lock; struct list_head free_list; - struct srp_fr_desc desc[0]; + struct srp_fr_desc desc[]; }; /** diff --git a/include/rdma/ib_fmr_pool.h b/include/rdma/ib_fmr_pool.h index f8982e4e9702ad..2fd9bfb6d648cc 100644 --- a/include/rdma/ib_fmr_pool.h +++ b/include/rdma/ib_fmr_pool.h @@ -73,7 +73,7 @@ struct ib_pool_fmr { int remap_count; u64 io_virtual_address; int page_list_len; - u64 page_list[0]; + u64 page_list[]; }; struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd *pd, diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 5f3a04ead9f593..bbc5cfb57cd2bb 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -1876,7 +1876,7 @@ struct ib_flow_eth_filter { __be16 ether_type; __be16 vlan_tag; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_eth { @@ -1890,7 +1890,7 @@ struct ib_flow_ib_filter { __be16 dlid; __u8 sl; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_ib { @@ -1915,7 +1915,7 @@ struct ib_flow_ipv4_filter { u8 ttl; u8 flags; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_ipv4 { @@ -1933,7 +1933,7 @@ struct ib_flow_ipv6_filter { u8 traffic_class; u8 hop_limit; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_ipv6 { @@ -1947,7 +1947,7 @@ struct ib_flow_tcp_udp_filter { __be16 dst_port; __be16 src_port; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_tcp_udp { @@ -1959,7 +1959,7 @@ struct ib_flow_spec_tcp_udp { struct ib_flow_tunnel_filter { __be32 tunnel_id; - u8 real_sz[0]; + u8 real_sz[]; }; /* ib_flow_spec_tunnel describes the Vxlan tunnel @@ -1976,7 +1976,7 @@ struct ib_flow_esp_filter { __be32 spi; __be32 seq; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_esp { @@ -1991,7 +1991,7 @@ struct ib_flow_gre_filter { __be16 protocol; __be32 key; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_gre { @@ -2004,7 +2004,7 @@ struct ib_flow_spec_gre { struct ib_flow_mpls_filter { __be32 tag; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_mpls { diff --git a/include/rdma/opa_vnic.h b/include/rdma/opa_vnic.h index 0c07a70bd7f61d..e90b149fe92a0b 100644 --- a/include/rdma/opa_vnic.h +++ b/include/rdma/opa_vnic.h @@ -75,7 +75,7 @@ struct opa_vnic_rdma_netdev { struct rdma_netdev rn; /* keep this first */ /* followed by device private data */ - char *dev_priv[0]; + char *dev_priv[]; }; static inline void *opa_vnic_priv(const struct net_device *dev) diff --git a/include/rdma/rdmavt_mr.h b/include/rdma/rdmavt_mr.h index 72a3856d4057f5..ce6c888f7fe754 100644 --- a/include/rdma/rdmavt_mr.h +++ b/include/rdma/rdmavt_mr.h @@ -85,7 +85,7 @@ struct rvt_mregion { u8 lkey_published; /* in global table */ struct percpu_ref refcount; struct completion comp; /* complete when refcount goes to zero */ - struct rvt_segarray *map[0]; /* the segments */ + struct rvt_segarray *map[]; /* the segments */ }; #define RVT_MAX_LKEY_TABLE_BITS 23 diff --git a/include/rdma/rdmavt_qp.h b/include/rdma/rdmavt_qp.h index 0d5c70e2d8ab33..5fc10108703a43 100644 --- a/include/rdma/rdmavt_qp.h +++ b/include/rdma/rdmavt_qp.h @@ -191,7 +191,7 @@ struct rvt_swqe { u32 ssn; /* send sequence number */ u32 length; /* total length of data in sg_list */ void *priv; /* driver dependent field */ - struct rvt_sge sg_list[0]; + struct rvt_sge sg_list[]; }; /**
On 2/20/20 11:37, Jason Gunthorpe wrote: > > I squished the four drivers/infiniband patches together and added a > few more, see below. Applied to for-next > Great! Thank you. :) > It would be fanatstic to follow this up with some analysis to find > cases where sizeof() is performed on a struct with a [] flex array - > these days people should be using struct_size() (interested DanC?) > I've been working on both things: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/?qt=grep&q=struct_size%28%29+helper Thanks -- Gustavo
diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c index 17bfedd24cc3..dedfbe27916f 100644 --- a/drivers/infiniband/core/cache.c +++ b/drivers/infiniband/core/cache.c @@ -46,7 +46,7 @@ struct ib_pkey_cache { int table_len; - u16 table[0]; + u16 table[]; }; struct ib_update_work {
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/infiniband/core/cache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)