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>
Signed-off-by: David S. Miller <davem@davemloft.net>
uint32_t addr;
uint32_t len;
uint32_t version;
- uint8_t buf[0];
+ uint8_t buf[];
};
struct ch_qset_params {
#endif
__be32 msn;
__be32 mo;
- __u8 data[0];
+ __u8 data[];
};
/* cpl_rdma_terminate.tid_len fields */
atomic_t nfree;
struct list_head ce_free_head;
void *cl_list;
- struct list_head hash_list[0];
+ struct list_head hash_list[];
};
enum {
struct cudbg_tp_la {
u32 size;
u32 mode;
- u8 data[0];
+ u8 data[];
};
static const char * const cudbg_region[] = {
struct cudbg_cim_pif_la {
int size;
- u8 data[0];
+ u8 data[];
};
struct cudbg_clk_info {
u32 qid;
u32 desc_size;
u32 num_desc;
- u8 data[0]; /* Must be last */
+ u8 data[]; /* Must be last */
};
struct cudbg_qdesc_info {
u32 qdesc_entry_size;
u32 num_queues;
- u8 data[0]; /* Must be last */
+ u8 data[]; /* Must be last */
};
#define IREG_NUM_ELEM 4
struct devlog_info {
unsigned int nentries; /* number of entries in log[] */
unsigned int first; /* first [temporal] entry in log[] */
- struct fw_devlog_e log[0]; /* Firmware Device Log */
+ struct fw_devlog_e log[]; /* Firmware Device Log */
};
/* Dump a Firmaware Device Log entry.
unsigned int rows; /* # of entries */
unsigned char width; /* size in bytes of each entry */
unsigned char skip_first; /* whether the first line is a header */
- char data[0]; /* the table data */
+ char data[]; /* the table data */
};
static inline unsigned int hex2val(char c)
struct cxgb4_tc_u32_table {
unsigned int size; /* number of entries in table */
- struct cxgb4_link table[0]; /* Jump table */
+ struct cxgb4_link table[]; /* Jump table */
};
#endif /* __CXGB4_TC_U32_PARSE_H */
rwlock_t lock;
atomic_t nfree; /* number of free entries */
struct l2t_entry *rover; /* starting point for next allocation */
- struct l2t_entry l2tab[0]; /* MUST BE LAST */
+ struct l2t_entry l2tab[]; /* MUST BE LAST */
};
static inline unsigned int vlan_prio(const struct l2t_entry *e)
struct sched_table { /* per port scheduling table */
u8 sched_size;
- struct sched_class tab[0];
+ struct sched_class tab[];
};
static inline bool can_sched(struct net_device *dev)
struct smt_data {
unsigned int smt_size;
rwlock_t lock;
- struct smt_entry smtab[0];
+ struct smt_entry smtab[];
};
struct smt_data *t4_init_smt(void);
__be32 cmd_nsge;
__be32 len0;
__be64 addr0;
- struct ulptx_sge_pair sge[0];
+ struct ulptx_sge_pair sge[];
};
struct ulptx_idata {
struct fw_flowc_wr {
__be32 op_to_nparams;
__be32 flowid_len16;
- struct fw_flowc_mnemval mnemval[0];
+ struct fw_flowc_mnemval mnemval[];
};
#define FW_FLOWC_WR_NPARAMS_S 0
unsigned int base; /* base index */
unsigned int next; /* next possible free index */
spinlock_t lock; /* ppm pool lock */
- unsigned long bmap[0];
+ unsigned long bmap[];
} ____cacheline_aligned_in_smp;
struct cxgbi_ppm {
unsigned int next;
unsigned int max_index_in_edram;
unsigned long *ppod_bmap;
- struct cxgbi_ppod_data ppod_data[0];
+ struct cxgbi_ppod_data ppod_data[];
};
#define DDP_THRESHOLD 512