On 9/11/2017 4:13 PM, Olivier Matz wrote:
> The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
> error:
>
> CC rte_lpm6.o
> rte_lpm6.c: In function ‘rte_lpm6_add_v1705’:
> rte_lpm6.c:442:11: error: ‘tbl_next’ may be used uninitialized in
> this function [-Werror=maybe-uninitialized]
> if (!tbl[tbl_index].valid) {
> ^
> rte_lpm6.c:521:29: note: ‘tbl_next’ was declared here
> struct rte_lpm6_tbl_entry *tbl_next;
> ^~~~~~~~
>
> This is a false positive from gcc. Fix it by initializing tbl_next
> to NULL.
This is hard to trace, and it seems there is a way to have it, not sure
practically possible:
rte_lpm6_add_v1705
add_step
if (depth <= bits_covered) {
...
return 0 <--- so tbl_next stays untouched.
tbl = tbl_next
add_step
tbl[tbl_index]
So same comment as previous, if there is a practically available path,
this patch makes it harder to find by hiding compiler warning, so adding
maintainer for decision.
>
> Signed-off-by: Olivier Matz <olivier.m...@6wind.com>
> ---
> lib/librte_lpm/rte_lpm6.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/librte_lpm/rte_lpm6.c b/lib/librte_lpm/rte_lpm6.c
> index b4a7df348..f9496fe1b 100644
> --- a/lib/librte_lpm/rte_lpm6.c
> +++ b/lib/librte_lpm/rte_lpm6.c
> @@ -518,7 +518,7 @@ rte_lpm6_add_v1705(struct rte_lpm6 *lpm, uint8_t *ip,
> uint8_t depth,
> uint32_t next_hop)
> {
> struct rte_lpm6_tbl_entry *tbl;
> - struct rte_lpm6_tbl_entry *tbl_next;
> + struct rte_lpm6_tbl_entry *tbl_next = NULL;
> int32_t rule_index;
> int status;
> uint8_t masked_ip[RTE_LPM6_IPV6_ADDR_SIZE];
>
