diff options
authorTomasz Kulasek <>2016-04-04 16:45:23 +0200
committerThomas Monjalon <>2016-04-06 11:35:33 +0200
commitaf1694d94bf14371e4199d22464f214d4112b67a (patch)
parentbdf54f7a519c196784ea0c0d216da0e9dff272a7 (diff)
examples/l3fwd: fix crash with gcc 5
It seems that with gcc >5.x and -O2/-O3 optimization breaks packet grouping algorithm. When last packet pointer "lp" and "pnum->u64" buffer points the same memory buffer, high optimization can cause unpredictable results. It seems that assignment of precalculated group sizes may interfere with initialization of new group size when lp points value inside current group and didn't should be changed. With gcc >5.x and optimization we cannot be sure which assignment will be done first, so the group size can be counted incorrectly. This patch eliminates intersection of assignment of initial group size (lp[0] = 1) and precalculated group sizes when gptbl[v].idx < 4. Fixes: 94c54b4158d5 ("examples/l3fwd: rework exact-match") Signed-off-by: Tomasz Kulasek <> Acked-by: Konstantin Ananyev <>
1 files changed, 2 insertions, 2 deletions
diff --git a/examples/l3fwd/l3fwd_sse.h b/examples/l3fwd/l3fwd_sse.h
index f9cf50a..1afa1f0 100644
--- a/examples/l3fwd/l3fwd_sse.h
+++ b/examples/l3fwd/l3fwd_sse.h
@@ -283,9 +283,9 @@ port_groupx4(uint16_t pn[FWDSTEP + 1], uint16_t *lp, __m128i dp1, __m128i dp2)
/* if dest port value has changed. */
if (v != GRPMSK) {
- lp = pnum->u16 + gptbl[v].idx;
- lp[0] = 1;
pnum->u64 = gptbl[v].pnum;
+ pnum->u16[FWDSTEP] = 1;
+ lp = pnum->u16 + gptbl[v].idx;
return lp;