> -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Tomasz Kulasek > Sent: Monday, April 04, 2016 3:45 PM > To: dev at dpdk.org > Subject: [dpdk-dev] [PATCH] examples/l3fwd: fix segfault with gcc 5.x > > 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 <tomaszx.kulasek at intel.com> > --- > examples/l3fwd/l3fwd_sse.h | 4 ++-- > 1 file 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; > --
Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com> > 1.7.9.5
