On 21 Dec 2022, at 13:42, Ilya Maximets wrote:
> On 12/20/22 15:38, Ilya Maximets wrote: >> On 12/20/22 14:14, Eelco Chaudron wrote: >>> >>> >>> On 20 Dec 2022, at 14:06, David Marchand wrote: >>> >>>> On Tue, Dec 20, 2022 at 2:01 PM Eelco Chaudron <[email protected]> wrote: >>>>> I have problems building this on my fedora35 system with >>>>> gcc-11.3.1-3.fc35.x86_64: >>>>> >>>>> libtool: link: ( cd "include/openvswitch/.libs" && rm -f "libcxxtest.la" >>>>> && ln -s "../libcxxtest.la" "libcxxtest.la" ) >>>>> In file included from lib/netdev-linux-private.h:30, >>>>> from lib/netdev-afxdp.c:19: >>>>> In function ‘dp_packet_delete’, >>>>> inlined from ‘dp_packet_delete’ at lib/dp-packet.h:246:1, >>>>> inlined from ‘dp_packet_batch_add__’ at lib/dp-packet.h:775:9, >>>>> inlined from ‘dp_packet_batch_add’ at lib/dp-packet.h:783:5, >>>>> inlined from ‘netdev_afxdp_rxq_recv’ at lib/netdev-afxdp.c:894:9: >>>>> lib/dp-packet.h:260:9: error: ‘free’ called on pointer >>>>> ‘*umem.xpool.array’ with nonzero offset [8, 2558044588346441168] >>>>> [-Werror=free-nonheap-object] >>>>> 260 | free(b); >>>>> | ^~~~~~~ >>>>> >>>>> Guess it does not recognise the (b->source == DPBUF_AFXDP) statement… >>>>> >>>>> This is my build config: >>>>> >>>>> ./configure --enable-Werror --enable-usdt-probes --localstatedir=/var >>>>> --prefix=/usr --sysconfdir=/etc --enable-afxdp >>>>> >>>>> Guess this should be fixed before we enable afxdp by default? >>>> >>>> Same for me. >>>> I have been scratching my head over this report... I wonder if this is >>>> a compiler bug. >>> >>> I guess the compiler does not understand that we will always call >>> dp_packet_delete() with the source being DPBUF_AFXDP, and don’t hit the >>> free(). >>> Guess we should probably disable the warning in this specific code path. >>> >>> //Eelco >>> >> >> Meanwhile I opened a GCC bug: >> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108187 > > So, AFAICT, the issue is that implementation of the dp_packet_use_afxdp() > is part of a different translation unit (dp-packet.c) and GCC has no access > to it while processing netdev-afxdp.c, so it doesn't know that packet > source is set to DPBUF_AFXDP. Hence the warning. There are still a few > misteries around this, e.g. why the issue is not seen with -O0, but they > will likely not very important. > > I don't see a good way to fix that. We could inline a bunch of functions > from dp-packet.c, or explicitly set the source to DPBUF_AFXDP somewhere in > the realm of netdev-afxdp.c module, but I don't think that any of that is > a good solution. > > I'll add a patch to disable the warning with #pragma GCC here around the > dp_packet_batch_add() call in netdev-afxdp.c for now, unless there are > better suggestions. Clang doesn't emit this warning, so we don't need > to have a workaround for it. Sound like a good plan to me! > Best regards, Ilya Maximets. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
