Bug 878145 – sci-libs/gloo-2022.05.18-r1 fails to compile: ethtool.h:2088:17: error: flexible array member ethtool_link_settings::link_mode_masks not at end of struct gloo::getInterfaceSpeedGLinkSettings(int, ifreq)::<unnamed>

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Agostino Sarubbo 2022-10-24 06:57:30 UTC]

https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: sci-libs/gloo-2022.05.18 fails to compile (lto).
Discovered on: amd64 (internal ref: lto_tinderbox)

NOTE:
This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing

Here is a bit of explanation:

-Werror=lto-type-mismatch:
User to find possible runtime issues in packages. It likely means the package is unsafe to build & use with LTO.
For projects using the same identifier but with different types across different files, they must be fixed to be consistent across the codebase.

-Werror=odr:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO. C++ code must comply with the One Definition Rule (ODR) - see https://en.cppreference.com/w/cpp/language/definition#One_Definition_Rule.

-Werror=strict-aliasing:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO.

Workarounds:
- If upstream is friendly and still active, file a bug upstream. For emulators, codecs, games, or multimedia packages, it may be worth just applying a workaround instead, as upstreams sometimes aren't receptive to these bugs (VALID FOR ALL).
- Use the new 'filter-lto' from flag-o-matic.eclass as it's likely to be unsafe with LTO (VALID FOR lto-type-mismatch - odr).
- Fix it yourself if interested, of course (VALID FOR ALL).
- Append-flags -fno-strict-aliasing (VALID FOR strict-aliasing).
- Use memcpy() but a union is sometimes suitable too (VALID FOR strict-aliasing).
- -fstrict-aliasing is implied by -O2, so this must be addressed in some form (VALID FOR strict-aliasing).

See also: https://marc.info/?l=gentoo-dev&m=165639574126280&w=2

[Comment 1 Agostino Sarubbo 2022-10-24 06:57:32 UTC]

Created attachment 825169 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2022-10-24 06:57:34 UTC]

Error(s) that match a know pattern in addition to what has been reported in the summary:


FAILED: gloo/CMakeFiles/gloo.dir/common/linux.cc.o 
/usr/include/linux/ethtool.h:2088:17: error: flexible array member ‘ethtool_link_settings::link_mode_masks’ not at end of ‘struct gloo::getInterfaceSpeedGLinkSettings(int, ifreq*)::<unnamed>’

[Comment 3 Sam James 2022-10-24 10:24:44 UTC]

It's linux-headers-6.0.

[Comment 4 Tupone Alfredo 2022-10-28 06:46:22 UTC]

See https://github.com/facebookincubator/gloo/issues/345 from debian

[Comment 5 Agostino Sarubbo 2023-01-12 09:21:37 UTC]

ci has reproduced this issue with version 2022.05.18-r1 - Updating summary.

[Comment 6 Sam James 2023-08-29 07:07:11 UTC]

https://github.com/facebookincubator/gloo/commit/10909297fedab0a680799211a299203e53515032 seems to be in 

commit a5f7949a839eeed18a4f616ea72e5661918b8c0e
Author: Alfredo Tupone <[e-mail]>
Date:   Sun Apr 9 22:05:50 2023 +0200

    sci-libs/gloo: add 2023.01.17

    Signed-off-by: Alfredo Tupone <[e-mail]>