Bug 854225 – app-crypt/mit-krb5-1.21.2 fails to compile (lto): kadmin_ct.c:98:13: error: type of kadmin_keytab_remove does not match original declaration [-Werror=lto-type-mismatch]

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Agostino Sarubbo 2022-06-25 08:26:32 UTC]

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

Issue: app-crypt/mit-krb5-1.20 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

[Comment 1 Agostino Sarubbo 2022-06-25 08:26:35 UTC]

Created attachment 787568 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2022-07-26 09:00:13 UTC]

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 3 Arniii 2024-01-25 04:41:13 UTC]

reproducible with =app-crypt/mit-krb5-1.20.1::gentoo

[Comment 4 Agostino Sarubbo 2024-02-11 07:23:12 UTC]

lto_tinderbox has reproduced this issue with version 1.21.2 - Updating summary.

[Comment 5 Larry the Git Cow 2024-03-01 03:42:07 UTC]

The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=953dc612be2c7c96ef5a5d1f0160253f0485e3c8

commit 953dc612be2c7c96ef5a5d1f0160253f0485e3c8
Author:     Sam James <[e-mail]>
AuthorDate: 2024-03-01 03:41:02 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2024-03-01 03:41:58 +0000

    app-crypt/mit-krb5: filter LTO
    
    Suffers from lto-type-mismatch. The codebase is pretty old.
    
    Closes: https://bugs.gentoo.org/854225
    Signed-off-by: Sam James <[e-mail]>

 app-crypt/mit-krb5/mit-krb5-1.21.2.ebuild | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

[Comment 6 Sam James 2024-03-01 07:56:20 UTC]

Also, Eli attempted to report this one upstream but it's stuck in mail purgatory.