Bug 863728 – sys-cluster/drbd-utils-9.19.1 fails to compile (lto): shared_main.c:60:22: error: type of [-Werror=lto-type-mismatch]

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2022-08-05 07:10:12 UTC]

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

Issue: sys-cluster/drbd-utils-9.19.1 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 2022-08-05 07:10:14 UTC]

Created attachment 797830 [details]
build.log

build log and emerge --info

[Comment 2 Larry the Git Cow 2023-06-13 18:00:18 UTC]

The bug has been referenced in the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=02512e1d120272ad4e035959fa4014a8df7a28fc

commit 02512e1d120272ad4e035959fa4014a8df7a28fc
Author:     Sam James <[e-mail]>
AuthorDate: 2023-06-13 17:42:05 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2023-06-13 17:59:50 +0000

    sys-cluster/drbd-utils: add 9.23.1
    
    Bug: https://bugs.gentoo.org/863728
    Closes: https://bugs.gentoo.org/828057
    Closes: https://bugs.gentoo.org/828058
    Closes: https://bugs.gentoo.org/832021
    Closes: https://bugs.gentoo.org/880973
    Signed-off-by: Sam James <[e-mail]>

 sys-cluster/drbd-utils/Manifest                    |   1 +
 sys-cluster/drbd-utils/drbd-utils-9.23.1.ebuild    | 129 +++++++++++++++++++++
 .../files/drbd-utils-9.23.1-respect-flags.patch    |  21 ++++
 3 files changed, 151 insertions(+)

[Comment 3 Larry the Git Cow 2024-01-01 00:12:29 UTC]

The bug has been referenced in the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=6fe332967f8bd8e14bb8734f7e5c714e5d0de06e

commit 6fe332967f8bd8e14bb8734f7e5c714e5d0de06e
Author:     Eli Schwartz <[e-mail]>
AuthorDate: 2023-12-31 22:46:33 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2024-01-01 00:12:14 +0000

    sys-cluster/drbd-utils: suppress LTO
    
    It fails to build:
    
    ```
    x86_64-pc-linux-gnu-gcc -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -fstack-clash-protection -Wformat -Werror=format-security -flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Werror=implicit-function-declaration -Werror=implicit-int -Werror=int-conversion -Werror=incompatible-pointer-types -Wall -I../../drbd-headers -I.. -I. -I../shared   -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0  -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0 -o drbdadm drbdadm_scanner.o drbdadm_parser.o drbdadm_postparse.o drbdadm_main.o drbdadm_adjust.o drbdadm_dump.o drbdtool_common.o drbdadm_usage_cnt.o drbd_buildtag.o registry.o config_flags.o libnla.o drbd_nla.o shared_tool.o shared_main.o shared_parser.o libgenl.o drbdadm_linux.o drbdtool_common_linux.o path_linux.o shared_linux.o
    ../shared/shared_main.c:60:22: error: type of ‘ifreq_list’ does not match original declaration [-Werror=lto-type-mismatch]
       60 | extern struct ifreq *ifreq_list;
          |                      ^
    drbdadm_main.c:150:15: note: ‘ifreq_list’ was previously declared here
      150 | struct ifreq *ifreq_list = NULL;
          |               ^
    drbdadm_main.c:150:15: note: code may be misoptimized unless ‘-fno-strict-aliasing’ is used
    lto1: some warnings being treated as errors
    lto-wrapper: fatal error: x86_64-pc-linux-gnu-gcc returned 1 exit status
    ```
    
    Bug: https://bugs.gentoo.org/863728
    Signed-off-by: Eli Schwartz <[e-mail]>
    Signed-off-by: Sam James <[e-mail]>

 sys-cluster/drbd-utils/drbd-utils-9.25.0-r1.ebuild | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)