Subject: [next-20251219]Build Failure on IBM Power system

From: Venkat Rao Bagalkote <[email-masked]>
Date: Thu, 1 Jan 2026 10:50:02 +0530

Greetings!!!

IBM CI has reported a build failure on next-20251219 build.

Build Failure:

cc1: some warnings being treated as errors
make[4]: *** [scripts/Makefile.build:287: kernel/sched/build_policy.o] 
Error 1
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [scripts/Makefile.build:556: kernel/sched] Error 2
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [scripts/Makefile.build:556: kernel] Error 2
make[2]: *** Waiting for unfinished jobs....

IBM CI has bisected this issue to below commit.

5d1f0b2f278eb55aebe29210fbc8f352c53497d6 is the first bad commit
commit 5d1f0b2f278eb55aebe29210fbc8f352c53497d6
Author: Peter Zijlstra <[email-masked]>
Date:   Wed Dec 10 09:06:50 2025 +0100

Bisection Logs:

#git bisect log
git bisect log
git bisect start
# status: waiting for both good and bad commits
# good: [8f0b4cce4481fb22653697cced8d0d04027cb1e8] Linux 6.19-rc1
git bisect good 8f0b4cce4481fb22653697cced8d0d04027cb1e8
# status: waiting for bad commit, 1 good commit known
# bad: [cc3aa43b44bdb43dfbac0fcb51c56594a11338a8] Add linux-next 
specific files for 20251219
git bisect bad cc3aa43b44bdb43dfbac0fcb51c56594a11338a8
# good: [600a692707acda49434d6c2c03dda20f46e09749] Merge branch 
'libcrypto-next' of 
https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git
git bisect good 600a692707acda49434d6c2c03dda20f46e09749
# good: [816a7181ac38fd22243edb557537b2aecb9eeb76] Merge branch 
'drm-xe-next' of https://gitlab.freedesktop.org/drm/xe/kernel.git
git bisect good 816a7181ac38fd22243edb557537b2aecb9eeb76
# good: [7157d55093613cf905cfd665772eae35d5c388f0] Merge branch 
'for-next' of 
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git
git bisect good 7157d55093613cf905cfd665772eae35d5c388f0
# bad: [52af2cfd69d264f1a370693966acf5d96943add8] Merge branch 
'extcon-next' of 
https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/extcon.git
git bisect bad 52af2cfd69d264f1a370693966acf5d96943add8
# bad: [502068d3b65cc8695f8da83a7f19c90805c958ca] next-20251217/tip
git bisect bad 502068d3b65cc8695f8da83a7f19c90805c958ca
# bad: [c06f166058309936567065e737f6f5d9609a1a87] Merge branch into 
tip/master: 'sched/core'
git bisect bad c06f166058309936567065e737f6f5d9609a1a87
# good: [e2292f5c21542354246687d8e3e48a58b046e27b] Merge branch into 
tip/master: 'irq/msi'
git bisect good e2292f5c21542354246687d8e3e48a58b046e27b
# good: [fb9a7458e508ef1beae8d80ee40c2cd1b5b45f3a] sched/fair: Clean up 
comments in 'struct cfs_rq'
git bisect good fb9a7458e508ef1beae8d80ee40c2cd1b5b45f3a
# good: [527a521029c3edd38fb9fc96cd58e3fd7393d28e] sched/fair: Sort out 
'blocked_load*' namespace noise
git bisect good 527a521029c3edd38fb9fc96cd58e3fd7393d28e
# good: [7ac422cf7b16ec524bcd8e017459e328a4103f63] 
perf/x86/intel/cstate: Add Diamond Rapids support
git bisect good 7ac422cf7b16ec524bcd8e017459e328a4103f63
# bad: [5d1f0b2f278eb55aebe29210fbc8f352c53497d6] sched/core: Rework 
sched_class::wakeup_preempt() and rq_modified_*()
git bisect bad 5d1f0b2f278eb55aebe29210fbc8f352c53497d6
# first bad commit: [5d1f0b2f278eb55aebe29210fbc8f352c53497d6] 
sched/core: Rework sched_class::wakeup_preempt() and rq_modified_*()

If you happen to fix this issue, please add below tag.

Reported-by: Venkat Rao Bagalkote <[email-masked]>

Regards,

Venkat.