Peter Zijlstra 5324953c06 sched/core: Fix wakeup_preempt's next_class tracking ... Kernel test robot reported that tools/testing/selftests/kvm/hardware_disable_test was failing due to commit 704069649b ("sched/core: Rework sched_class::wakeup_preempt() and rq_modified_*()") It turns out there were two related problems that could lead to a missed preemption: - when hitting newidle balance from the idle thread, it would elevate rb->next_class from &idle_sched_class to &fair_sched_class, causing later wakeup_preempt() calls to not hit the sched_class_above() case, and not issue resched_curr(). Notably, this modification pattern should only lower the next_class, and never raise it. Create two new helper functions to wrap this. - when doing schedule_idle(), it was possible to miss (re)setting rq->next_class to &idle_sched_class, leading to the very same problem. Cc: Sean Christopherson <seanjc@google.com> Fixes: 704069649b ("sched/core: Rework sched_class::wakeup_preempt() and rq_modified_*()") Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202602122157.4e861298-lkp@intel.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260218163329.GQ1395416@noisy.programming.kicks-ass.net		2026-02-23 11:19:19 +01:00
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Makefile	…
autogroup.c	…
autogroup.h	…
build_policy.c	…
build_utility.c	…
clock.c	…
completion.c	…
core.c	sched/core: Fix wakeup_preempt's next_class tracking	2026-02-23 11:19:19 +01:00
core_sched.c	…
cpuacct.c	…
cpudeadline.c	…
cpudeadline.h	…
cpufreq.c	…
cpufreq_schedutil.c	…
cpupri.c	…
cpupri.h	…
cputime.c	…
deadline.c	…
debug.c	…
ext.c	sched/core: Fix wakeup_preempt's next_class tracking	2026-02-23 11:19:19 +01:00
ext.h	…
ext_idle.c	…
ext_idle.h	…
ext_internal.h	…
fair.c	sched/core: Fix wakeup_preempt's next_class tracking	2026-02-23 11:19:19 +01:00
features.h	…
idle.c	…
isolation.c	…
loadavg.c	…
membarrier.c	…
pelt.c	…
pelt.h	…
psi.c	…
rq-offsets.c	…
rt.c	…
sched-pelt.h	…
sched.h	sched/core: Fix wakeup_preempt's next_class tracking	2026-02-23 11:19:19 +01:00
smp.h	…
stats.c	…
stats.h	…
stop_task.c	…
swait.c	…
syscalls.c	…
topology.c	…
wait.c	…
wait_bit.c	…