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Commit 96fe5061 authored by Woody Lin's avatar Woody Lin Committed by Greg Kroah-Hartman
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sched/scs: Reset the shadow stack when idle_task_exit



[ Upstream commit 63acd42c ]

Commit f1a0a376 ("sched/core: Initialize the idle task with
preemption disabled") removed the init_idle() call from
idle_thread_get(). This was the sole call-path on hotplug that resets
the Shadow Call Stack (scs) Stack Pointer (sp).

Not resetting the scs-sp leads to scs overflow after enough hotplug
cycles. Therefore add an explicit scs_task_reset() to the hotplug code
to make sure the scs-sp does get reset on hotplug.

Fixes: f1a0a376 ("sched/core: Initialize the idle task with preemption disabled")
Signed-off-by: default avatarWoody Lin <woodylin@google.com>
[peterz: Changelog]
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/20211012083521.973587-1-woodylin@google.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 96f0aebf
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