The following commit has been merged into the sched/urgent branch of tip: Commit-ID: 63acd42c0d4942f74710b11c38602fb14dea7320 Gitweb: https://git.kernel.org/tip/63acd42c0d4942f74710b11c38602fb14dea7320 Author: Woody Lin <woodylin@xxxxxxxxxx> AuthorDate: Tue, 12 Oct 2021 16:35:21 +08:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Tue, 19 Oct 2021 17:46:11 +02:00 sched/scs: Reset the shadow stack when idle_task_exit Commit f1a0a376ca0c ("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: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled") Signed-off-by: Woody Lin <woodylin@xxxxxxxxxx> [peterz: Changelog] Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Valentin Schneider <valentin.schneider@xxxxxxx> Link: https://lore.kernel.org/r/20211012083521.973587-1-woodylin@xxxxxxxxxx --- kernel/sched/core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1bba412..f21714e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8795,6 +8795,7 @@ void idle_task_exit(void) finish_arch_post_lock_switch(); } + scs_task_reset(current); /* finish_cpu(), as ran on the BP, will clean up the active_mm state */ }
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