From: Woody Lin woodylin@google.com
stable inclusion from stable-5.10.76 commit 96fe5061291d9e9734abf6bb187ef7532824522d bugzilla: 182988 https://gitee.com/openeuler/kernel/issues/I4IAHF
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 63acd42c0d4942f74710b11c38602fb14dea7320 ]
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@google.com [peterz: Changelog] Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Valentin Schneider valentin.schneider@arm.com Link: https://lore.kernel.org/r/20211012083521.973587-1-woodylin@google.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- kernel/sched/core.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 685cb8c215d8..989cf0f3e718 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6917,6 +6917,7 @@ 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 */ }