Messages in this thread Patch in this message | | | Date | Tue, 12 Oct 2021 16:35:21 +0800 | Subject | [PATCH] sched/scs: Reset the shadow stack when idle_task_exit | From | Woody Lin <> |
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There was a 'init_idle' that resets scs sp to base, but is removed by f1a0a376ca0c. Without the resetting, the hot-plugging implemented by cpu_psci_cpu_boot will use the previous scs sp as new base when starting up a CPU core, so the usage on scs page is being stacked up until overflow.
This only happens on idle task since __cpu_up is using idle task as the main thread to start up a CPU core, so the overflow can be fixed by resetting scs sp to base in 'idle_task_exit'.
Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled") Signed-off-by: Woody Lin <woodylin@google.com> --- kernel/sched/core.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1bba4128a3e6..f21714ea3db8 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 */ } -- 2.33.0.882.g93a45727a2-goog
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