Commit c66d52b1 authored by Liguang Zhang's avatar Liguang Zhang Committed by Catalin Marinas
Browse files

firmware: arm_sdei: fix possible double-lock on hibernate error path 



We call sdei_reregister_event() with sdei_list_lock held, if the register
fails we call sdei_event_destroy() which also acquires sdei_list_lock
thus creating A-A deadlock.

Add '_llocked' to sdei_reregister_event(), to indicate the list lock
is held, and add a _llocked variant of sdei_event_destroy().

Fixes: da351827 ("firmware: arm_sdei: Add support for CPU and system power states")
Signed-off-by: default avatarLiguang Zhang <zhangliguang@linux.alibaba.com>
[expanded subject, added wrappers instead of duplicating contents]
Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 6ded0b61

drivers/firmware/arm_sdei.c

+13 −6
Original line number Diff line number Diff line
@@ -280,13 +280,12 @@ static struct sdei_event *sdei_event_create(u32 event_num, 
	return event;

}



static void sdei_event_destroy(struct sdei_event *event)

static void sdei_event_destroy_llocked(struct sdei_event *event)

{

	lockdep_assert_held(&sdei_events_lock);

	lockdep_assert_held(&sdei_list_lock);



	spin_lock(&sdei_list_lock);

	list_del(&event->list);

	spin_unlock(&sdei_list_lock);



	if (event->type == SDEI_EVENT_TYPE_SHARED)

		kfree(event->registered);
@@ -296,6 +295,13 @@ static void sdei_event_destroy(struct sdei_event *event) 
	kfree(event);

}



static void sdei_event_destroy(struct sdei_event *event)

{

	spin_lock(&sdei_list_lock);

	sdei_event_destroy_llocked(event);

	spin_unlock(&sdei_list_lock);

}



static int sdei_api_get_version(u64 *version)

{

	return invoke_sdei_fn(SDEI_1_0_FN_SDEI_VERSION, 0, 0, 0, 0, 0, version);
@@ -643,16 +649,17 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) 
}

EXPORT_SYMBOL(sdei_event_register);



static int sdei_reregister_event(struct sdei_event *event)

static int sdei_reregister_event_llocked(struct sdei_event *event)

{

	int err;



	lockdep_assert_held(&sdei_events_lock);

	lockdep_assert_held(&sdei_list_lock);



	err = _sdei_event_register(event);

	if (err) {

		pr_err("Failed to re-register event %u\n", event->event_num);

		sdei_event_destroy(event);

		sdei_event_destroy_llocked(event);

		return err;

	}
@@ -681,7 +688,7 @@ static int sdei_reregister_shared(void) 
			continue;



		if (event->reregister) {

			err = sdei_reregister_event(event);

			err = sdei_reregister_event_llocked(event);

			if (err)

				break;

		}

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