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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: da35182724 ("firmware: arm_sdei: Add support for CPU and system power states")
Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
[expanded subject, added wrappers instead of duplicating contents]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
alistair/sensors
Liguang Zhang 2020-02-21 16:35:07 +00:00 committed by Catalin Marinas
parent 6ded0b61cf
commit c66d52b102
1 changed files with 13 additions and 6 deletions
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19
drivers/firmware/arm_sdei.c
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@ -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;
}