As kcs_bmc_handle_event() is executed inside both a timer and a hardirq,
it should disable irq before lock acquisition otherwise deadlock could
happen if the timmer is preemtped by the irq.
Possible deadlock scenario:
aspeed_kcs_check_obe() (timer)
-> kcs_bmc_handle_event()
-> spin_lock(&kcs_bmc->lock)
<irq interruption>
-> aspeed_kcs_irq()
-> kcs_bmc_handle_event()
-> spin_lock(&kcs_bmc->lock) (deadlock here)
This flaw was found using an experimental static analysis tool we are
developing for irq-related deadlock.
The tentative patch fix the potential deadlock by spin_lock_irqsave()
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Message-Id: <20230627152449.36093-1-dg573847474@gmail.com>
Signed-off-by: Corey Minyard <minyard@acm.org>
b02bb79eee