mfd: qcom-pm8xxx: Fix potential deadlock on &chip->pm_irq_lock
As &chip->pm_irq_lock is acquired by pm8xxx_irq_handler() under irq
context, other process context code should disable irq before acquiring
the lock.
Since .irq_set_type and .irq_get_irqchip_state callbacks are generally
executed from process context without irq disabled by default, the same
lock acquision should disable irq.
Possible deadlock scenario
pm8xxx_irq_set_type()
-> pm8xxx_config_irq()
-> spin_lock(&chip->pm_irq_lock)
<irq interrupt>
-> pm8xxx_irq_handler()
-> pm8xxx_irq_master_handler()
-> pm8xxx_irq_block_handler()
-> pm8xxx_read_block_irq()
-> spin_lock(&chip->pm_irq_lock) (deadlock here)
This flaw was found using an experimental static analysis tool we are
developing for irq-related deadlock.
Fix the potential deadlock by spin_lock_irqsave().
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Link: https://lore.kernel.org/r/20230720071330.50382-1-dg573847474@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>