On 23-11-08 10:31:25, Pawel Laszczak wrote: > The interrupt service routine registered for the gadget is a primary > handler which mask the interrupt source and a threaded handler which > handles the source of the interrupt. Since the threaded handler is > voluntary threaded, the IRQ-core does not disable bottom halves before > invoke the handler like it does for the forced-threaded handler. > > Due to changes in networking it became visible that a network gadget's > completions handler may schedule a softirq which remains unprocessed. > The gadget's completion handler is usually invoked either in hard-IRQ or > soft-IRQ context. In this context it is enough to just raise the softirq > because the softirq itself will be handled once that context is left. > In the case of the voluntary threaded handler, there is nothing that > will process pending softirqs. Which means it remain queued until > another random interrupt (on this CPU) fires and handles it on its exit > path or another thread locks and unlocks a lock with the bh suffix. > Worst case is that the CPU goes idle and the NOHZ complains about > unhandled softirqs. > > Disable bottom halves before acquiring the lock (and disabling > interrupts) and enable them after dropping the lock. This ensures that > any pending softirqs will handled right away. > > cc: <stable@xxxxxxxxxxxxxxx> > Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver") > Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx> Acked-by: Peter Chen <peter.chen@xxxxxxxxxx> Peter > --- > drivers/usb/cdns3/cdnsp-ring.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c > index 07f6068342d4..275a6a2fa671 100644 > --- a/drivers/usb/cdns3/cdnsp-ring.c > +++ b/drivers/usb/cdns3/cdnsp-ring.c > @@ -1529,6 +1529,7 @@ irqreturn_t cdnsp_thread_irq_handler(int irq, void *data) > unsigned long flags; > int counter = 0; > > + local_bh_disable(); > spin_lock_irqsave(&pdev->lock, flags); > > if (pdev->cdnsp_state & (CDNSP_STATE_HALTED | CDNSP_STATE_DYING)) { > @@ -1541,6 +1542,7 @@ irqreturn_t cdnsp_thread_irq_handler(int irq, void *data) > cdnsp_died(pdev); > > spin_unlock_irqrestore(&pdev->lock, flags); > + local_bh_enable(); > return IRQ_HANDLED; > } > > @@ -1557,6 +1559,7 @@ irqreturn_t cdnsp_thread_irq_handler(int irq, void *data) > cdnsp_update_erst_dequeue(pdev, event_ring_deq, 1); > > spin_unlock_irqrestore(&pdev->lock, flags); > + local_bh_enable(); > > return IRQ_HANDLED; > } > -- > 2.37.2 > -- Thanks, Peter Chen