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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2022-02-18 20:32:45 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-03-02 13:32:05 +0300
commite2ccf7494b6b43750f804d9d5e2d98da47e741cb (patch)
tree8cd44d4bfc65401ad4fec82b0edbfbe1771014c5 /drivers/usb/dwc3
parent9f9c43284c4de6e2d18540152d756679fbe89334 (diff)
downloadlinux-e2ccf7494b6b43750f804d9d5e2d98da47e741cb.tar.xz
usb: dwc3: gadget: Let the interrupt handler disable bottom halves.
commit 84918a89d6efaff075de570b55642b6f4ceeac6d upstream. 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. Link: https://lkml.kernel.org/r/c2a64979-73d1-2c22-e048-c275c9f81558@samsung.com Fixes: e5f68b4a3e7b0 ("Revert "usb: dwc3: gadget: remove unnecessary _irqsave()"") Cc: stable <stable@kernel.org> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/Yg/YPejVQH3KkRVd@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/dwc3')
-rw-r--r--drivers/usb/dwc3/gadget.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 58c4b745eae1..ccc47594064f 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2904,9 +2904,11 @@ static irqreturn_t dwc3_thread_interrupt(int irq, void *_evt)
unsigned long flags;
irqreturn_t ret = IRQ_NONE;
+ local_bh_disable();
spin_lock_irqsave(&dwc->lock, flags);
ret = dwc3_process_event_buf(evt);
spin_unlock_irqrestore(&dwc->lock, flags);
+ local_bh_enable();
return ret;
}