usb: cdns3: Fix deadlock when using NCM gadget

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commit a1059896f2 upstream.

The cdns3 driver has the same NCM deadlock as fixed in cdnsp by commit
58f2fcb3a8 ("usb: cdnsp: Fix deadlock issue during using NCM gadget").

Under PREEMPT_RT the deadlock can be readily triggered by heavy network
traffic, for example using "iperf --bidir" over NCM ethernet link.

The deadlock occurs because the threaded interrupt handler gets
preempted by a softirq, but both are protected by the same spinlock.
Prevent deadlock by disabling softirq during threaded irq handler.

Cc: stable <stable@kernel.org>
Fixes: 7733f6c32e ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Ralph Siemsen <ralph.siemsen@linaro.org>
Acked-by: Peter Chen <peter.chen@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20250318-rfs-cdns3-deadlock-v2-1-bfd9cfcee732@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Ralph Siemsen 2025-03-18 11:09:32 -04:00 • committed by Greg Kroah-Hartman

parent 94df049530

commit b962395825

1 changed files with 2 additions and 0 deletions

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drivers/usb/cdns3/cdns3-gadget.c

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