This is a note to let you know that I've just added the patch titled
usb: cdnsp: Fix deadlock issue during using NCM gadget
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-cdnsp-fix-deadlock-issue-during-using-ncm-gadget.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 58f2fcb3a845fcbbad2f3196bb37d744e0506250 Mon Sep 17 00:00:00 2001
From: Pawel Laszczak <pawell@xxxxxxxxxxx>
Date: Wed, 8 Nov 2023 10:31:25 +0100
Subject: usb: cdnsp: Fix deadlock issue during using NCM gadget
From: Pawel Laszczak <pawell@xxxxxxxxxxx>
commit 58f2fcb3a845fcbbad2f3196bb37d744e0506250 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.
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>
Link: https://lore.kernel.org/r/20231108093125.224963-1-pawell@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/cdns3/cdnsp-ring.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/usb/cdns3/cdnsp-ring.c
+++ b/drivers/usb/cdns3/cdnsp-ring.c
@@ -1522,6 +1522,7 @@ irqreturn_t cdnsp_thread_irq_handler(int
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)) {
@@ -1534,6 +1535,7 @@ irqreturn_t cdnsp_thread_irq_handler(int
cdnsp_died(pdev);
spin_unlock_irqrestore(&pdev->lock, flags);
+ local_bh_enable();
return IRQ_HANDLED;
}
@@ -1550,6 +1552,7 @@ irqreturn_t cdnsp_thread_irq_handler(int
cdnsp_update_erst_dequeue(pdev, event_ring_deq, 1);
spin_unlock_irqrestore(&pdev->lock, flags);
+ local_bh_enable();
return IRQ_HANDLED;
}
Patches currently in stable-queue which might be from pawell@xxxxxxxxxxx are
queue-6.1/usb-cdnsp-fix-deadlock-issue-during-using-ncm-gadget.patch
