Re: [syzbot] [usb?] possible deadlock in digi_set_modem_signals

[Oliver Neukum <oneukum@suse.com>]

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On 31.07.26 19:15, syzbot wrote:
> If you want syzbot to run the reproducer, reply with:

#syz test: git://repo/address.git 11028ab62899


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From ce3cda5cc4df748600c37b6b5cf5964d21478e1c Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Tue, 4 Aug 2026 11:38:30 +0200
Subject: [PATCH 1/2] usb: serial: digi_accelport: annotate spinlocks

The driver holds two spinlocks at the same time.
This is perfectly safe, but confuses the validator.
Tell it manually that we know what we are doing.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/serial/digi_acceleport.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index dea039163661..a687217eadd7 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -522,7 +522,7 @@ static int digi_set_modem_signals(struct usb_serial_port *port,
 		port_priv->dp_port_num, modem_signals);
 
 	spin_lock_irqsave(&oob_priv->dp_port_lock, flags);
-	spin_lock(&port_priv->dp_port_lock);
+	spin_lock_nested(&port_priv->dp_port_lock, SINGLE_DEPTH_NESTING);
 
 	while (oob_priv->dp_write_urb_in_use) {
 		spin_unlock(&port_priv->dp_port_lock);
-- 
2.55.0