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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Valentina Manea <valentina.manea.m@gmail.com>,
	Igor Kotrasinski <i.kotrasinsk@samsung.com>
Cc: Shuah Khan <shuah@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] usbip: vudc:  Don't enable IRQs prematurely
Date: Wed, 25 May 2022 15:30:13 +0300	[thread overview]
Message-ID: <Yo4hVWcZNYzKEkIQ@kili> (raw)

This code does:

	spin_unlock_irq(&udc->ud.lock);
	spin_unlock_irqrestore(&udc->lock, flags);

which does not make sense.  In theory, the first unlock could enable
IRQs and then the second _irqrestore could disable them again.  There
would be a brief momemt where IRQs were enabled improperly.

In real life, however, this function is always called with IRQs enabled
and the bug does not affect runtime.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
An alternative fix would be to make changes below and also change the
outside _irqsave/_irqrestore() to just _irq().  However, that's more
invasive and riskier with no upside.

 drivers/usb/usbip/vudc_sysfs.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/usbip/vudc_sysfs.c b/drivers/usb/usbip/vudc_sysfs.c
index d1cf6b51bf85..c95e6b2bfd32 100644
--- a/drivers/usb/usbip/vudc_sysfs.c
+++ b/drivers/usb/usbip/vudc_sysfs.c
@@ -128,7 +128,7 @@ static ssize_t usbip_sockfd_store(struct device *dev,
 			goto unlock;
 		}
 
-		spin_lock_irq(&udc->ud.lock);
+		spin_lock(&udc->ud.lock);
 
 		if (udc->ud.status != SDEV_ST_AVAILABLE) {
 			ret = -EINVAL;
@@ -150,7 +150,7 @@ static ssize_t usbip_sockfd_store(struct device *dev,
 		}
 
 		/* unlock and create threads and get tasks */
-		spin_unlock_irq(&udc->ud.lock);
+		spin_unlock(&udc->ud.lock);
 		spin_unlock_irqrestore(&udc->lock, flags);
 
 		tcp_rx = kthread_create(&v_rx_loop, &udc->ud, "vudc_rx");
@@ -173,14 +173,14 @@ static ssize_t usbip_sockfd_store(struct device *dev,
 
 		/* lock and update udc->ud state */
 		spin_lock_irqsave(&udc->lock, flags);
-		spin_lock_irq(&udc->ud.lock);
+		spin_lock(&udc->ud.lock);
 
 		udc->ud.tcp_socket = socket;
 		udc->ud.tcp_rx = tcp_rx;
 		udc->ud.tcp_tx = tcp_tx;
 		udc->ud.status = SDEV_ST_USED;
 
-		spin_unlock_irq(&udc->ud.lock);
+		spin_unlock(&udc->ud.lock);
 
 		ktime_get_ts64(&udc->start_time);
 		v_start_timer(udc);
@@ -201,12 +201,12 @@ static ssize_t usbip_sockfd_store(struct device *dev,
 			goto unlock;
 		}
 
-		spin_lock_irq(&udc->ud.lock);
+		spin_lock(&udc->ud.lock);
 		if (udc->ud.status != SDEV_ST_USED) {
 			ret = -EINVAL;
 			goto unlock_ud;
 		}
-		spin_unlock_irq(&udc->ud.lock);
+		spin_unlock(&udc->ud.lock);
 
 		usbip_event_add(&udc->ud, VUDC_EVENT_DOWN);
 	}
@@ -219,7 +219,7 @@ static ssize_t usbip_sockfd_store(struct device *dev,
 sock_err:
 	sockfd_put(socket);
 unlock_ud:
-	spin_unlock_irq(&udc->ud.lock);
+	spin_unlock(&udc->ud.lock);
 unlock:
 	spin_unlock_irqrestore(&udc->lock, flags);
 	mutex_unlock(&udc->ud.sysfs_lock);
-- 
2.35.1


             reply	other threads:[~2022-05-25 12:30 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-25 12:30 Dan Carpenter [this message]
2022-05-25 15:13 ` [PATCH] usbip: vudc: Don't enable IRQs prematurely Shuah Khan

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