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Message-Id: <20200921162039.493510136@linuxfoundation.org>
Date: Mon, 21 Sep 2020 18:28:13 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Oliver Neukum <oneukum@...e.com>,
syzbot+be5b5f86a162a6c281e6@...kaller.appspotmail.com
Subject: [PATCH 4.14 86/94] usblp: fix race between disconnect() and read()
From: Oliver Neukum <oneukum@...e.com>
commit 9cdabcb3ef8c24ca3a456e4db7b012befb688e73 upstream.
read() needs to check whether the device has been
disconnected before it tries to talk to the device.
Signed-off-by: Oliver Neukum <oneukum@...e.com>
Reported-by: syzbot+be5b5f86a162a6c281e6@...kaller.appspotmail.com
Link: https://lore.kernel.org/r/20200917103427.15740-1-oneukum@suse.com
Cc: stable <stable@...r.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/usb/class/usblp.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -840,6 +840,11 @@ static ssize_t usblp_read(struct file *f
if (rv < 0)
return rv;
+ if (!usblp->present) {
+ count = -ENODEV;
+ goto done;
+ }
+
if ((avail = usblp->rstatus) < 0) {
printk(KERN_ERR "usblp%d: error %d reading from printer\n",
usblp->minor, (int)avail);
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