| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 86/94] usblp: fix race between disconnect() and read() | Date | Mon, 21 Sep 2020 18:28:13 +0200 |
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From: Oliver Neukum <oneukum@suse.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@suse.com> Reported-by: syzbot+be5b5f86a162a6c281e6@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20200917103427.15740-1-oneukum@suse.com Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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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