From: Bjørn Mork <bjorn@mork.no>
Date: Wed, 9 May 2012 11:53:21 +0000 (+0200)
Subject: USB: cdc-wdm: poll must return POLLHUP if device is gone
X-Git-Tag: firefly_0821_release~7541^2~1146
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bfd6d6af769c5cd62aa9ed75b038ea3d234b090b;p=firefly-linux-kernel-4.4.55.git

USB: cdc-wdm: poll must return POLLHUP if device is gone

commit 616b6937e348ef2b4c6ea5fef2cd3c441145efb0 upstream.

Else the poll will be restarted indefinitely in a tight loop,
preventing final device cleanup.

Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 00b7bf9a20ce..5a244cfbeb42 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -511,7 +511,7 @@ static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 
 	spin_lock_irqsave(&desc->iuspin, flags);
 	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
-		mask = POLLERR;
+		mask = POLLHUP | POLLERR;
 		spin_unlock_irqrestore(&desc->iuspin, flags);
 		goto desc_out;
 	}