From: Roger Pau Monne <roger.pau@citrix.com>
Date: Mon, 27 Jul 2020 09:13:40 +0000 (+0200)
Subject: xen/balloon: make the balloon wait interruptible
X-Git-Tag: v5.7.16~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bdea0200336fcacf4e220275c826fe9fd66bc3e9;p=thirdparty%2Fkernel%2Fstable.git

xen/balloon: make the balloon wait interruptible

commit 88a479ff6ef8af7f07e11593d58befc644244ff7 upstream.

So it can be killed, or else processes can get hung indefinitely
waiting for balloon pages.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200727091342.52325-3-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 8f3becb2c01e6..a932e75f44fcc 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -569,11 +569,13 @@ static int add_ballooned_pages(int nr_pages)
 	if (xen_hotplug_unpopulated) {
 		st = reserve_additional_memory();
 		if (st != BP_ECANCELED) {
+			int rc;
+
 			mutex_unlock(&balloon_mutex);
-			wait_event(balloon_wq,
+			rc = wait_event_interruptible(balloon_wq,
 				   !list_empty(&ballooned_pages));
 			mutex_lock(&balloon_mutex);
-			return 0;
+			return rc ? -ENOMEM : 0;
 		}
 	}