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authorJuergen Gross <jgross@suse.com>2019-10-07 10:43:30 +0200
committerJuergen Gross <jgross@suse.com>2019-10-07 10:43:30 +0200
commitc8241d2875fce8462868f03159d75fed9f16e2f7 (patch)
tree6f3444522ae1d58c3db52203ceb81172dbed5b78
parent76533c1d0db88743166e3b8fb1e7b75cdc9bc18d (diff)
xen/xenbus: fix self-deadlock after killing user process
(bsc#1065600). suse-commit: 76e2ca6dab98b6a44fae879c348b384dec604db7
-rw-r--r--drivers/xen/xenbus/xenbus_dev_frontend.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index 54a9ab285ab9..66d8ae826513 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -55,6 +55,7 @@
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/miscdevice.h>
+#include <linux/workqueue.h>
#include <xen/xenbus.h>
#include <xen/xen.h>
@@ -113,6 +114,8 @@ struct xenbus_file_priv {
wait_queue_head_t read_waitq;
struct kref kref;
+
+ struct work_struct wq;
};
/* Read out any raw xenbus messages queued up. */
@@ -297,14 +300,14 @@ static void watch_fired(struct xenbus_watch *watch,
mutex_unlock(&adap->dev_data->reply_mutex);
}
-static void xenbus_file_free(struct kref *kref)
+static void xenbus_worker(struct work_struct *wq)
{
struct xenbus_file_priv *u;
struct xenbus_transaction_holder *trans, *tmp;
struct watch_adapter *watch, *tmp_watch;
struct read_buffer *rb, *tmp_rb;
- u = container_of(kref, struct xenbus_file_priv, kref);
+ u = container_of(wq, struct xenbus_file_priv, wq);
/*
* No need for locking here because there are no other users,
@@ -330,6 +333,18 @@ static void xenbus_file_free(struct kref *kref)
kfree(u);
}
+static void xenbus_file_free(struct kref *kref)
+{
+ struct xenbus_file_priv *u;
+
+ /*
+ * We might be called in xenbus_thread().
+ * Use workqueue to avoid deadlock.
+ */
+ u = container_of(kref, struct xenbus_file_priv, kref);
+ schedule_work(&u->wq);
+}
+
static struct xenbus_transaction_holder *xenbus_get_transaction(
struct xenbus_file_priv *u, uint32_t tx_id)
{
@@ -626,6 +641,7 @@ static int xenbus_file_open(struct inode *inode, struct file *filp)
INIT_LIST_HEAD(&u->watches);
INIT_LIST_HEAD(&u->read_buffers);
init_waitqueue_head(&u->read_waitq);
+ INIT_WORK(&u->wq, xenbus_worker);
mutex_init(&u->reply_mutex);
mutex_init(&u->msgbuffer_mutex);