ieee1394: nodemgr: fix rwsem recursion
nodemgr_update_pdrv grabbed an rw semaphore (as reader) which was
already taken by its caller's caller, nodemgr_probe_ne (as reader too).
Reported by Miles Lane, call path pointed out by Arjan van de Ven.
FIXME:
Shouldn't we rather use class->sem there, not class->subsys.rwsem?
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c
index eabc51b..f087f7e 100644
--- a/drivers/ieee1394/nodemgr.c
+++ b/drivers/ieee1394/nodemgr.c
@@ -1316,6 +1316,7 @@
}
+/* Caller needs to hold nodemgr_ud_class.subsys.rwsem as reader. */
static void nodemgr_suspend_ne(struct node_entry *ne)
{
struct class_device *cdev;
@@ -1368,15 +1369,14 @@
}
+/* Caller needs to hold nodemgr_ud_class.subsys.rwsem as reader. */
static void nodemgr_update_pdrv(struct node_entry *ne)
{
struct unit_directory *ud;
struct hpsb_protocol_driver *pdrv;
- struct class *class = &nodemgr_ud_class;
struct class_device *cdev;
- down_read(&class->subsys.rwsem);
- list_for_each_entry(cdev, &class->children, node) {
+ list_for_each_entry(cdev, &nodemgr_ud_class.children, node) {
ud = container_of(cdev, struct unit_directory, class_dev);
if (ud->ne != ne || !ud->device.driver)
continue;
@@ -1389,7 +1389,6 @@
up_write(&ud->device.bus->subsys.rwsem);
}
}
- up_read(&class->subsys.rwsem);
}
@@ -1420,6 +1419,8 @@
}
+/* Caller needs to hold nodemgr_ud_class.subsys.rwsem as reader because the
+ * calls to nodemgr_update_pdrv() and nodemgr_suspend_ne() here require it. */
static void nodemgr_probe_ne(struct host_info *hi, struct node_entry *ne, int generation)
{
struct device *dev;