From: Stefan Richter 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 Cc: Greg KH Signed-off-by: Andrew Morton --- drivers/ieee1394/nodemgr.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff -puN drivers/ieee1394/nodemgr.c~ieee1394-nodemgr-fix-rwsem-recursion drivers/ieee1394/nodemgr.c --- a/drivers/ieee1394/nodemgr.c~ieee1394-nodemgr-fix-rwsem-recursion +++ a/drivers/ieee1394/nodemgr.c @@ -1316,6 +1316,7 @@ static void nodemgr_node_scan(struct hos } +/* 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 @@ static void nodemgr_resume_ne(struct nod } +/* 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 @@ static void nodemgr_update_pdrv(struct n up_write(&ud->device.bus->subsys.rwsem); } } - up_read(&class->subsys.rwsem); } @@ -1420,6 +1419,8 @@ static void nodemgr_irm_write_bc(struct } +/* 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; _