From akpm@osdl.org Mon Jan 9 01:09:07 2006 Message-Id: <200601090905.k09953Iv027215@shell0.pdx.osdl.net> From: "Michael Richardson" Subject: device_shutdown can loop if the driver frees itself To: mcr@sandelman.ottawa.on.ca, dhowells@redhat.com, greg@kroah.com, mcr@marajade.sandelman.ca, mochel@digitalimplant.org, mm-commits@vger.kernel.org Date: Mon, 09 Jan 2006 01:04:51 -0800 From: "Michael Richardson" This patch changes device_shutdown() to use the newly introduced safe reverse list traversal. We experienced loops on system reboot if we had removed and re-inserted our device from the device list. We noticed this problem on PPC405. Our PCI IDE device comes and goes a lot. Our hypothesis was that there was a loop caused by the driver->shutdown freeing memory. It is possible that we do something wrong as well, but being unable to reboot is kind of nasty. Signed-off-by: Michael Richardson Cc: Patrick Mochel Cc: David Howells Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/base/power/shutdown.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- gregkh-2.6.orig/drivers/base/power/shutdown.c +++ gregkh-2.6/drivers/base/power/shutdown.c @@ -35,10 +35,10 @@ extern int sysdev_shutdown(void); */ void device_shutdown(void) { - struct device * dev; + struct device * dev, *devn; down_write(&devices_subsys.rwsem); - list_for_each_entry_reverse(dev, &devices_subsys.kset.list, + list_for_each_entry_safe_reverse(dev, devn, &devices_subsys.kset.list, kobj.entry) { if (dev->bus && dev->bus->shutdown) { dev_dbg(dev, "shutdown\n");