From 14a0d635d18d0fb552dcc979d6d25106e6541f2e Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 26 Mar 2014 14:32:51 +0100 Subject: usbnet: include wait queue head in device structure This fixes a race which happens by freeing an object on the stack. Quoting Julius: > The issue is > that it calls usbnet_terminate_urbs() before that, which temporarily > installs a waitqueue in dev->wait in order to be able to wait on the > tasklet to run and finish up some queues. The waiting itself looks > okay, but the access to 'dev->wait' is totally unprotected and can > race arbitrarily. I think in this case usbnet_bh() managed to succeed > it's dev->wait check just before usbnet_terminate_urbs() sets it back > to NULL. The latter then finishes and the waitqueue_t structure on its > stack gets overwritten by other functions halfway through the > wake_up() call in usbnet_bh(). The fix is to just not allocate the data structure on the stack. As dev->wait is abused as a flag it also takes a runtime PM change to fix this bug. Signed-off-by: Oliver Neukum Reported-by: Grant Grundler Tested-by: Grant Grundler Signed-off-by: David S. Miller --- include/linux/usb/usbnet.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/usb') diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h index e303eef94dd..0662e98fef7 100644 --- a/include/linux/usb/usbnet.h +++ b/include/linux/usb/usbnet.h @@ -30,7 +30,7 @@ struct usbnet { struct driver_info *driver_info; const char *driver_name; void *driver_priv; - wait_queue_head_t *wait; + wait_queue_head_t wait; struct mutex phy_mutex; unsigned char suspend_count; unsigned char pkt_cnt, pkt_err; -- cgit v1.2.3-70-g09d2