xhci: Fix resume issues on Renesas chips in Samsung laptops

commit 1aa9578c1a9450fb21501c4f549f5b1edb557e6d upstream.

Don Zickus <dzickus@redhat.com> writes:

Some co-workers of mine bought Samsung laptops that had mostly usb3 ports.
Those ports did not resume correctly (the driver would timeout communicating
and fail).  This led to frustration as suspend/resume is a common use for
laptops.

Poking around, I applied the reset on resume quirk to this chipset and the
resume started working.  Reloading the xhci_hcd module had been the temporary
workaround.

Change-Id: Ie198ce1659bc366c6062f2a7957ff40f8772e557
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Reported-by: Don Zickus <dzickus@redhat.com>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ipc/msg: fix race around refcount

[fixed differently in 6062a8dc0517bce23e3c2f7d2fea5e22411269a3 upstream.]

In older kernels (before v3.10) ipc_rcu_hdr->refcount was non-atomic int.
There was possuble double-free bug: do_msgsnd() calls ipc_rcu_putref() under
msq->q_perm->lock and RCU, while freequeue() calls it while it holds only
'rw_mutex', so there is no sinchronization between them. Two function
decrements '2' non-atomically, they both can get '0' as result.

do_msgsnd()					freequeue()

msq = msg_lock_check(ns, msqid);
...
ipc_rcu_getref(msq);
msg_unlock(msq);
schedule();
						(caller locks spinlock)
						expunge_all(msq, -EIDRM);
						ss_wakeup(&msq->q_senders, 1);
						msg_rmid(ns, msq);
						msg_unlock(msq);
ipc_lock_by_ptr(&msq->q_perm);
ipc_rcu_putref(msq);				ipc_rcu_putref(msq);
< both may get get --(...)->refcount == 0 >

This patch locks ipc_lock and RCU around ipc_rcu_putref in freequeue.
( RCU protects memory for spin_unlock() )

Similar bugs might be in other users of ipc_rcu_putref().

In the mainline this has been fixed in v3.10 indirectly in commmit
6062a8dc0517bce23e3c2f7d2fea5e22411269a3
("ipc,sem: fine grained locking for semtimedop") by Rik van Riel.
That commit optimized locking and converted refcount into atomic.

I'm not sure that anybody should care about this bug: it's very-very unlikely
and no longer exists in actual mainline. I've found this just by looking into
the code, probably this never happens in real life.

Change-Id: I567a326791d15ea04ef116b09d240bbc7048334b
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Linux 3.4.85

Change-Id: Ifb96729833ab5aacdf75af040d53373e3d5a8632