On Fri, Jun 05, 2015 at 03:07:47PM +0100, Dave Martin wrote:

pl011_tx_softirq() currently uses spin_{,un}lock(), which are not
sufficient to inhibit pl011_int() from being triggered by a local
IRQ and trying to re-take the same lock.  This can lead to
deadlocks.

This patch uses the _irq() locking variants instead to ensure that
pl011_int() handling for a given port is deferred until any
pl011_tx_softirq() work for that port is complete.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Tested-by: Robin Murphy <robin.murphy@arm.com>
Cc: stable <redacted> # 4.1
---

Another candidate for v4.1 if possible (sorry!) -- I thought this change
was already in, but it went astray when I was refactoring.

Too late for 4.1, sorry.  This doesn't apply to my tty-next branch,
otherwise I would have queued it up there.  Care to redo it and mark it
for -stable, like I did above, and resend it?

thanks,

greg k-h