[PATCH v2 1/3] virtio_console: Fix locking of vtermno.
From: Miche Baker-Harvey <hidden>
Date: 2011-11-08 19:29:54
Subsystem:
char and misc drivers, the rest, virtio console driver · Maintainers:
Arnd Bergmann, Greg Kroah-Hartman, Linus Torvalds, Amit Shah
Some modifications of vtermno were not done under the spinlock. Moved assignment from vtermno and increment of vtermno together, putting both under the spinlock. Revert vtermno on failure. Signed-off-by: Miche Baker-Harvey <redacted> --- drivers/char/virtio_console.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 8e3c46d..9722e76 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c@@ -987,18 +987,21 @@ int init_port_console(struct port *port) * pointers. The final argument is the output buffer size: we * can do any size, so we put PAGE_SIZE here. */ - port->cons.vtermno = pdrvdata.next_vtermno; + spin_lock_irq(&pdrvdata_lock); + port->cons.vtermno = pdrvdata.next_vtermno++; + spin_unlock_irq(&pdrvdata_lock); port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE); + spin_lock_irq(&pdrvdata_lock); if (IS_ERR(port->cons.hvc)) { ret = PTR_ERR(port->cons.hvc); dev_err(port->dev, "error %d allocating hvc for port\n", ret); port->cons.hvc = NULL; + port->cons.vtermno = pdrvdata.next_vtermno--; + spin_unlock_irq(&pdrvdata_lock); return ret; } - spin_lock_irq(&pdrvdata_lock); - pdrvdata.next_vtermno++; list_add_tail(&port->cons.list, &pdrvdata.consoles); spin_unlock_irq(&pdrvdata_lock); port->guest_connected = true;