3.6.11.9-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Amit Shah [ Upstream commit 96f97a83910cdb9d89d127c5ee523f8fc040a804 ] If a port gets unplugged while a user is blocked on read(), -ENODEV is returned. However, subsequent read()s returned 0, indicating there's no host-side connection (but not indicating the device went away). This also happened when a port was unplugged and the user didn't have any blocking operation pending. If the user didn't monitor the SIGIO signal, they won't have a chance to find out if the port went away. Fix by returning -ENODEV on all read()s after the port gets unplugged. write() already behaves this way. CC: Signed-off-by: Amit Shah Signed-off-by: Rusty Russell Signed-off-by: Steven Rostedt --- drivers/char/virtio_console.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 4df55cb..edb2ecb 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -637,6 +637,10 @@ static ssize_t port_fops_read(struct file *filp, char __user *ubuf, port = filp->private_data; + /* Port is hot-unplugged. */ + if (!port->guest_connected) + return -ENODEV; + if (!port_has_data(port)) { /* * If nothing's connected on the host just return 0 in @@ -653,7 +657,7 @@ static ssize_t port_fops_read(struct file *filp, char __user *ubuf, if (ret < 0) return ret; } - /* Port got hot-unplugged. */ + /* Port got hot-unplugged while we were waiting above. */ if (!port->guest_connected) return -ENODEV; /* -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/