From 36e59e0d70d6150e7a2155c54612ea875e88ce8d Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Fri, 20 Mar 2015 09:24:24 +0100 Subject: cdc-acm: fix race between callback and unthrottle Abn URB may be may marked free only after the buffer has been processed or there is a small window during which it could be submitted on another CPU and overwrite an unprocessed buffer Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'drivers/usb/class/cdc-acm.c') diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 683617714e7c..58241ec1e91d 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -417,25 +417,33 @@ static void acm_read_bulk_callback(struct urb *urb) struct acm_rb *rb = urb->context; struct acm *acm = rb->instance; unsigned long flags; + int status = urb->status; dev_vdbg(&acm->data->dev, "%s - urb %d, len %d\n", __func__, rb->index, urb->actual_length); - set_bit(rb->index, &acm->read_urbs_free); if (!acm->dev) { + set_bit(rb->index, &acm->read_urbs_free); dev_dbg(&acm->data->dev, "%s - disconnected\n", __func__); return; } if (urb->status) { + set_bit(rb->index, &acm->read_urbs_free); dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n", - __func__, urb->status); + __func__, status); return; } usb_mark_last_busy(acm->dev); acm_process_read_urb(acm, urb); + /* + * Unthrottle may run on another CPU which needs to see events + * in the same order. Submission has an implict barrier + */ + smp_mb__before_atomic(); + set_bit(rb->index, &acm->read_urbs_free); /* throttle device if requested by tty */ spin_lock_irqsave(&acm->read_lock, flags); -- cgit v1.2.3 From 6c8074e90c7350f5e38caf1e8d73e98df4115403 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Fri, 20 Mar 2015 11:25:17 +0100 Subject: cdc-acm: surpress misleading message During the entry intro suspend a misleading message can be printed. Surpress it by checking the specific error. Signed-off-by: Oliver Neukum 0 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/usb/class/cdc-acm.c') diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 58241ec1e91d..43cb05863fac 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -360,7 +360,7 @@ static void acm_ctrl_irq(struct urb *urb) } exit: retval = usb_submit_urb(urb, GFP_ATOMIC); - if (retval) + if (retval && retval != -EPERM) dev_err(&acm->control->dev, "%s - usb_submit_urb failed: %d\n", __func__, retval); } -- cgit v1.2.3 From 4132cd02db180d018325e26bd145a509a14fcd6b Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Fri, 20 Mar 2015 11:41:06 +0100 Subject: cdc-acm: convert to not directly using urb->status A step on the road to passing status as a parameter Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/usb/class/cdc-acm.c') diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 43cb05863fac..3e15add665e2 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -428,7 +428,7 @@ static void acm_read_bulk_callback(struct urb *urb) return; } - if (urb->status) { + if (status) { set_bit(rb->index, &acm->read_urbs_free); dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n", __func__, status); @@ -462,13 +462,14 @@ static void acm_write_bulk(struct urb *urb) struct acm_wb *wb = urb->context; struct acm *acm = wb->instance; unsigned long flags; + int status = urb->status; - if (urb->status || (urb->actual_length != urb->transfer_buffer_length)) + if (status || (urb->actual_length != urb->transfer_buffer_length)) dev_vdbg(&acm->data->dev, "%s - len %d/%d, status %d\n", __func__, urb->actual_length, urb->transfer_buffer_length, - urb->status); + status); spin_lock_irqsave(&acm->write_lock, flags); acm_write_done(acm, wb); -- cgit v1.2.3