This is a note to let you know that I've just added the patch titled usb: cdc-acm: handle unlinked urb in acm read callback to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-cdc-acm-handle-unlinked-urb-in-acm-read-callback.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 19454462acb1bdef80542061bdc9b410e4ed1ff6 Mon Sep 17 00:00:00 2001 From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> Date: Wed, 30 Dec 2015 12:59:08 +0800 Subject: usb: cdc-acm: handle unlinked urb in acm read callback From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> commit 19454462acb1bdef80542061bdc9b410e4ed1ff6 upstream. In current acm driver, the bulk-in callback function ignores the URBs unlinked in usb core. This causes unexpected data loss in some cases. For example, runtime suspend entry will unlinked all urbs and set urb->status to -ENOENT even those urbs might have data not processed yet. Hence, data loss occurs. This patch lets bulk-in callback function handle unlinked urbs to avoid data loss. Signed-off-by: Tang Jian Qiang <jianqiang.tang@xxxxxxxxx> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> Acked-by: Oliver Neukum <oneukum@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/class/cdc-acm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -428,7 +428,8 @@ static void acm_read_bulk_callback(struc set_bit(rb->index, &acm->read_urbs_free); dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n", __func__, status); - return; + if ((status != -ENOENT) || (urb->actual_length == 0)) + return; } usb_mark_last_busy(acm->dev); Patches currently in stable-queue which might be from baolu.lu@xxxxxxxxxxxxxxx are queue-4.4/usb-xhci-handle-both-ssic-ports-in-pme-stuck-quirk.patch queue-4.4/usb-cdc-acm-send-zero-packet-for-intel-7260-modem.patch queue-4.4/usb-xhci-apply-xhci_pme_stuck_quirk-to-intel-broxton-m-platforms.patch queue-4.4/usb-cdc-acm-handle-unlinked-urb-in-acm-read-callback.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html