This is a note to let you know that I've just added the patch titled
usb: gadget: f_ecm: Use atomic_t to track in-flight request
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the usb-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From d710562e01c48d59be3f60d58b7a85958b39aeda Mon Sep 17 00:00:00 2001
From: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
Date: Thu, 9 Jan 2020 13:17:22 +0000
Subject: usb: gadget: f_ecm: Use atomic_t to track in-flight request
Currently ecm->notify_req is used to flag when a request is in-flight.
ecm->notify_req is set to NULL and when a request completes it is
subsequently reset.
This is fundamentally buggy in that the unbind logic of the ECM driver will
unconditionally free ecm->notify_req leading to a NULL pointer dereference.
Fixes: da741b8c56d6 ("usb ethernet gadget: split CDC Ethernet function")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_ecm.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_ecm.c b/drivers/usb/gadget/function/f_ecm.c
index 460d5d7c984f..7f5cf488b2b1 100644
--- a/drivers/usb/gadget/function/f_ecm.c
+++ b/drivers/usb/gadget/function/f_ecm.c
@@ -52,6 +52,7 @@ struct f_ecm {
struct usb_ep *notify;
struct usb_request *notify_req;
u8 notify_state;
+ atomic_t notify_count;
bool is_open;
/* FIXME is_open needs some irq-ish locking
@@ -380,7 +381,7 @@ static void ecm_do_notify(struct f_ecm *ecm)
int status;
/* notification already in flight? */
- if (!req)
+ if (atomic_read(&ecm->notify_count))
return;
event = req->buf;
@@ -420,10 +421,10 @@ static void ecm_do_notify(struct f_ecm *ecm)
event->bmRequestType = 0xA1;
event->wIndex = cpu_to_le16(ecm->ctrl_id);
- ecm->notify_req = NULL;
+ atomic_inc(&ecm->notify_count);
status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC);
if (status < 0) {
- ecm->notify_req = req;
+ atomic_dec(&ecm->notify_count);
DBG(cdev, "notify --> %d\n", status);
}
}
@@ -448,17 +449,19 @@ static void ecm_notify_complete(struct usb_ep *ep, struct usb_request *req)
switch (req->status) {
case 0:
/* no fault */
+ atomic_dec(&ecm->notify_count);
break;
case -ECONNRESET:
case -ESHUTDOWN:
+ atomic_set(&ecm->notify_count, 0);
ecm->notify_state = ECM_NOTIFY_NONE;
break;
default:
DBG(cdev, "event %02x --> %d\n",
event->bNotificationType, req->status);
+ atomic_dec(&ecm->notify_count);
break;
}
- ecm->notify_req = req;
ecm_do_notify(ecm);
}
@@ -907,6 +910,11 @@ static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
usb_free_all_descriptors(f);
+ if (atomic_read(&ecm->notify_count)) {
+ usb_ep_dequeue(ecm->notify, ecm->notify_req);
+ atomic_set(&ecm->notify_count, 0);
+ }
+
kfree(ecm->notify_req->buf);
usb_ep_free_request(ecm->notify, ecm->notify_req);
}
--
2.24.1
