diff options
| author | Bryan O'Donoghue <bryan.odonoghue@linaro.org> | 2020-01-09 16:17:22 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-15 00:32:08 +0300 |
| commit | 7d0c0dfe866736e221ce1773a6b45b06af945e9b (patch) | |
| tree | 27647d4aaa0b1876b22b94b6739d3ff389454882 /drivers | |
| parent | 51f94eb089ee1aed6a846925265bc645dc30a99f (diff) | |
| download | linux-7d0c0dfe866736e221ce1773a6b45b06af945e9b.tar.xz | |
usb: gadget: f_ecm: Use atomic_t to track in-flight request
commit d710562e01c48d59be3f60d58b7a85958b39aeda upstream.
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@vger.kernel.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/gadget/function/f_ecm.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/usb/gadget/function/f_ecm.c b/drivers/usb/gadget/function/f_ecm.c index dc99ed94f03d..8e3e44382785 100644 --- a/drivers/usb/gadget/function/f_ecm.c +++ b/drivers/usb/gadget/function/f_ecm.c @@ -56,6 +56,7 @@ 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 @@ -384,7 +385,7 @@ 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; @@ -424,10 +425,10 @@ 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); } } @@ -452,17 +453,19 @@ 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); } @@ -909,6 +912,11 @@ 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); } |