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Commit a78012ad authored by Mike Lockwood's avatar Mike Lockwood
Browse files

adb: avoid potential race conditions in detecting device disconnects 



I am hoping this will fix b/2767449 and b/2752393

Change-Id: I230310d37f50eb2a2e1bad31e374427fd44393a5
Signed-off-by: default avatarMike Lockwood <lockwood@android.com>
parent c5947806

adb/usb_linux.c

+33 −32
Original line number Diff line number Diff line
@@ -81,13 +81,41 @@ static int known_device(const char *dev_name) 


static void kick_disconnected_device(const char *devname, void *client_data)

{

    usb_handle *usb;

    usb_handle *h;



    adb_mutex_lock(&usb_lock);

    /* kick the device if it is in our list */

    for (usb = handle_list.next; usb != &handle_list; usb = usb->next) {

        if (!strcmp(devname, usb_device_get_name(usb->device)))

            usb_kick(usb);

    for (h = handle_list.next; h != &handle_list; h = h->next) {

        if (!strcmp(devname, usb_device_get_name(h->device))) {

            D("[ kicking %p (fd = %s) ]\n", h, usb_device_get_name(h->device));

            adb_mutex_lock(&h->lock);

            if(h->dead == 0) {

                h->dead = 1;



                if (usb_device_is_writeable(h->device)) {

                    /* HACK ALERT!

                    ** Sometimes we get stuck in ioctl(USBDEVFS_REAPURB).

                    ** This is a workaround for that problem.

                    */

                    if (h->reaper_thread) {

                        pthread_kill(h->reaper_thread, SIGALRM);

                    }



                    /* cancel any pending transactions

                    ** these will quietly fail if the txns are not active,

                    ** but this ensures that a reader blocked on REAPURB

                    ** will get unblocked

                    */

                    usb_endpoint_cancel(h->ep_in);

                    usb_endpoint_cancel(h->ep_out);

                    adb_cond_broadcast(&h->notify_in);

                    adb_cond_broadcast(&h->notify_out);

                } else {

                    unregister_usb_transport(h);

                }

            }

            adb_mutex_unlock(&h->lock);

        }

    }

    adb_mutex_unlock(&usb_lock);
@@ -405,34 +433,7 @@ int usb_read(usb_handle *h, void *_data, int len) 


void usb_kick(usb_handle *h)

{

    D("[ kicking %p (fd = %s) ]\n", h, usb_device_get_name(h->device));

    adb_mutex_lock(&h->lock);

    if(h->dead == 0) {

        h->dead = 1;



        if (usb_device_is_writeable(h->device)) {

            /* HACK ALERT!

            ** Sometimes we get stuck in ioctl(USBDEVFS_REAPURB).

            ** This is a workaround for that problem.

            */

            if (h->reaper_thread) {

                pthread_kill(h->reaper_thread, SIGALRM);

            }



            /* cancel any pending transactions

            ** these will quietly fail if the txns are not active,

            ** but this ensures that a reader blocked on REAPURB

            ** will get unblocked

            */

            usb_endpoint_cancel(h->ep_in);

            usb_endpoint_cancel(h->ep_out);

            adb_cond_broadcast(&h->notify_in);

            adb_cond_broadcast(&h->notify_out);

        } else {

            unregister_usb_transport(h);

        }

    }

    adb_mutex_unlock(&h->lock);

    // do nothing here. we kick in kick_disconnected_devices instead.

}



int usb_close(usb_handle *h)