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Resolve a deadlock setting the USB configuration index from userspace

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on USB HUBs by moving the code into the USB explore threads. The
deadlock happens because child devices of the USB HUB don't have the
expected reference count when called from outside the explore
thread. Only the HUB device itself, which the IOCTL interface locks,
gets the correct reference count.

MFC after:	3 days
This commit is contained in:
hselasky 2014-06-08 20:10:29 +00:00
parent 6106e186e6
commit 35c04fd76f
7 changed files with 133 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
sys/dev/usb/controller/usb_controller.c
View File

@ -367,7 +367,13 @@ usb_bus_explore(struct usb_proc_msg *pm)
if (bus->no_explore != 0)
return;
if (udev && udev->hub) {
if (udev != NULL) {
USB_BUS_UNLOCK(bus);
uhub_explore_handle_re_enumerate(udev);
USB_BUS_LOCK(bus);
}
if (udev != NULL && udev->hub != NULL) {
if (bus->do_probe) {
bus->do_probe = 0;

11
sys/dev/usb/usb_dev.c
View File

@ -1116,9 +1116,14 @@ usb_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int fflag, struct thread*
usb_pause_mtx(NULL, hz / 128);
if (usb_ref_device(cpd, &refs, 1 /* need uref */)) {
err = ENXIO;
goto done;
while (usb_ref_device(cpd, &refs, 1 /* need uref */)) {
if (usb_ref_device(cpd, &refs, 0)) {
/* device no longer exits */
err = ENXIO;
goto done;
}
usb_unref_device(cpd, &refs);
usb_pause_mtx(NULL, hz / 128);
}
}

2
sys/dev/usb/usb_device.h
View File

@ -228,6 +228,7 @@ struct usb_device {
uint8_t address; /* device addess */
uint8_t device_index; /* device index in "bus->devices" */
uint8_t controller_slot_id; /* controller specific value */
uint8_t next_config_index; /* used by USB_RE_ENUM_SET_CONFIG */
uint8_t curr_config_index; /* current configuration index */
uint8_t curr_config_no; /* current configuration number */
uint8_t depth; /* distance from root HUB */
@ -241,6 +242,7 @@ struct usb_device {
#define USB_RE_ENUM_DONE 0
#define USB_RE_ENUM_START 1
#define USB_RE_ENUM_PWR_OFF 2
#define USB_RE_ENUM_SET_CONFIG 3
uint8_t ifaces_max; /* number of interfaces present */
uint8_t endpoints_max; /* number of endpoints present */

20
sys/dev/usb/usb_generic.c
View File

@ -616,24 +616,17 @@ ugen_set_config(struct usb_fifo *f, uint8_t index)
/* not possible in device side mode */
return (ENOTTY);
}
if (f->udev->curr_config_index == index) {
/* no change needed */
return (0);
}
/* make sure all FIFO's are gone */
/* else there can be a deadlock */
if (ugen_fs_uninit(f)) {
/* ignore any errors */
DPRINTFN(6, "no FIFOs\n");
}
/* change setting - will free generic FIFOs, if any */
if (usbd_set_config_index(f->udev, index)) {
if (usbd_start_set_config(f->udev, index) != 0)
return (EIO);
}
/* probe and attach */
if (usb_probe_and_attach(f->udev, USB_IFACE_INDEX_ANY)) {
return (EIO);
}
return (0);
}
@ -970,11 +963,6 @@ ugen_re_enumerate(struct usb_fifo *f)
DPRINTFN(6, "device mode\n");
return (ENOTTY);
}
if (udev->parent_hub == NULL) {
/* the root HUB cannot be re-enumerated */
DPRINTFN(6, "cannot reset root HUB\n");
return (EINVAL);
}
/* make sure all FIFO's are gone */
/* else there can be a deadlock */
if (ugen_fs_uninit(f)) {

162
sys/dev/usb/usb_hub.c
View File

@ -427,6 +427,86 @@ done:
return (retval);
}
void
uhub_explore_handle_re_enumerate(struct usb_device *child)
{
uint8_t do_unlock;
usb_error_t err;
/* check if device should be re-enumerated */
if (child->flags.usb_mode != USB_MODE_HOST)
return;
do_unlock = usbd_enum_lock(child);
switch (child->re_enumerate_wait) {
case USB_RE_ENUM_START:
err = usbd_set_config_index(child,
USB_UNCONFIG_INDEX);
if (err != 0) {
DPRINTF("Unconfigure failed: %s: Ignored.\n",
usbd_errstr(err));
}
if (child->parent_hub == NULL) {
/* the root HUB cannot be re-enumerated */
DPRINTFN(6, "cannot reset root HUB\n");
err = 0;
} else {
err = usbd_req_re_enumerate(child, NULL);
}
if (err == 0)
err = usbd_set_config_index(child, 0);
if (err == 0) {
err = usb_probe_and_attach(child,
USB_IFACE_INDEX_ANY);
}
child->re_enumerate_wait = USB_RE_ENUM_DONE;
break;
case USB_RE_ENUM_PWR_OFF:
/* get the device unconfigured */
err = usbd_set_config_index(child,
USB_UNCONFIG_INDEX);
if (err) {
DPRINTFN(0, "Could not unconfigure "
"device (ignored)\n");
}
if (child->parent_hub == NULL) {
/* the root HUB cannot be re-enumerated */
DPRINTFN(6, "cannot set port feature\n");
err = 0;
} else {
/* clear port enable */
err = usbd_req_clear_port_feature(child->parent_hub,
NULL, child->port_no, UHF_PORT_ENABLE);
if (err) {
DPRINTFN(0, "Could not disable port "
"(ignored)\n");
}
}
child->re_enumerate_wait = USB_RE_ENUM_DONE;
break;
case USB_RE_ENUM_SET_CONFIG:
err = usbd_set_config_index(child,
child->next_config_index);
if (err != 0) {
DPRINTF("Configure failed: %s: Ignored.\n",
usbd_errstr(err));
} else {
err = usb_probe_and_attach(child,
USB_IFACE_INDEX_ANY);
}
child->re_enumerate_wait = USB_RE_ENUM_DONE;
break;
default:
child->re_enumerate_wait = USB_RE_ENUM_DONE;
break;
}
if (do_unlock)
usbd_enum_unlock(child);
}
/*------------------------------------------------------------------------*
* uhub_explore_sub - subroutine
*
@ -455,59 +535,7 @@ uhub_explore_sub(struct uhub_softc *sc, struct usb_port *up)
goto done;
}
/* check if device should be re-enumerated */
if (child->flags.usb_mode == USB_MODE_HOST) {
uint8_t do_unlock;
do_unlock = usbd_enum_lock(child);
switch (child->re_enumerate_wait) {
case USB_RE_ENUM_START:
err = usbd_set_config_index(child,
USB_UNCONFIG_INDEX);
if (err != 0) {
DPRINTF("Unconfigure failed: "
"%s: Ignored.\n",
usbd_errstr(err));
}
err = usbd_req_re_enumerate(child, NULL);
if (err == 0)
err = usbd_set_config_index(child, 0);
if (err == 0) {
err = usb_probe_and_attach(child,
USB_IFACE_INDEX_ANY);
}
child->re_enumerate_wait = USB_RE_ENUM_DONE;
err = 0;
break;
case USB_RE_ENUM_PWR_OFF:
/* get the device unconfigured */
err = usbd_set_config_index(child,
USB_UNCONFIG_INDEX);
if (err) {
DPRINTFN(0, "Could not unconfigure "
"device (ignored)\n");
}
/* clear port enable */
err = usbd_req_clear_port_feature(child->parent_hub,
NULL, child->port_no, UHF_PORT_ENABLE);
if (err) {
DPRINTFN(0, "Could not disable port "
"(ignored)\n");
}
child->re_enumerate_wait = USB_RE_ENUM_DONE;
err = 0;
break;
default:
child->re_enumerate_wait = USB_RE_ENUM_DONE;
break;
}
if (do_unlock)
usbd_enum_unlock(child);
}
uhub_explore_handle_re_enumerate(child);
/* check if probe and attach should be done */
@ -2799,3 +2827,31 @@ usbd_start_re_enumerate(struct usb_device *udev)
usb_needs_explore(udev->bus, 0);
}
}
/*-----------------------------------------------------------------------*
* usbd_start_set_config
*
* This function starts setting a USB configuration. This function
* does not need to be called BUS-locked. This function does not wait
* until the set USB configuratino is completed.
*------------------------------------------------------------------------*/
usb_error_t
usbd_start_set_config(struct usb_device *udev, uint8_t index)
{
if (udev->re_enumerate_wait == USB_RE_ENUM_DONE) {
if (udev->curr_config_index == index) {
/* no change needed */
return (0);
}
udev->next_config_index = index;
udev->re_enumerate_wait = USB_RE_ENUM_SET_CONFIG;
usb_needs_explore(udev->bus, 0);
return (0);
} else if (udev->re_enumerate_wait == USB_RE_ENUM_SET_CONFIG) {
if (udev->next_config_index == index) {
/* no change needed */
return (0);
}
}
return (USB_ERR_PENDING_REQUESTS);
}

1
sys/dev/usb/usb_hub.h
View File

@ -75,5 +75,6 @@ void usb_bus_power_update(struct usb_bus *bus);
void usb_bus_powerd(struct usb_bus *bus);
void uhub_root_intr(struct usb_bus *, const uint8_t *, uint8_t);
usb_error_t uhub_query_info(struct usb_device *, uint8_t *, uint8_t *);
void uhub_explore_handle_re_enumerate(struct usb_device *);
#endif /* _USB_HUB_H_ */

2
sys/dev/usb/usbdi.h
View File

@ -586,6 +586,8 @@ void usbd_m_copy_in(struct usb_page_cache *cache, usb_frlength_t dst_offset,
void usbd_frame_zero(struct usb_page_cache *cache, usb_frlength_t offset,
usb_frlength_t len);
void usbd_start_re_enumerate(struct usb_device *udev);
usb_error_t
usbd_start_set_config(struct usb_device *, uint8_t);
int usb_fifo_attach(struct usb_device *udev, void *priv_sc,
struct mtx *priv_mtx, struct usb_fifo_methods *pm,