From: Andrew Goodbody <andrew.goodbody@xxxxxxxxxxxxxx>
Upstream commit 21619792d1ec ("usb: usbip: Fix possible deadlocks
reported by lockdep")
Change spin_lock calls to spin_lock_irqsave to prevent
attmpted recursive lock taking in interrupt context.
This patch fixes Bug 109351
https://bugzilla.kernel.org/show_bug.cgi?id=109351
Signed-off-by: Andrew Goodbody <andrew.goodbody@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
---
drivers/usb/usbip/usbip_event.c | 5 ++-
drivers/usb/usbip/vhci_hcd.c | 88 ++++++++++++++++++++++++-----------------
drivers/usb/usbip/vhci_rx.c | 30 ++++++++------
drivers/usb/usbip/vhci_sysfs.c | 19 +++++----
drivers/usb/usbip/vhci_tx.c | 14 ++++---
5 files changed, 91 insertions(+), 65 deletions(-)
diff --git a/drivers/usb/usbip/usbip_event.c b/drivers/usb/usbip/usbip_event.c
index 64933b993d7a..2580a32bcdff 100644
--- a/drivers/usb/usbip/usbip_event.c
+++ b/drivers/usb/usbip/usbip_event.c
@@ -117,11 +117,12 @@ EXPORT_SYMBOL_GPL(usbip_event_add);
int usbip_event_happened(struct usbip_device *ud)
{
int happened = 0;
+ unsigned long flags;
- spin_lock(&ud->lock);
+ spin_lock_irqsave(&ud->lock, flags);
if (ud->event != 0)
happened = 1;
- spin_unlock(&ud->lock);
+ spin_unlock_irqrestore(&ud->lock, flags);
return happened;
}
diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c
index f9af04d7f02f..0aaa8e524afd 100644
--- a/drivers/usb/usbip/vhci_hcd.c
+++ b/drivers/usb/usbip/vhci_hcd.c
@@ -121,9 +121,11 @@ static void dump_port_status_diff(u32 prev_status, u32 new_status)
void rh_port_connect(int rhport, enum usb_device_speed speed)
{
+ unsigned long flags;
+
usbip_dbg_vhci_rh("rh_port_connect %d\n", rhport);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
the_controller->port_status[rhport] |= USB_PORT_STAT_CONNECTION
| (1 << USB_PORT_FEAT_C_CONNECTION);
@@ -139,22 +141,24 @@ void rh_port_connect(int rhport, enum usb_device_speed speed)
break;
}
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usb_hcd_poll_rh_status(vhci_to_hcd(the_controller));
}
static void rh_port_disconnect(int rhport)
{
+ unsigned long flags;
+
usbip_dbg_vhci_rh("rh_port_disconnect %d\n", rhport);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
the_controller->port_status[rhport] &= ~USB_PORT_STAT_CONNECTION;
the_controller->port_status[rhport] |=
(1 << USB_PORT_FEAT_C_CONNECTION);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usb_hcd_poll_rh_status(vhci_to_hcd(the_controller));
}
@@ -182,13 +186,14 @@ static int vhci_hub_status(struct usb_hcd *hcd, char *buf)
int retval;
int rhport;
int changed = 0;
+ unsigned long flags;
retval = DIV_ROUND_UP(VHCI_NPORTS + 1, 8);
memset(buf, 0, retval);
vhci = hcd_to_vhci(hcd);
- spin_lock(&vhci->lock);
+ spin_lock_irqsave(&vhci->lock, flags);
if (!HCD_HW_ACCESSIBLE(hcd)) {
usbip_dbg_vhci_rh("hw accessible flag not on?\n");
goto done;
@@ -209,7 +214,7 @@ static int vhci_hub_status(struct usb_hcd *hcd, char *buf)
usb_hcd_resume_root_hub(hcd);
done:
- spin_unlock(&vhci->lock);
+ spin_unlock_irqrestore(&vhci->lock, flags);
return changed ? retval : 0;
}
@@ -236,6 +241,7 @@ static int vhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
struct vhci_hcd *dum;
int retval = 0;
int rhport;
+ unsigned long flags;
u32 prev_port_status[VHCI_NPORTS];
@@ -254,7 +260,7 @@ static int vhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
dum = hcd_to_vhci(hcd);
- spin_lock(&dum->lock);
+ spin_lock_irqsave(&dum->lock, flags);
/* store old status and compare now and old later */
if (usbip_dbg_flag_vhci_rh) {
@@ -408,7 +414,7 @@ static int vhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
}
usbip_dbg_vhci_rh(" bye\n");
- spin_unlock(&dum->lock);
+ spin_unlock_irqrestore(&dum->lock, flags);
return retval;
}
@@ -431,6 +437,7 @@ static void vhci_tx_urb(struct urb *urb)
{
struct vhci_device *vdev = get_vdev(urb->dev);
struct vhci_priv *priv;
+ unsigned long flags;
if (!vdev) {
pr_err("could not get virtual device");
@@ -443,7 +450,7 @@ static void vhci_tx_urb(struct urb *urb)
return;
}
- spin_lock(&vdev->priv_lock);
+ spin_lock_irqsave(&vdev->priv_lock, flags);
priv->seqnum = atomic_inc_return(&the_controller->seqnum);
if (priv->seqnum == 0xffff)
@@ -457,7 +464,7 @@ static void vhci_tx_urb(struct urb *urb)
list_add_tail(&priv->list, &vdev->priv_tx);
wake_up(&vdev->waitq_tx);
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
}
static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
@@ -466,15 +473,16 @@ static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
struct device *dev = &urb->dev->dev;
int ret = 0;
struct vhci_device *vdev;
+ unsigned long flags;
/* patch to usb_sg_init() is in 2.5.60 */
BUG_ON(!urb->transfer_buffer && urb->transfer_buffer_length);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
if (urb->status != -EINPROGRESS) {
dev_err(dev, "URB already unlinked!, status %d\n", urb->status);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
return urb->status;
}
@@ -486,7 +494,7 @@ static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
vdev->ud.status == VDEV_ST_ERROR) {
dev_err(dev, "enqueue for inactive port %d\n", vdev->rhport);
spin_unlock(&vdev->ud.lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
return -ENODEV;
}
spin_unlock(&vdev->ud.lock);
@@ -559,14 +567,14 @@ static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
out:
vhci_tx_urb(urb);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
return 0;
no_need_xmit:
usb_hcd_unlink_urb_from_ep(hcd, urb);
no_need_unlink:
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
if (!ret)
usb_hcd_giveback_urb(vhci_to_hcd(the_controller),
urb, urb->status);
@@ -623,14 +631,15 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
struct vhci_priv *priv;
struct vhci_device *vdev;
+ unsigned long flags;
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
priv = urb->hcpriv;
if (!priv) {
/* URB was never linked! or will be soon given back by
* vhci_rx. */
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
return -EIDRM;
}
@@ -639,7 +648,7 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
ret = usb_hcd_check_unlink_urb(hcd, urb, status);
if (ret) {
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
return ret;
}
}
@@ -664,10 +673,10 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
*/
usb_hcd_unlink_urb_from_ep(hcd, urb);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
urb->status);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
} else {
/* tcp connection is alive */
@@ -679,7 +688,7 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
unlink = kzalloc(sizeof(struct vhci_unlink), GFP_ATOMIC);
if (!unlink) {
spin_unlock(&vdev->priv_lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_MALLOC);
return -ENOMEM;
}
@@ -698,7 +707,7 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
spin_unlock(&vdev->priv_lock);
}
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usbip_dbg_vhci_hc("leave\n");
return 0;
@@ -707,8 +716,9 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
{
struct vhci_unlink *unlink, *tmp;
+ unsigned long flags;
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
spin_lock(&vdev->priv_lock);
list_for_each_entry_safe(unlink, tmp, &vdev->unlink_tx, list) {
@@ -742,19 +752,19 @@ static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
list_del(&unlink->list);
spin_unlock(&vdev->priv_lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
urb->status);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
spin_lock(&vdev->priv_lock);
kfree(unlink);
}
spin_unlock(&vdev->priv_lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
}
/*
@@ -821,8 +831,9 @@ static void vhci_shutdown_connection(struct usbip_device *ud)
static void vhci_device_reset(struct usbip_device *ud)
{
struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
+ unsigned long flags;
- spin_lock(&ud->lock);
+ spin_lock_irqsave(&ud->lock, flags);
vdev->speed = 0;
vdev->devid = 0;
@@ -836,14 +847,16 @@ static void vhci_device_reset(struct usbip_device *ud)
}
ud->status = VDEV_ST_NULL;
- spin_unlock(&ud->lock);
+ spin_unlock_irqrestore(&ud->lock, flags);
}
static void vhci_device_unusable(struct usbip_device *ud)
{
- spin_lock(&ud->lock);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ud->lock, flags);
ud->status = VDEV_ST_ERROR;
- spin_unlock(&ud->lock);
+ spin_unlock_irqrestore(&ud->lock, flags);
}
static void vhci_device_init(struct vhci_device *vdev)
@@ -933,12 +946,13 @@ static int vhci_get_frame_number(struct usb_hcd *hcd)
static int vhci_bus_suspend(struct usb_hcd *hcd)
{
struct vhci_hcd *vhci = hcd_to_vhci(hcd);
+ unsigned long flags;
dev_dbg(&hcd->self.root_hub->dev, "%s\n", __func__);
- spin_lock(&vhci->lock);
+ spin_lock_irqsave(&vhci->lock, flags);
hcd->state = HC_STATE_SUSPENDED;
- spin_unlock(&vhci->lock);
+ spin_unlock_irqrestore(&vhci->lock, flags);
return 0;
}
@@ -947,15 +961,16 @@ static int vhci_bus_resume(struct usb_hcd *hcd)
{
struct vhci_hcd *vhci = hcd_to_vhci(hcd);
int rc = 0;
+ unsigned long flags;
dev_dbg(&hcd->self.root_hub->dev, "%s\n", __func__);
- spin_lock(&vhci->lock);
+ spin_lock_irqsave(&vhci->lock, flags);
if (!HCD_HW_ACCESSIBLE(hcd))
rc = -ESHUTDOWN;
else
hcd->state = HC_STATE_RUNNING;
- spin_unlock(&vhci->lock);
+ spin_unlock_irqrestore(&vhci->lock, flags);
return rc;
}
@@ -1053,17 +1068,18 @@ static int vhci_hcd_suspend(struct platform_device *pdev, pm_message_t state)
int rhport = 0;
int connected = 0;
int ret = 0;
+ unsigned long flags;
hcd = platform_get_drvdata(pdev);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
for (rhport = 0; rhport < VHCI_NPORTS; rhport++)
if (the_controller->port_status[rhport] &
USB_PORT_STAT_CONNECTION)
connected += 1;
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
if (connected > 0) {
dev_info(&pdev->dev,
diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c
index bc4eb0855314..323aa7789989 100644
--- a/drivers/usb/usbip/vhci_rx.c
+++ b/drivers/usb/usbip/vhci_rx.c
@@ -71,10 +71,11 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev,
{
struct usbip_device *ud = &vdev->ud;
struct urb *urb;
+ unsigned long flags;
- spin_lock(&vdev->priv_lock);
+ spin_lock_irqsave(&vdev->priv_lock, flags);
urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
if (!urb) {
pr_err("cannot find a urb of seqnum %u max seqnum %d\n",
@@ -103,9 +104,9 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev,
usbip_dbg_vhci_rx("now giveback urb %u\n", pdu->base.seqnum);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb, urb->status);
@@ -116,8 +117,9 @@ static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
struct usbip_header *pdu)
{
struct vhci_unlink *unlink, *tmp;
+ unsigned long flags;
- spin_lock(&vdev->priv_lock);
+ spin_lock_irqsave(&vdev->priv_lock, flags);
list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
pr_info("unlink->seqnum %lu\n", unlink->seqnum);
@@ -126,12 +128,12 @@ static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
unlink->seqnum);
list_del(&unlink->list);
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
return unlink;
}
}
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
return NULL;
}
@@ -141,6 +143,7 @@ static void vhci_recv_ret_unlink(struct vhci_device *vdev,
{
struct vhci_unlink *unlink;
struct urb *urb;
+ unsigned long flags;
usbip_dump_header(pdu);
@@ -151,9 +154,9 @@ static void vhci_recv_ret_unlink(struct vhci_device *vdev,
return;
}
- spin_lock(&vdev->priv_lock);
+ spin_lock_irqsave(&vdev->priv_lock, flags);
urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
if (!urb) {
/*
@@ -170,9 +173,9 @@ static void vhci_recv_ret_unlink(struct vhci_device *vdev,
urb->status = pdu->u.ret_unlink.status;
pr_info("urb->status %d\n", urb->status);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
urb->status);
@@ -184,10 +187,11 @@ static void vhci_recv_ret_unlink(struct vhci_device *vdev,
static int vhci_priv_tx_empty(struct vhci_device *vdev)
{
int empty = 0;
+ unsigned long flags;
- spin_lock(&vdev->priv_lock);
+ spin_lock_irqsave(&vdev->priv_lock, flags);
empty = list_empty(&vdev->priv_rx);
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
return empty;
}
diff --git a/drivers/usb/usbip/vhci_sysfs.c b/drivers/usb/usbip/vhci_sysfs.c
index 84c21c4ccf46..1c7f41a65565 100644
--- a/drivers/usb/usbip/vhci_sysfs.c
+++ b/drivers/usb/usbip/vhci_sysfs.c
@@ -32,10 +32,11 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
{
char *s = out;
int i = 0;
+ unsigned long flags;
BUG_ON(!the_controller || !out);
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
/*
* output example:
@@ -74,7 +75,7 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
spin_unlock(&vdev->ud.lock);
}
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
return out - s;
}
@@ -84,11 +85,12 @@ static DEVICE_ATTR_RO(status);
static int vhci_port_disconnect(__u32 rhport)
{
struct vhci_device *vdev;
+ unsigned long flags;
usbip_dbg_vhci_sysfs("enter\n");
/* lock */
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
vdev = port_to_vdev(rhport);
@@ -98,14 +100,14 @@ static int vhci_port_disconnect(__u32 rhport)
/* unlock */
spin_unlock(&vdev->ud.lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
return -EINVAL;
}
/* unlock */
spin_unlock(&vdev->ud.lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
usbip_event_add(&vdev->ud, VDEV_EVENT_DOWN);
@@ -181,6 +183,7 @@ static ssize_t store_attach(struct device *dev, struct device_attribute *attr,
int sockfd = 0;
__u32 rhport = 0, devid = 0, speed = 0;
int err;
+ unsigned long flags;
/*
* @rhport: port number of vhci_hcd
@@ -206,14 +209,14 @@ static ssize_t store_attach(struct device *dev, struct device_attribute *attr,
/* now need lock until setting vdev status as used */
/* begin a lock */
- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
vdev = port_to_vdev(rhport);
spin_lock(&vdev->ud.lock);
if (vdev->ud.status != VDEV_ST_NULL) {
/* end of the lock */
spin_unlock(&vdev->ud.lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
sockfd_put(socket);
@@ -232,7 +235,7 @@ static ssize_t store_attach(struct device *dev, struct device_attribute *attr,
vdev->ud.status = VDEV_ST_NOTASSIGNED;
spin_unlock(&vdev->ud.lock);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);
/* end the lock */
vdev->ud.tcp_rx = kthread_get_run(vhci_rx_loop, &vdev->ud, "vhci_rx");
diff --git a/drivers/usb/usbip/vhci_tx.c b/drivers/usb/usbip/vhci_tx.c
index 3c5796c8633a..a9a663a578b6 100644
--- a/drivers/usb/usbip/vhci_tx.c
+++ b/drivers/usb/usbip/vhci_tx.c
@@ -47,16 +47,17 @@ static void setup_cmd_submit_pdu(struct usbip_header *pdup, struct urb *urb)
static struct vhci_priv *dequeue_from_priv_tx(struct vhci_device *vdev)
{
struct vhci_priv *priv, *tmp;
+ unsigned long flags;
- spin_lock(&vdev->priv_lock);
+ spin_lock_irqsave(&vdev->priv_lock, flags);
list_for_each_entry_safe(priv, tmp, &vdev->priv_tx, list) {
list_move_tail(&priv->list, &vdev->priv_rx);
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
return priv;
}
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
return NULL;
}
@@ -137,16 +138,17 @@ static int vhci_send_cmd_submit(struct vhci_device *vdev)
static struct vhci_unlink *dequeue_from_unlink_tx(struct vhci_device *vdev)
{
struct vhci_unlink *unlink, *tmp;
+ unsigned long flags;
- spin_lock(&vdev->priv_lock);
+ spin_lock_irqsave(&vdev->priv_lock, flags);
list_for_each_entry_safe(unlink, tmp, &vdev->unlink_tx, list) {
list_move_tail(&unlink->list, &vdev->unlink_rx);
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
return unlink;
}
- spin_unlock(&vdev->priv_lock);
+ spin_unlock_irqrestore(&vdev->priv_lock, flags);
return NULL;
}
--
2.14.1
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
