5 files changed, 59 insertions, 11 deletions

diff --git a/drivers/usb/mon/mon_dma.c b/drivers/usb/mon/mon_dma.c
index 0a1367b760a0..ddcfc01e77a0 100644
--- a/drivers/usb/mon/mon_dma.c
+++ b/drivers/usb/mon/mon_dma.c
@@ -13,7 +13,10 @@
 #include <linux/usb.h>	/* Only needed for declarations in usb_mon.h */
 #include "usb_mon.h"
 
-#ifdef __i386__		/* CONFIG_ARCH_I386 does not exit */
+/*
+ * PC-compatibles, are, fortunately, sufficiently cache-coherent for this.
+ */
+#if defined(__i386__) || defined(__x86_64__) /* CONFIG_ARCH_I386 doesn't exit */
 #define MON_HAS_UNMAP 1
 
 #define phys_to_page(phys)	pfn_to_page((phys) >> PAGE_SHIFT)
diff --git a/drivers/usb/mon/mon_main.c b/drivers/usb/mon/mon_main.c
index 6ecc27302211..275a66f83058 100644
--- a/drivers/usb/mon/mon_main.c
+++ b/drivers/usb/mon/mon_main.c
@@ -97,6 +97,7 @@ static void mon_submit(struct usb_bus *ubus, struct urb *urb)
 	if (mbus->nreaders == 0)
 		goto out_locked;
 
+	mbus->cnt_events++;
 	list_for_each (pos, &mbus->r_list) {
 		r = list_entry(pos, struct mon_reader, r_link);
 		r->rnf_submit(r->r_data, urb);
@@ -113,20 +114,32 @@ out_unlocked:
 
 /*
  */
-static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int err)
+static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
 {
 	struct mon_bus *mbus;
+	unsigned long flags;
+	struct list_head *pos;
+	struct mon_reader *r;
 
 	mbus = ubus->mon_bus;
 	if (mbus == NULL)
 		goto out_unlocked;
 
-	/*
-	 * XXX Capture the error code and the 'E' event.
-	 */
+	spin_lock_irqsave(&mbus->lock, flags);
+	if (mbus->nreaders == 0)
+		goto out_locked;
 
+	mbus->cnt_events++;
+	list_for_each (pos, &mbus->r_list) {
+		r = list_entry(pos, struct mon_reader, r_link);
+		r->rnf_error(r->r_data, urb, error);
+	}
+
+	spin_unlock_irqrestore(&mbus->lock, flags);
 	return;
 
+out_locked:
+	spin_unlock_irqrestore(&mbus->lock, flags);
 out_unlocked:
 	return;
 }
@@ -152,6 +165,7 @@ static void mon_complete(struct usb_bus *ubus, struct urb *urb)
 	}
 
 	spin_lock_irqsave(&mbus->lock, flags);
+	mbus->cnt_events++;
 	list_for_each (pos, &mbus->r_list) {
 		r = list_entry(pos, struct mon_reader, r_link);
 		r->rnf_complete(r->r_data, urb);
@@ -163,7 +177,6 @@ static void mon_complete(struct usb_bus *ubus, struct urb *urb)
 
 /*
  * Stop monitoring.
- * Obviously this must be well locked, so no need to play with mb's.
  */
 static void mon_stop(struct mon_bus *mbus)
 {
diff --git a/drivers/usb/mon/mon_stat.c b/drivers/usb/mon/mon_stat.c
index 6e4b165d070a..1fe01d994a79 100644
--- a/drivers/usb/mon/mon_stat.c
+++ b/drivers/usb/mon/mon_stat.c
@@ -31,8 +31,8 @@ static int mon_stat_open(struct inode *inode, struct file *file)
 	mbus = inode->u.generic_ip;
 
 	sp->slen = snprintf(sp->str, STAT_BUF_SIZE,
-	    "nreaders %d text_lost %u\n",
-	    mbus->nreaders, mbus->cnt_text_lost);
+	    "nreaders %d events %u text_lost %u\n",
+	    mbus->nreaders, mbus->cnt_events, mbus->cnt_text_lost);
 
 	file->private_data = sp;
 	return 0;
diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
index ac043ec2b8dc..e02c1a30c4cd 100644
--- a/drivers/usb/mon/mon_text.c
+++ b/drivers/usb/mon/mon_text.c
@@ -26,10 +26,13 @@
 
 /*
  * This limit exists to prevent OOMs when the user process stops reading.
+ * If usbmon were available to unprivileged processes, it might be open
+ * to a local DoS. But we have to keep to root in order to prevent
+ * password sniffing from HID devices.
  */
-#define EVENT_MAX  25
+#define EVENT_MAX  (2*PAGE_SIZE / sizeof(struct mon_event_text))
 
-#define PRINTF_DFL  130
+#define PRINTF_DFL  160
 
 struct mon_event_text {
 	struct list_head e_link;
@@ -111,7 +114,7 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
 	 * number of corner cases, but it seems that the following is
 	 * more or less safe.
 	 *
-	 * We do not even try to look transfer_buffer, because it can
+	 * We do not even try to look at transfer_buffer, because it can
 	 * contain non-NULL garbage in case the upper level promised to
 	 * set DMA for the HCD.
 	 */
@@ -179,6 +182,32 @@ static void mon_text_complete(void *data, struct urb *urb)
 	mon_text_event(rp, urb, 'C');
 }
 
+static void mon_text_error(void *data, struct urb *urb, int error)
+{
+	struct mon_reader_text *rp = data;
+	struct mon_event_text *ep;
+
+	if (rp->nevents >= EVENT_MAX ||
+	    (ep = kmem_cache_alloc(rp->e_slab, SLAB_ATOMIC)) == NULL) {
+		rp->r.m_bus->cnt_text_lost++;
+		return;
+	}
+
+	ep->type = 'E';
+	ep->pipe = urb->pipe;
+	ep->id = (unsigned long) urb;
+	ep->tstamp = 0;
+	ep->length = 0;
+	ep->status = error;
+
+	ep->setup_flag = '-';
+	ep->data_flag = 'E';
+
+	rp->nevents++;
+	list_add_tail(&ep->e_link, &rp->e_list);
+	wake_up(&rp->wait);
+}
+
 /*
  * Fetch next event from the circular buffer.
  */
@@ -232,6 +261,7 @@ static int mon_text_open(struct inode *inode, struct file *file)
 	rp->r.m_bus = mbus;
 	rp->r.r_data = rp;
 	rp->r.rnf_submit = mon_text_submit;
+	rp->r.rnf_error = mon_text_error;
 	rp->r.rnf_complete = mon_text_complete;
 
 	snprintf(rp->slab_name, SLAB_NAME_SZ, "mon%dt_%lx", ubus->busnum,
diff --git a/drivers/usb/mon/usb_mon.h b/drivers/usb/mon/usb_mon.h
index 8e0613c350cc..33678c24ebee 100644
--- a/drivers/usb/mon/usb_mon.h
+++ b/drivers/usb/mon/usb_mon.h
@@ -27,6 +27,7 @@ struct mon_bus {
 	struct kref ref;		/* Under mon_lock */
 
 	/* Stats */
+	unsigned int cnt_events;
 	unsigned int cnt_text_lost;
 };
 
@@ -39,6 +40,7 @@ struct mon_reader {
 	void *r_data;		/* Use container_of instead? */
 
 	void (*rnf_submit)(void *data, struct urb *urb);
+	void (*rnf_error)(void *data, struct urb *urb, int error);
 	void (*rnf_complete)(void *data, struct urb *urb);
 };