This is a note to let you know that I've just added the patch titled
USB: Remove races in devio.c
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-remove-races-in-devio.c.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 4e09dcf20f7b5358615514c2ec8584b248ab8874 Mon Sep 17 00:00:00 2001
From: Huajun Li <[email protected]>
Date: Fri, 18 May 2012 20:12:51 +0800
Subject: USB: Remove races in devio.c
From: Huajun Li <[email protected]>
commit 4e09dcf20f7b5358615514c2ec8584b248ab8874 upstream.
There exist races in devio.c, below is one case,
and there are similar races in destroy_async()
and proc_unlinkurb(). Remove these races.
cancel_bulk_urbs() async_completed()
------------------- -----------------------
spin_unlock(&ps->lock);
list_move_tail(&as->asynclist,
&ps->async_completed);
wake_up(&ps->wait);
Lead to free_async() be triggered,
then urb and 'as' will be freed.
usb_unlink_urb(as->urb);
===> refer to the freed 'as'
Signed-off-by: Huajun Li <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: Oncaphillis <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/core/devio.c | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -333,17 +333,14 @@ static struct async *async_getcompleted(
static struct async *async_getpending(struct dev_state *ps,
void __user *userurb)
{
- unsigned long flags;
struct async *as;
- spin_lock_irqsave(&ps->lock, flags);
list_for_each_entry(as, &ps->async_pending, asynclist)
if (as->userurb == userurb) {
list_del_init(&as->asynclist);
- spin_unlock_irqrestore(&ps->lock, flags);
return as;
}
- spin_unlock_irqrestore(&ps->lock, flags);
+
return NULL;
}
@@ -398,6 +395,7 @@ static void cancel_bulk_urbs(struct dev_
__releases(ps->lock)
__acquires(ps->lock)
{
+ struct urb *urb;
struct async *as;
/* Mark all the pending URBs that match bulk_addr, up to but not
@@ -420,8 +418,11 @@ __acquires(ps->lock)
list_for_each_entry(as, &ps->async_pending, asynclist) {
if (as->bulk_status == AS_UNLINK) {
as->bulk_status = 0; /* Only once */
+ urb = as->urb;
+ usb_get_urb(urb);
spin_unlock(&ps->lock); /* Allow completions */
- usb_unlink_urb(as->urb);
+ usb_unlink_urb(urb);
+ usb_put_urb(urb);
spin_lock(&ps->lock);
goto rescan;
}
@@ -472,6 +473,7 @@ static void async_completed(struct urb *
static void destroy_async(struct dev_state *ps, struct list_head *list)
{
+ struct urb *urb;
struct async *as;
unsigned long flags;
@@ -479,10 +481,13 @@ static void destroy_async(struct dev_sta
while (!list_empty(list)) {
as = list_entry(list->next, struct async, asynclist);
list_del_init(&as->asynclist);
+ urb = as->urb;
+ usb_get_urb(urb);
/* drop the spinlock so the completion handler can run */
spin_unlock_irqrestore(&ps->lock, flags);
- usb_kill_urb(as->urb);
+ usb_kill_urb(urb);
+ usb_put_urb(urb);
spin_lock_irqsave(&ps->lock, flags);
}
spin_unlock_irqrestore(&ps->lock, flags);
@@ -1410,12 +1415,24 @@ static int proc_submiturb(struct dev_sta
static int proc_unlinkurb(struct dev_state *ps, void __user *arg)
{
+ struct urb *urb;
struct async *as;
+ unsigned long flags;
+ spin_lock_irqsave(&ps->lock, flags);
as = async_getpending(ps, arg);
- if (!as)
+ if (!as) {
+ spin_unlock_irqrestore(&ps->lock, flags);
return -EINVAL;
- usb_kill_urb(as->urb);
+ }
+
+ urb = as->urb;
+ usb_get_urb(urb);
+ spin_unlock_irqrestore(&ps->lock, flags);
+
+ usb_kill_urb(urb);
+ usb_put_urb(urb);
+
return 0;
}
Patches currently in stable-queue which might be from [email protected]
are
queue-3.3/usb-remove-races-in-devio.c.patch
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