From: Anirudh Rayabharam <mail@anirudhrb.com>
To: Valentina Manea <valentina.manea.m@gmail.com>,
Shuah Khan <shuah@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel-mentees@lists.linuxfoundation.org,
Anirudh Rayabharam <mail@anirudhrb.com>,
syzbot+74d6ef051d3d2eacf428@syzkaller.appspotmail.com,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] usbip: give back URBs for unsent unlink requests during cleanup
Date: Fri, 6 Aug 2021 22:10:14 +0530 [thread overview]
Message-ID: <20210806164015.25263-1-mail@anirudhrb.com> (raw)
In vhci_device_unlink_cleanup(), the URBs for unsent unlink requests are
not given back. This sometimes causes usb_kill_urb to wait indefinitely
for that urb to be given back. syzbot has reported a hung task issue [1]
for this.
To fix this, give back the urbs corresponding to unsent unlink requests
(unlink_tx list) similar to how urbs corresponding to unanswered unlink
requests (unlink_rx list) are given back. Since the code is almost the
same, extract it into a new function and call it for both unlink_rx and
unlink_tx lists.
[1]: https://syzkaller.appspot.com/bug?id=08f12df95ae7da69814e64eb5515d5a85ed06b76
Reported-by: syzbot+74d6ef051d3d2eacf428@syzkaller.appspotmail.com
Tested-by: syzbot+74d6ef051d3d2eacf428@syzkaller.appspotmail.com
Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
---
drivers/usb/usbip/vhci_hcd.c | 47 ++++++++++++++++++++++++++----------
1 file changed, 34 insertions(+), 13 deletions(-)
diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c
index 4ba6bcdaa8e9..45f98aa12895 100644
--- a/drivers/usb/usbip/vhci_hcd.c
+++ b/drivers/usb/usbip/vhci_hcd.c
@@ -945,7 +945,8 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
return 0;
}
-static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
+static void __vhci_cleanup_unlink_list(struct vhci_device *vdev,
+ struct list_head *unlink_list)
{
struct vhci_hcd *vhci_hcd = vdev_to_vhci_hcd(vdev);
struct usb_hcd *hcd = vhci_hcd_to_hcd(vhci_hcd);
@@ -953,23 +954,25 @@ static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
struct vhci_unlink *unlink, *tmp;
unsigned long flags;
+ if (unlink_list != &vdev->unlink_tx
+ && unlink_list != &vdev->unlink_rx) {
+ pr_err("Invalid list passed to __vhci_cleanup_unlink_list\n");
+ BUG();
+ return;
+ }
+
spin_lock_irqsave(&vhci->lock, flags);
spin_lock(&vdev->priv_lock);
- list_for_each_entry_safe(unlink, tmp, &vdev->unlink_tx, list) {
- pr_info("unlink cleanup tx %lu\n", unlink->unlink_seqnum);
- list_del(&unlink->list);
- kfree(unlink);
- }
-
- while (!list_empty(&vdev->unlink_rx)) {
+ list_for_each_entry_safe(unlink, tmp, unlink_list, list) {
struct urb *urb;
- unlink = list_first_entry(&vdev->unlink_rx, struct vhci_unlink,
- list);
-
- /* give back URB of unanswered unlink request */
- pr_info("unlink cleanup rx %lu\n", unlink->unlink_seqnum);
+ if (unlink_list == &vdev->unlink_tx)
+ pr_info("unlink cleanup tx %lu\n",
+ unlink->unlink_seqnum);
+ else
+ pr_info("unlink cleanup rx %lu\n",
+ unlink->unlink_seqnum);
urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
if (!urb) {
@@ -1001,6 +1004,24 @@ static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
spin_unlock_irqrestore(&vhci->lock, flags);
}
+static inline void vhci_cleanup_unlink_tx(struct vhci_device *vdev)
+{
+ __vhci_cleanup_unlink_list(vdev, &vdev->unlink_tx);
+}
+
+static inline void vhci_cleanup_unlink_rx(struct vhci_device *vdev)
+{
+ __vhci_cleanup_unlink_list(vdev, &vdev->unlink_rx);
+}
+
+static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
+{
+ /* give back URBs of unsent unlink requests */
+ vhci_cleanup_unlink_tx(vdev);
+ /* give back URBs of unanswered unlink requests */
+ vhci_cleanup_unlink_rx(vdev);
+}
+
/*
* The important thing is that only one context begins cleanup.
* This is why error handling and cleanup become simple.
--
2.26.2
next reply other threads:[~2021-08-06 16:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-06 16:40 Anirudh Rayabharam [this message]
2021-08-06 16:47 ` [PATCH] usbip: give back URBs for unsent unlink requests during cleanup Greg Kroah-Hartman
2021-08-06 17:16 ` Anirudh Rayabharam
2021-08-13 6:55 ` Greg Kroah-Hartman
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