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Subject[PATCH 4.9 24/83] usbip: usbip_host: fix BUG: sleeping function called from invalid context
Date
From: Shuah Khan <skhan@linuxfoundation.org>

commit 0c9e8b3cad654bfc499c10b652fbf8f0b890af8f upstream.

stub_probe() and stub_disconnect() call functions which could call
sleeping function in invalid context whil holding busid_lock.

Fix the problem by refining the lock holds to short critical sections
to change the busid_priv fields. This fix restructures the code to
limit the lock holds in stub_probe() and stub_disconnect().

stub_probe():

[15217.927028] BUG: sleeping function called from invalid context at mm/slab.h:418
[15217.927038] in_atomic(): 1, irqs_disabled(): 0, pid: 29087, name: usbip
[15217.927044] 5 locks held by usbip/29087:
[15217.927047] #0: 0000000091647f28 (sb_writers#6){....}, at: vfs_write+0x191/0x1c0
[15217.927062] #1: 000000008f9ba75b (&of->mutex){....}, at: kernfs_fop_write+0xf7/0x1b0
[15217.927072] #2: 00000000872e5b4b (&dev->mutex){....}, at: __device_driver_lock+0x3b/0x50
[15217.927082] #3: 00000000e74ececc (&dev->mutex){....}, at: __device_driver_lock+0x46/0x50
[15217.927090] #4: 00000000b20abbe0 (&(&busid_table[i].busid_lock)->rlock){....}, at: get_busid_priv+0x48/0x60 [usbip_host]
[15217.927103] CPU: 3 PID: 29087 Comm: usbip Tainted: G W 5.1.0-rc6+ #40
[15217.927106] Hardware name: Dell Inc. OptiPlex 790/0HY9JP, BIOS A18 09/24/2013
[15217.927109] Call Trace:
[15217.927118] dump_stack+0x63/0x85
[15217.927127] ___might_sleep+0xff/0x120
[15217.927133] __might_sleep+0x4a/0x80
[15217.927143] kmem_cache_alloc_trace+0x1aa/0x210
[15217.927156] stub_probe+0xe8/0x440 [usbip_host]
[15217.927171] usb_probe_device+0x34/0x70

stub_disconnect():

[15279.182478] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908
[15279.182487] in_atomic(): 1, irqs_disabled(): 0, pid: 29114, name: usbip
[15279.182492] 5 locks held by usbip/29114:
[15279.182494] #0: 0000000091647f28 (sb_writers#6){....}, at: vfs_write+0x191/0x1c0
[15279.182506] #1: 00000000702cf0f3 (&of->mutex){....}, at: kernfs_fop_write+0xf7/0x1b0
[15279.182514] #2: 00000000872e5b4b (&dev->mutex){....}, at: __device_driver_lock+0x3b/0x50
[15279.182522] #3: 00000000e74ececc (&dev->mutex){....}, at: __device_driver_lock+0x46/0x50
[15279.182529] #4: 00000000b20abbe0 (&(&busid_table[i].busid_lock)->rlock){....}, at: get_busid_priv+0x48/0x60 [usbip_host]
[15279.182541] CPU: 0 PID: 29114 Comm: usbip Tainted: G W 5.1.0-rc6+ #40
[15279.182543] Hardware name: Dell Inc. OptiPlex 790/0HY9JP, BIOS A18 09/24/2013
[15279.182546] Call Trace:
[15279.182554] dump_stack+0x63/0x85
[15279.182561] ___might_sleep+0xff/0x120
[15279.182566] __might_sleep+0x4a/0x80
[15279.182574] __mutex_lock+0x55/0x950
[15279.182582] ? get_busid_priv+0x48/0x60 [usbip_host]
[15279.182587] ? reacquire_held_locks+0xec/0x1a0
[15279.182591] ? get_busid_priv+0x48/0x60 [usbip_host]
[15279.182597] ? find_held_lock+0x94/0xa0
[15279.182609] mutex_lock_nested+0x1b/0x20
[15279.182614] ? mutex_lock_nested+0x1b/0x20
[15279.182618] kernfs_remove_by_name_ns+0x2a/0x90
[15279.182625] sysfs_remove_file_ns+0x15/0x20
[15279.182629] device_remove_file+0x19/0x20
[15279.182634] stub_disconnect+0x6d/0x180 [usbip_host]
[15279.182643] usb_unbind_device+0x27/0x60

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/usbip/stub_dev.c | 65 ++++++++++++++++++++++++++++---------------
1 file changed, 43 insertions(+), 22 deletions(-)

--- a/drivers/usb/usbip/stub_dev.c
+++ b/drivers/usb/usbip/stub_dev.c
@@ -315,9 +315,17 @@ static int stub_probe(struct usb_device
const char *udev_busid = dev_name(&udev->dev);
struct bus_id_priv *busid_priv;
int rc = 0;
+ char save_status;

dev_dbg(&udev->dev, "Enter probe\n");

+ /* Not sure if this is our device. Allocate here to avoid
+ * calling alloc while holding busid_table lock.
+ */
+ sdev = stub_device_alloc(udev);
+ if (!sdev)
+ return -ENOMEM;
+
/* check we should claim or not by busid_table */
busid_priv = get_busid_priv(udev_busid);
if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
@@ -332,14 +340,14 @@ static int stub_probe(struct usb_device
* See driver_probe_device() in driver/base/dd.c
*/
rc = -ENODEV;
- goto call_put_busid_priv;
+ goto sdev_free;
}

if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
udev_busid);
rc = -ENODEV;
- goto call_put_busid_priv;
+ goto sdev_free;
}

if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
@@ -348,15 +356,9 @@ static int stub_probe(struct usb_device
udev_busid);

rc = -ENODEV;
- goto call_put_busid_priv;
+ goto sdev_free;
}

- /* ok, this is my device */
- sdev = stub_device_alloc(udev);
- if (!sdev) {
- rc = -ENOMEM;
- goto call_put_busid_priv;
- }

dev_info(&udev->dev,
"usbip-host: register new device (bus %u dev %u)\n",
@@ -366,9 +368,13 @@ static int stub_probe(struct usb_device

/* set private data to usb_device */
dev_set_drvdata(&udev->dev, sdev);
+
busid_priv->sdev = sdev;
busid_priv->udev = udev;

+ save_status = busid_priv->status;
+ busid_priv->status = STUB_BUSID_ALLOC;
+
/*
* Claim this hub port.
* It doesn't matter what value we pass as owner
@@ -381,15 +387,16 @@ static int stub_probe(struct usb_device
goto err_port;
}

+ /* release the busid_lock */
+ put_busid_priv(busid_priv);
+
rc = stub_add_files(&udev->dev);
if (rc) {
dev_err(&udev->dev, "stub_add_files for %s\n", udev_busid);
goto err_files;
}
- busid_priv->status = STUB_BUSID_ALLOC;

- rc = 0;
- goto call_put_busid_priv;
+ return 0;

err_files:
usb_hub_release_port(udev->parent, udev->portnum,
@@ -398,23 +405,24 @@ err_port:
dev_set_drvdata(&udev->dev, NULL);
usb_put_dev(udev);

+ /* we already have busid_priv, just lock busid_lock */
+ spin_lock(&busid_priv->busid_lock);
busid_priv->sdev = NULL;
+ busid_priv->status = save_status;
+sdev_free:
stub_device_free(sdev);
-
-call_put_busid_priv:
+ /* release the busid_lock */
put_busid_priv(busid_priv);
+
return rc;
}

static void shutdown_busid(struct bus_id_priv *busid_priv)
{
- if (busid_priv->sdev && !busid_priv->shutdown_busid) {
- busid_priv->shutdown_busid = 1;
- usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
+ usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);

- /* wait for the stop of the event handler */
- usbip_stop_eh(&busid_priv->sdev->ud);
- }
+ /* wait for the stop of the event handler */
+ usbip_stop_eh(&busid_priv->sdev->ud);
}

/*
@@ -446,6 +454,9 @@ static void stub_disconnect(struct usb_d

dev_set_drvdata(&udev->dev, NULL);

+ /* release busid_lock before call to remove device files */
+ put_busid_priv(busid_priv);
+
/*
* NOTE: rx/tx threads are invoked for each usb_device.
*/
@@ -456,18 +467,27 @@ static void stub_disconnect(struct usb_d
(struct usb_dev_state *) udev);
if (rc) {
dev_dbg(&udev->dev, "unable to release port\n");
- goto call_put_busid_priv;
+ return;
}

/* If usb reset is called from event handler */
if (usbip_in_eh(current))
- goto call_put_busid_priv;
+ return;
+
+ /* we already have busid_priv, just lock busid_lock */
+ spin_lock(&busid_priv->busid_lock);
+ if (!busid_priv->shutdown_busid)
+ busid_priv->shutdown_busid = 1;
+ /* release busid_lock */
+ put_busid_priv(busid_priv);

/* shutdown the current connection */
shutdown_busid(busid_priv);

usb_put_dev(sdev->udev);

+ /* we already have busid_priv, just lock busid_lock */
+ spin_lock(&busid_priv->busid_lock);
/* free sdev */
busid_priv->sdev = NULL;
stub_device_free(sdev);
@@ -476,6 +496,7 @@ static void stub_disconnect(struct usb_d
busid_priv->status = STUB_BUSID_ADDED;

call_put_busid_priv:
+ /* release busid_lock */
put_busid_priv(busid_priv);
}


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