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usbip: usbip_host: fix BUG: sleeping function called from invalid con…
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commit 0c9e8b3 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>
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@shuahkh @gregkh
shuahkh authored and gregkh committed Jun 9, 2019
1 parent 9690202 commit e3724d6
Showing 1 changed file with 43 additions and 22 deletions.
65 changes: 43 additions & 22 deletions drivers/usb/usbip/stub_dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -301,9 +301,17 @@ static int stub_probe(struct usb_device *udev)
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) ||
Expand All @@ -318,14 +326,14 @@ static int stub_probe(struct usb_device *udev)
* 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")) {
Expand All @@ -334,15 +342,9 @@ static int stub_probe(struct usb_device *udev)
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",
Expand All @@ -352,9 +354,13 @@ static int stub_probe(struct usb_device *udev)

/* 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
Expand All @@ -367,15 +373,16 @@ static int stub_probe(struct usb_device *udev)
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,
Expand All @@ -384,23 +391,24 @@ static int stub_probe(struct usb_device *udev)
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);
}

/*
Expand Down Expand Up @@ -432,6 +440,9 @@ static void stub_disconnect(struct usb_device *udev)

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.
*/
Expand All @@ -442,18 +453,27 @@ static void stub_disconnect(struct usb_device *udev)
(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);
Expand All @@ -462,6 +482,7 @@ static void stub_disconnect(struct usb_device *udev)
busid_priv->status = STUB_BUSID_ADDED;

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

Expand Down

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