3.16.75-rc1 review patch. If anyone has any objections, please let me know.
------------------
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [bwh: Backported to 3.16: adjust filename, context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/staging/usbip/stub_dev.c | 65 ++++++++++++++++++++++++------------ 1 file changed, 43 insertions(+), 22 deletions(-)
--- a/drivers/staging/usbip/stub_dev.c +++ b/drivers/staging/usbip/stub_dev.c @@ -342,9 +342,17 @@ 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) || @@ -359,14 +367,14 @@ 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")) { @@ -375,15 +383,9 @@ 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", @@ -393,9 +395,13 @@ 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 @@ -408,15 +414,16 @@ 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, @@ -426,23 +433,24 @@ err_port: usb_put_dev(udev); kthread_stop_put(sdev->ud.eh);
+ /* 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); }
/* @@ -474,6 +482,9 @@ 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. */ @@ -484,18 +495,27 @@ 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 (busid_priv->sdev->ud.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); @@ -504,6 +524,7 @@ 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); }