From patchwork Fri Aug 26 19:31:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Stern X-Patchwork-Id: 600565 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA52AECAAD6 for ; Fri, 26 Aug 2022 19:31:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344542AbiHZTbj (ORCPT ); Fri, 26 Aug 2022 15:31:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344651AbiHZTbf (ORCPT ); Fri, 26 Aug 2022 15:31:35 -0400 Received: from netrider.rowland.org (netrider.rowland.org [192.131.102.5]) by lindbergh.monkeyblade.net (Postfix) with SMTP id AD5E5E01E6 for ; Fri, 26 Aug 2022 12:31:32 -0700 (PDT) Received: (qmail 48553 invoked by uid 1000); 26 Aug 2022 15:31:32 -0400 Date: Fri, 26 Aug 2022 15:31:32 -0400 From: Alan Stern To: Greg KH Cc: Rondreis , USB mailing list Subject: [PATCH] USB: core: Prevent nested device-reset calls Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Automatic kernel fuzzing revealed a recursive locking violation in usb-storage: ============================================ WARNING: possible recursive locking detected 5.18.0 #3 Not tainted -------------------------------------------- kworker/1:3/1205 is trying to acquire lock: ffff888018638db8 (&us_interface_key[i]){+.+.}-{3:3}, at: usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230 but task is already holding lock: ffff888018638db8 (&us_interface_key[i]){+.+.}-{3:3}, at: usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230 ... stack backtrace: CPU: 1 PID: 1205 Comm: kworker/1:3 Not tainted 5.18.0 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2988 [inline] check_deadlock kernel/locking/lockdep.c:3031 [inline] validate_chain kernel/locking/lockdep.c:3816 [inline] __lock_acquire.cold+0x152/0x3ca kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5665 [inline] lock_acquire+0x1ab/0x520 kernel/locking/lockdep.c:5630 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x14f/0x1610 kernel/locking/mutex.c:747 usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230 usb_reset_device+0x37d/0x9a0 drivers/usb/core/hub.c:6109 r871xu_dev_remove+0x21a/0x270 drivers/staging/rtl8712/usb_intf.c:622 usb_unbind_interface+0x1bd/0x890 drivers/usb/core/driver.c:458 device_remove drivers/base/dd.c:545 [inline] device_remove+0x11f/0x170 drivers/base/dd.c:537 __device_release_driver drivers/base/dd.c:1222 [inline] device_release_driver_internal+0x1a7/0x2f0 drivers/base/dd.c:1248 usb_driver_release_interface+0x102/0x180 drivers/usb/core/driver.c:627 usb_forced_unbind_intf+0x4d/0xa0 drivers/usb/core/driver.c:1118 usb_reset_device+0x39b/0x9a0 drivers/usb/core/hub.c:6114 This turned out not to be an error in usb-storage but rather a nested device reset attempt. That is, as the rtl8712 driver was being unbound from a composite device in preparation for an unrelated USB reset (that driver does not have pre_reset or post_reset callbacks), its ->remove routine called usb_reset_device() -- thus nesting one reset call within another. Performing a reset as part of disconnect processing is a questionable practice at best. However, the bug report points out that the USB core does not have any protection against nested resets. Adding a reset_in_progress flag and testing it will prevent such errors in the future. Reported-and-tested-by: Rondreis Signed-off-by: Alan Stern Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/CAB7eexKUpvX-JNiLzhXBDWgfg2T9e9_0Tw4HQ6keN==voRbP0g@mail.gmail.com/ --- [as1985] drivers/usb/core/hub.c | 10 ++++++++++ include/linux/usb.h | 2 ++ 2 files changed, 12 insertions(+) Index: usb-devel/drivers/usb/core/hub.c =================================================================== --- usb-devel.orig/drivers/usb/core/hub.c +++ usb-devel/drivers/usb/core/hub.c @@ -6038,6 +6038,11 @@ re_enumerate: * the reset is over (using their post_reset method). * * Return: The same as for usb_reset_and_verify_device(). + * However, if a reset is already in progress (for instance, if a + * driver doesn't have pre_ or post_reset() callbacks, and while + * being unbound or re-bound during the ongoing reset its disconnect() + * or probe() routine tries to perform a second, nested reset), the + * routine returns -EINPROGRESS. * * Note: * The caller must own the device lock. For example, it's safe to use @@ -6071,6 +6076,10 @@ int usb_reset_device(struct usb_device * return -EISDIR; } + if (udev->reset_in_progress) + return -EINPROGRESS; + udev->reset_in_progress = 1; + port_dev = hub->ports[udev->portnum - 1]; /* @@ -6135,6 +6144,7 @@ int usb_reset_device(struct usb_device * usb_autosuspend_device(udev); memalloc_noio_restore(noio_flag); + udev->reset_in_progress = 0; return ret; } EXPORT_SYMBOL_GPL(usb_reset_device); Index: usb-devel/include/linux/usb.h =================================================================== --- usb-devel.orig/include/linux/usb.h +++ usb-devel/include/linux/usb.h @@ -575,6 +575,7 @@ struct usb3_lpm_parameters { * @devaddr: device address, XHCI: assigned by HW, others: same as devnum * @can_submit: URBs may be submitted * @persist_enabled: USB_PERSIST enabled for this device + * @reset_in_progress: the device is being reset * @have_langid: whether string_langid is valid * @authorized: policy has said we can use it; * (user space) policy determines if we authorize this device to be @@ -662,6 +663,7 @@ struct usb_device { unsigned can_submit:1; unsigned persist_enabled:1; + unsigned reset_in_progress:1; unsigned have_langid:1; unsigned authorized:1; unsigned authenticated:1;