From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from galahad.ideasonboard.com ([185.26.127.97]:54653 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935006AbdIZMvA (ORCPT ); Tue, 26 Sep 2017 08:51:00 -0400 From: Laurent Pinchart To: Andrey Konovalov Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, LKML , Dmitry Vyukov , Kostya Serebryany , syzkaller Subject: Re: usb/media/uvc: warning in uvc_scan_chain_forward/__list_add Date: Tue, 26 Sep 2017 15:50:58 +0300 Message-ID: <5144922.ruhMihuH9L@avalon> In-Reply-To: References: <2018643.XCel7AsVXx@avalon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Andrey, On Tuesday, 26 September 2017 15:41:45 EEST Andrey Konovalov wrote: > On Tue, Sep 26, 2017 at 10:43 AM, Laurent Pinchart wrote: > > On Monday, 25 September 2017 15:40:13 EEST Andrey Konovalov wrote: > >> Hi! > >> > >> I've got the following report while fuzzing the kernel with syzkaller. > > > > Thank you for the report. > > > >> On commit e19b205be43d11bff638cad4487008c48d21c103 (4.14-rc2). > >> > >> list_add double add: new=ffff880069084010, prev=ffff880069084010, > >> next=ffff880067d22298. > >> ------------[ cut here ]------------ > >> WARNING: CPU: 1 PID: 1846 at lib/list_debug.c:31 > >> __list_add_valid+0xbd/0xf0 > >> Modules linked in: > >> CPU: 1 PID: 1846 Comm: kworker/1:2 Not tainted > >> 4.14.0-rc2-42613-g1488251d1a98 #238 > >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs > >> 01/01/2011 Workqueue: usb_hub_wq hub_event > >> task: ffff88006b01ca40 task.stack: ffff880064358000 > >> RIP: 0010:__list_add_valid+0xbd/0xf0 lib/list_debug.c:29 > >> RSP: 0018:ffff88006435ddd0 EFLAGS: 00010286 > >> RAX: 0000000000000058 RBX: ffff880067d22298 RCX: 0000000000000000 > >> RDX: 0000000000000058 RSI: ffffffff85a58800 RDI: ffffed000c86bbac > >> RBP: ffff88006435dde8 R08: 1ffff1000c86ba52 R09: 0000000000000000 > >> R10: 0000000000000002 R11: 0000000000000000 R12: ffff880069084010 > >> R13: ffff880067d22298 R14: ffff880069084010 R15: ffff880067d222a0 > >> FS: 0000000000000000(0000) GS:ffff88006c900000(0000) > >> knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > >> CR2: 0000000020004ff2 CR3: 000000006b447000 CR4: 00000000000006e0 > >> > >> Call Trace: > >> __list_add ./include/linux/list.h:59 > >> list_add_tail+0x8c/0x1b0 ./include/linux/list.h:92 > >> uvc_scan_chain_forward.isra.8+0x373/0x416 > >> > >> drivers/media/usb/uvc/uvc_driver.c:1471 > >> > >> uvc_scan_chain drivers/media/usb/uvc/uvc_driver.c:1585 > >> uvc_scan_device drivers/media/usb/uvc/uvc_driver.c:1769 > >> uvc_probe+0x77f2/0x8f00 drivers/media/usb/uvc/uvc_driver.c:2104 > > > > So the issue happens at probe time, before the driver registers the V4L2 > > device nodes that allow userspace access to the device. I wonder how > > fuzzing caused this. Do you have a more detailed log ? > > > > Could you also tell me what webcam you're using to test this out ? The > > output of lsusb -v would be useful. > > Hi Laurent, > > I fuzz the USB stack externally by emulating random USB devices via > dummy_hcd and gadgetfs. Ah that makes more sense indeed. > lsusb -v doesn't show anything, since the USB device doesn't finish > initialization. > > Since I'm able to reproduce this, I can collect debug traces for you. Could you send me the descriptors that your gadget driver returns to the host ? If that's difficult, as an alternative, could you enable tracing in the uvcvideo driver (uvcvideo.trace=0xffff on the kernel commmand line for instance) and send me the kernel log ? > Here's a part of the log around the warning report: > > gadgetfs: bound to dummy_udc driver > usb 1-1: new full-speed USB device number 2 using dummy_hcd > gadgetfs: connected > gadgetfs: disconnected > gadgetfs: connected > usb 1-1: config 3 has an invalid interface number: 3 but max is 0 > usb 1-1: config 3 contains an unexpected descriptor of type 0x1, skipping > usb 1-1: config 3 has an invalid descriptor of length 208, skipping > remainder of the config > usb 1-1: config 3 has no interface number 0 > usb 1-1: New USB device found, idVendor=07f5, idProduct=03ff > usb 1-1: New USB device strings: Mfr=83, Product=255, SerialNumber=5 > usb 1-1: Product: a > usb 1-1: Manufacturer: a > usb 1-1: SerialNumber: a > gadgetfs: configuration #3 > uvcvideo: Found UVC 0.00 device a (07f5:03ff) > list_add double add: new=ffff880069a64910, prev=ffff880069a64910, > next=ffff8800698468d8. > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 1846 at lib/list_debug.c:31 __list_add_valid+0xbd/0xf0 > ... > ---[ end trace ea45186b02846d5a ]--- > uvcvideo 1-1:3.3: Entity type for entity a was not initialized! > gadgetfs: disconnected > usb 1-1: USB disconnect, device number 2 > > Thanks! > > >> usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361 > >> really_probe drivers/base/dd.c:413 > >> driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 > >> __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 > >> bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 > >> __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 > >> device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 > >> bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 > >> device_add+0xd0b/0x1660 drivers/base/core.c:1835 > >> usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932 > >> generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174 > >> usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266 > >> really_probe drivers/base/dd.c:413 > >> driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 > >> __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 > >> bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 > >> __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 > >> device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 > >> bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 > >> device_add+0xd0b/0x1660 drivers/base/core.c:1835 > >> usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457 > >> hub_port_connect drivers/usb/core/hub.c:4903 > >> hub_port_connect_change drivers/usb/core/hub.c:5009 > >> port_event drivers/usb/core/hub.c:5115 > >> hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195 > >> process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119 > >> worker_thread+0x221/0x1850 kernel/workqueue.c:2253 > >> kthread+0x3a1/0x470 kernel/kthread.c:231 > >> ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 > >> > >> Code: f1 48 c7 c7 c0 89 a5 85 48 89 de e8 38 34 e1 fe 0f ff 31 c0 eb > >> c3 48 89 f2 48 89 d9 4c 89 e6 48 c7 c7 40 8a a5 85 e8 1d 34 e1 fe <0f> > >> ff 31 c0 eb a8 48 89 75 e8 e8 e4 b3 2a ff 48 8b 75 e8 e9 5b > >> ---[ end trace 23181469b7a6915e ]--- -- Regards, Laurent Pinchart