Re: usb/core: warning in usb_create_ep_devs/sysfs_create_dir_ns

From: Andrey Konovalov <andreyknvl@google.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	USB list <linux-usb@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Dmitry Vyukov <dvyukov@google.com>,
	Kostya Serebryany <kcc@google.com>,
	syzkaller <syzkaller@googlegroups.com>
Subject: Re: usb/core: warning in usb_create_ep_devs/sysfs_create_dir_ns
Date: Sat, 17 Dec 2016 18:12:25 +0100	[thread overview]
Message-ID: <CAAeHK+xS37X0xQm3f0cus649Uv91pO6A7SMcv3rssMfN+JBvdQ@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1612161300240.1533-100000@iolanthe.rowland.org>

On Fri, Dec 16, 2016 at 7:01 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Mon, 12 Dec 2016, Andrey Konovalov wrote:
>
>> Hi!
>>
>> While running the syzkaller fuzzer I've got the following error report.
>>
>> On commit 3c49de52d5647cda8b42c4255cf8a29d1e22eff5 (Dev 2).
>>
>> WARNING: CPU: 2 PID: 865 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x8a/0xa0
>> gadgetfs: disconnected
>> sysfs: cannot create duplicate filename
>> '/devices/platform/dummy_hcd.0/usb2/2-1/2-1:64.0/ep_05'
>> Kernel panic - not syncing: panic_on_warn set ...
>>
>> CPU: 2 PID: 865 Comm: kworker/2:1 Not tainted 4.9.0-rc7+ #34
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>> Workqueue: usb_hub_wq hub_event
>>  ffff88006bee64c8 ffffffff81f96b8a ffffffff00000001 1ffff1000d7dcc2c
>>  ffffed000d7dcc24 0000000000000001 0000000041b58ab3 ffffffff8598b510
>>  ffffffff81f968f8 ffffffff850fee20 ffffffff85cff020 dffffc0000000000
>> Call Trace:
>>  [<     inline     >] __dump_stack lib/dump_stack.c:15
>>  [<ffffffff81f96b8a>] dump_stack+0x292/0x398 lib/dump_stack.c:51
>>  [<ffffffff8168c88e>] panic+0x1cb/0x3a9 kernel/panic.c:179
>>  [<ffffffff812b80b4>] __warn+0x1c4/0x1e0 kernel/panic.c:542
>>  [<ffffffff812b8195>] warn_slowpath_fmt+0xc5/0x110 kernel/panic.c:565
>>  [<ffffffff819e70ca>] sysfs_warn_dup+0x8a/0xa0 fs/sysfs/dir.c:30
>>  [<ffffffff819e7308>] sysfs_create_dir_ns+0x178/0x1d0 fs/sysfs/dir.c:59
>>  [<     inline     >] create_dir lib/kobject.c:71
>>  [<ffffffff81fa1b07>] kobject_add_internal+0x227/0xa60 lib/kobject.c:229
>>  [<     inline     >] kobject_add_varg lib/kobject.c:366
>>  [<ffffffff81fa2479>] kobject_add+0x139/0x220 lib/kobject.c:411
>>  [<ffffffff82737a63>] device_add+0x353/0x1660 drivers/base/core.c:1088
>>  [<ffffffff82738d8d>] device_register+0x1d/0x20 drivers/base/core.c:1206
>>  [<ffffffff82cb77d3>] usb_create_ep_devs+0x163/0x260
>> drivers/usb/core/endpoint.c:195
>>  [<ffffffff82c9f27b>] create_intf_ep_devs+0x13b/0x200
>> drivers/usb/core/message.c:1030
>>  [<ffffffff82ca39d3>] usb_set_configuration+0x1083/0x18d0
>> drivers/usb/core/message.c:1937
>
> Hi, Andrey:
>
> Please check whether the patch below fixes this problem.

Hi Alan,

Been testing with your patch for the last day, haven't seen any more
reports or other issues.

Tested-by: Andrey Konovalov <andreyknvl@google.com>

Thanks!

>
> Alan Stern
>
>
>
> Index: usb-4.x/drivers/usb/core/config.c
> ===================================================================
> --- usb-4.x.orig/drivers/usb/core/config.c
> +++ usb-4.x/drivers/usb/core/config.c
> @@ -234,6 +234,16 @@ static int usb_parse_endpoint(struct dev
>         if (ifp->desc.bNumEndpoints >= num_ep)
>                 goto skip_to_next_endpoint_or_interface_descriptor;
>
> +       /* Check for duplicate endpoint addresses */
> +       for (i = 0; i < ifp->desc.bNumEndpoints; ++i) {
> +               if (ifp->endpoint[i].desc.bEndpointAddress ==
> +                   d->bEndpointAddress) {
> +                       dev_warn(ddev, "config %d interface %d altsetting %d has a duplicate endpoint with address 0x%X, skipping\n",
> +                           cfgno, inum, asnum, d->bEndpointAddress);
> +                       goto skip_to_next_endpoint_or_interface_descriptor;
> +               }
> +       }
> +
>         endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
>         ++ifp->desc.bNumEndpoints;
>
>