usb/core: warning in usb_create_ep_devs/sysfs_create_dir_ns

From: Andrey Konovalov <andreyknvl@google.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	USB list <linux-usb@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Alan Stern <stern@rowland.harvard.edu>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	Kostya Serebryany <kcc@google.com>,
	syzkaller <syzkaller@googlegroups.com>
Subject: usb/core: warning in usb_create_ep_devs/sysfs_create_dir_ns
Date: Mon, 12 Dec 2016 21:48:18 +0100	[thread overview]
Message-ID: <CAAeHK+wnfCUAuN9skpGFsc+diddt0=Vv1+Xq=rzpK3SuzKhQDw@mail.gmail.com> (raw)

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
 [<ffffffff82cc9e2e>] generic_probe+0x6e/0xe0 drivers/usb/core/generic.c:172
 [<ffffffff82caa7fa>] usb_probe_device+0xaa/0xe0 drivers/usb/core/driver.c:263
 [<     inline     >] really_probe drivers/base/dd.c:375
 [<ffffffff82741f64>] driver_probe_device+0x514/0x980 drivers/base/dd.c:515
 [<ffffffff827427bb>] __device_attach_driver+0x22b/0x290 drivers/base/dd.c:610
 [<ffffffff8273b56c>] bus_for_each_drv+0x15c/0x200 drivers/base/bus.c:463
 [<ffffffff82741776>] __device_attach+0x266/0x3c0 drivers/base/dd.c:667
 [<ffffffff827428ba>] device_initial_probe+0x1a/0x20 drivers/base/dd.c:714
 [<ffffffff8273edb6>] bus_probe_device+0x1e6/0x290 drivers/base/bus.c:557
 [<ffffffff82738416>] device_add+0xd06/0x1660 drivers/base/core.c:1136
 [<ffffffff82c8066f>] usb_new_device+0x9af/0x1e80 drivers/usb/core/hub.c:2508
 [<     inline     >] hub_port_connect drivers/usb/core/hub.c:4891
 [<     inline     >] hub_port_connect_change drivers/usb/core/hub.c:4996
 [<     inline     >] port_event drivers/usb/core/hub.c:5102
 [<ffffffff82c84fe9>] hub_event+0x1689/0x36d0 drivers/usb/core/hub.c:5182
 [<ffffffff8132743a>] process_one_work+0xb2a/0x1aa0 kernel/workqueue.c:2096
 [<ffffffff813285bf>] worker_thread+0x20f/0x18a0 kernel/workqueue.c:2230
 [<ffffffff8133ebf3>] kthread+0x323/0x3e0 kernel/kthread.c:209
 [<ffffffff84f4812a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled