[PATCH 3.16 186/370] USB: fix problems with duplicate endpoint addresses

Ben Hutchings
2017-03-10T14:01:04Z

From: Alan Stern <stern@rowland.harvard.edu>

commit 0a8fd1346254974c3a852338508e4a4cddbb35f1 upstream.

When checking a new device's descriptors, the USB core does not check
for duplicate endpoint addresses. This can cause a problem when the
sysfs files for those endpoints are created; trying to create multiple
files with the same name will provoke a WARNING:

WARNING: CPU: 2 PID: 865 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x8a/0xa0
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

This patch prevents the problem by checking for duplicate endpoint
addresses during enumeration and skipping any duplicates.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/core/config.c | 10 ++++++++++
1 file changed, 10 insertions(+)

--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -205,6 +205,16 @@ 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;