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    Subject[PATCH 3.16 186/370] USB: fix problems with duplicate endpoint addresses
    3.16.42-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    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;

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