RE: Re: [PATCH] USB: Fix race condition during UVC webcam disconnect
From: AMAN DEEP
Date: Fri Jul 28 2023 - 01:29:09 EST
Thanks Den Carpenter for information.
yes, i will modify new patch version accordingly to add for mutex_unlock(hcd->bandwidth_mutex); before returning.
>Hi Aman,
>
>kernel test robot noticed the following build warnings:
>
>https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
>url: https://protect2.fireeye.com/v1/url?k=c33c7aba-a2b76f89-c33df1f5-000babff9bb7-672d2cfefe2327a5&q=1&e=0dbea670-3cf3-4a45-a999->157e4e0dcad9&u=https%3A%2F%2Fgithub.com%2Fintel-lab-lkp%2Flinux%2Fcommits%2FAman-Deep%2FUSB-Fix-race-condition-during-UVC-webcam-disconnect%2F20230720->202046
>base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
>patch link: https://lore.kernel.org/r/20230720113142.3070583-1-aman.deep%40samsung.com
>patch subject: [PATCH] USB: Fix race condition during UVC webcam disconnect
>config: parisc-randconfig-m041-20230726 (https://download.01.org/0day-ci/archive/20230727/202307270834.rpaexQSs-lkp@xxxxxxxxx/config)
>compiler: hppa-linux-gcc (GCC) 12.3.0
>reproduce: (https://download.01.org/0day-ci/archive/20230727/202307270834.rpaexQSs-lkp@xxxxxxxxx/reproduce)
>
>If you fix the issue in a separate patch/commit (i.e. not just a new version of
>the same patch/commit), kindly add following tags
>| Reported-by: kernel test robot <lkp@xxxxxxxxx>
>| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>| Closes: https://lore.kernel.org/r/202307270834.rpaexQSs-lkp@xxxxxxxxx/
we will add it when creating new patch version.
>
>smatch warnings:
>drivers/usb/core/message.c:1668 usb_set_interface() warn: inconsistent returns 'hcd->bandwidth_mutex'.
>
>vim +1668 drivers/usb/core/message.c
>
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1528 int usb_set_interface(struct usb_device *dev, int interface, int alternate)
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1529 {
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1530 struct usb_interface *iface;
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1531 struct usb_host_interface *alt;
>3f0479e00a3fca Sarah Sharp 2009-12-03 1532 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
>7a7b562d08ad6d Hans de Goede 2013-11-08 1533 int i, ret, manual = 0;
>3e35bf39e0b909 Greg Kroah-Hartman 2008-01-30 1534 unsigned int epaddr;
>3e35bf39e0b909 Greg Kroah-Hartman 2008-01-30 1535 unsigned int pipe;
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1536
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1537 if (dev->state == USB_STATE_SUSPENDED)
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1538 return -EHOSTUNREACH;
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1539
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1540 iface = usb_ifnum_to_if(dev, interface);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1541 if (!iface) {
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1542 dev_dbg(&dev->dev, "selecting invalid interface %d\n",
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1543 interface);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1544 return -EINVAL;
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1545 }
>e534c5b831c8b8 Alan Stern 2011-07-01 1546 if (iface->unregistering)
>e534c5b831c8b8 Alan Stern 2011-07-01 1547 return -ENODEV;
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1548
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1549 alt = usb_altnum_to_altsetting(iface, alternate);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1550 if (!alt) {
>385f690bc058ba Thadeu Lima de Souza Cascardo 2010-01-17 1551 dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
>3b6004f3b5a8b4 Greg Kroah-Hartman 2008-08-14 1552 alternate);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1553 return -EINVAL;
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1554 }
>f9a5b4f58b280c Mathias Nyman 2018-09-03 1555 /*
>f9a5b4f58b280c Mathias Nyman 2018-09-03 1556 * usb3 hosts configure the interface in usb_hcd_alloc_bandwidth,
>f9a5b4f58b280c Mathias Nyman 2018-09-03 1557 * including freeing dropped endpoint ring buffers.
>f9a5b4f58b280c Mathias Nyman 2018-09-03 1558 * Make sure the interface endpoints are flushed before that
>f9a5b4f58b280c Mathias Nyman 2018-09-03 1559 */
>f9a5b4f58b280c Mathias Nyman 2018-09-03 1560 usb_disable_interface(dev, iface, false);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1561
>3f0479e00a3fca Sarah Sharp 2009-12-03 1562 /* Make sure we have enough bandwidth for this alternate interface.
>3f0479e00a3fca Sarah Sharp 2009-12-03 1563 * Remove the current alt setting and add the new alt setting.
>3f0479e00a3fca Sarah Sharp 2009-12-03 1564 */
>d673bfcbfffdeb Sarah Sharp 2010-10-15 1565 mutex_lock(hcd->bandwidth_mutex);
>8306095fd2c110 Sarah Sharp 2012-05-02 1566 /* Disable LPM, and re-enable it once the new alt setting is installed,
>8306095fd2c110 Sarah Sharp 2012-05-02 1567 * so that the xHCI driver can recalculate the U1/U2 timeouts.
>8306095fd2c110 Sarah Sharp 2012-05-02 1568 */
>8306095fd2c110 Sarah Sharp 2012-05-02 1569 if (usb_disable_lpm(dev)) {
>1ccc417e6c3201 Joe Perches 2017-12-05 1570 dev_err(&iface->dev, "%s Failed to disable LPM\n", __func__);
>8306095fd2c110 Sarah Sharp 2012-05-02 1571 mutex_unlock(hcd->bandwidth_mutex);
>8306095fd2c110 Sarah Sharp 2012-05-02 1572 return -ENOMEM;
>8306095fd2c110 Sarah Sharp 2012-05-02 1573 }
>7a7b562d08ad6d Hans de Goede 2013-11-08 1574 /* Changing alt-setting also frees any allocated streams */
>7a7b562d08ad6d Hans de Goede 2013-11-08 1575 for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)
>7a7b562d08ad6d Hans de Goede 2013-11-08 1576 iface->cur_altsetting->endpoint[i].streams = 0;
>7a7b562d08ad6d Hans de Goede 2013-11-08 1577
>4682bbb9e2f196 Aman Deep 2023-07-20 1578 if (dev->state == USB_STATE_NOTATTACHED)
>4682bbb9e2f196 Aman Deep 2023-07-20 1579 return -ENODEV;
>
>
>mutex_unlock(hcd->bandwidth_mutex); before returning
>
>4682bbb9e2f196 Aman Deep 2023-07-20 1580
>3f0479e00a3fca Sarah Sharp 2009-12-03 1581 ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
>4682bbb9e2f196 Aman Deep 2023-07-20 1582
>3f0479e00a3fca Sarah Sharp 2009-12-03 1583 if (ret < 0) {
>3f0479e00a3fca Sarah Sharp 2009-12-03 1584 dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
>3f0479e00a3fca Sarah Sharp 2009-12-03 1585 alternate);
>8306095fd2c110 Sarah Sharp 2012-05-02 1586 usb_enable_lpm(dev);
>d673bfcbfffdeb Sarah Sharp 2010-10-15 1587 mutex_unlock(hcd->bandwidth_mutex);
>3f0479e00a3fca Sarah Sharp 2009-12-03 1588 return ret;
>3f0479e00a3fca Sarah Sharp 2009-12-03 1589 }
>3f0479e00a3fca Sarah Sharp 2009-12-03 1590
>392e1d9817d002 Alan Stern 2008-03-11 1591 if (dev->quirks & USB_QUIRK_NO_SET_INTF)
>392e1d9817d002 Alan Stern 2008-03-11 1592 ret = -EPIPE;
>392e1d9817d002 Alan Stern 2008-03-11 1593 else
>297e84c04d76b9 Greg Kroah-Hartman 2020-09-14 1594 ret = usb_control_msg_send(dev, 0,
>297e84c04d76b9 Greg Kroah-Hartman 2020-09-14 1595 USB_REQ_SET_INTERFACE,
>297e84c04d76b9 Greg Kroah-Hartman 2020-09-14 1596 USB_RECIP_INTERFACE, alternate,
>ddd1198e3e0935 Oliver Neukum 2020-09-23 1597 interface, NULL, 0, 5000,
>ddd1198e3e0935 Oliver Neukum 2020-09-23 1598 GFP_NOIO);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1599
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1600 /* 9.4.10 says devices don't need this and are free to STALL the
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1601 * request if the interface only has one alternate setting.
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1602 */
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1603 if (ret == -EPIPE && iface->num_altsetting == 1) {
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1604 dev_dbg(&dev->dev,
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1605 "manual set_interface for iface %d, alt %d\n",
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1606 interface, alternate);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1607 manual = 1;
>297e84c04d76b9 Greg Kroah-Hartman 2020-09-14 1608 } else if (ret) {
>3f0479e00a3fca Sarah Sharp 2009-12-03 1609 /* Re-instate the old alt setting */
>3f0479e00a3fca Sarah Sharp 2009-12-03 1610 usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
>8306095fd2c110 Sarah Sharp 2012-05-02 1611 usb_enable_lpm(dev);
>d673bfcbfffdeb Sarah Sharp 2010-10-15 1612 mutex_unlock(hcd->bandwidth_mutex);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1613 return ret;
>3f0479e00a3fca Sarah Sharp 2009-12-03 1614 }
>d673bfcbfffdeb Sarah Sharp 2010-10-15 1615 mutex_unlock(hcd->bandwidth_mutex);
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1616
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1617 /* FIXME drivers shouldn't need to replicate/bugfix the logic here
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1618 * when they implement async or easily-killable versions of this or
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1619 * other "should-be-internal" functions (like clear_halt).
>^1da177e4c3f41 Linus Torvalds 2005-04-16 1620 * should hcd+usbcore postprocess control requests?
>
>--
>0-DAY CI Kernel Test Service
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>
>
Thanks,
Aman