| Message ID | 20230720113142.3070583-1-aman.deep@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | USB: Fix race condition during UVC webcam disconnect | expand |
On Thu, Jul 20, 2023 at 05:01:42PM +0530, Aman Deep wrote: > In the bug happened during uvc webcam disconect,there is race > between stopping a video transfer and usb disconnect.This issue is > reproduced in my system running Linux kernel when UVC webcam play is > stopped and UVC webcam is disconnected at the same time. This causes the > below backtrace: > > [2-3496.7275] PC is at 0xbf418000+0x2d8 [usbcore] > [2-3496.7275] LR is at 0x00000005 > [2-3496.7275] pc : [<bf4182d8>]((usb_ifnum_to_if > </drivers/usb/core/usb.c:283 > [usbcore.ko]>)) lr : [<00000005>]() psr: 20000013 > [2-3496.7275] Function entered at [<bf4182a4>]((usb_ifnum_to_if > </drivers/usb/core/usb.c:275 > [usbcore.ko]>)) (0xbf418000+0x2a4 [usbcore]) from > [<bf423974>]((usb_hcd_alloc_bandwidth > </drivers/usb/core/hcd.c:1947 > [usbcore.ko]>)) (0xbf418000+0xb974 [usbcore]) > [2-3496.7275] Function entered at [<bf423738>]((usb_hcd_alloc_bandwidth > </drivers/usb/core/hcd.c:1876 > [usbcore.ko]>)) (0xbf418000+0xb738 [usbcore]) from > [<bf426ca0>]((usb_set_interface > </drivers/usb/core/message.c:1461 > [usbcore.ko]>)) (0xbf418000+0xeca0 [usbcore]) > [2-3496.7275] Function entered at [<bf426b9c>]((usb_set_interface > </drivers/usb/core/message.c:1385 > [usbcore.ko]>)) (0xbf418000+0xeb9c [usbcore]) from > [<bf9c4dd4>]((uvc_video_clock_cleanup > </drivers/media/usb/uvc/uvc_video.c:598 > uvc_video_stop_streaming > </drivers/media/usb/uvc/uvc_video.c:2221 > [uvcvideo.ko]>)) (0xbf9bd000+0x7dd4 [uvcvideo]) > [2-3496.7275] Function entered at [<bf9c4d98>]((uvc_video_stop_streaming > </drivers/media/usb/uvc/uvc_video.c:2200 > [uvcvideo.ko]>)) (0xbf9bd000+0x7d98 [uvcvideo]) from > [<bf9bfab8>]((spin_lock_irq > </include/linux/spinlock.h:363 > uvc_stop_streaming > </drivers/media/usb/uvc/uvc_queue.c:194 > [uvcvideo.ko]>)) (0xbf9bd000+0x2ab8 [uvcvideo]) > [2-3496.7276] Function entered at [<bf9bfa94>]((uvc_stop_streaming > </drivers/media/usb/uvc/uvc_queue.c:186 > [uvcvideo.ko]>)) (0xbf9bd000+0x2a94 [uvcvideo]) from > [<be307150>]((__read_once_size > </include/linux/compiler.h:290 > (discriminator 1) __vb2_queue_cancel > </drivers/media/common/videobuf2/videobuf2-core.c:1893 > (discriminator 1) [videobuf2_common.ko]>)) (0xbe306000+0x1150 > [videobuf2_common]) > [2-3496.7276] Function entered at [<be307120>]((__vb2_queue_cancel > </drivers/media/common/videobuf2/videobuf2-core.c:1877 > [videobuf2_common.ko]>)) (0xbe306000+0x1120 [videobuf2_common]) from > [<be308894>]((vb2_core_streamoff > </drivers/media/common/videobuf2/videobuf2-core.c:2053 Odd wrapping, please fix. > > This below solution patch fixes this race condition at USB core level > occurring during UVC webcam device disconnect. > > Signed-off-by: Anuj Gupta <anuj01.gupta@samsung.com> > Signed-off-by: Aman Deep <aman.deep@samsung.com> What commit id does this fix? SHould this go to the stable trees? > --- > drivers/usb/core/hcd.c | 7 ++++++- > drivers/usb/core/message.c | 4 ++++ > drivers/usb/core/usb.c | 9 ++++++--- > 3 files changed, 16 insertions(+), 4 deletions(-) Why are you making changes to the core USB stack for a driver bug? > > diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c > index 8300baedafd2..a06452cbbaa4 100644 > --- a/drivers/usb/core/hcd.c > +++ b/drivers/usb/core/hcd.c > @@ -1931,7 +1931,12 @@ int usb_hcd_alloc_bandwidth(struct usb_device *udev, > } > } > if (cur_alt && new_alt) { > - struct usb_interface *iface = usb_ifnum_to_if(udev, > + struct usb_interface *iface; > + > + if (udev->state == USB_STATE_NOTATTACHED) > + return -ENODEV; > + > + iface = usb_ifnum_to_if(udev, > cur_alt->desc.bInterfaceNumber); > > if (!iface) > diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c > index b5811620f1de..f31c7287dc01 100644 > --- a/drivers/usb/core/message.c > +++ b/drivers/usb/core/message.c > @@ -1575,7 +1575,11 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate) > for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++) > iface->cur_altsetting->endpoint[i].streams = 0; > > + if (dev->state == USB_STATE_NOTATTACHED) > + return -ENODEV; > + > ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt); > + Why the extra line? And why can't the state change right after you check for it? What happens if the device is unattached right here? > if (ret < 0) { > dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n", > alternate); > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c > index 901ec732321c..6fb8b14469ae 100644 > --- a/drivers/usb/core/usb.c > +++ b/drivers/usb/core/usb.c > @@ -352,10 +352,13 @@ struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, > > if (!config) > return NULL; > - for (i = 0; i < config->desc.bNumInterfaces; i++) > - if (config->interface[i]->altsetting[0] > - .desc.bInterfaceNumber == ifnum) > + for (i = 0; i < config->desc.bNumInterfaces; i++) { > + if (config->interface[i] && > + config->interface[i]->altsetting[0] > + .desc.bInterfaceNumber == ifnum) { > return config->interface[i]; I don't understand this change, what does it do? Your changelog does not say why you are doing any of this, only that "there is a problem", please explain this better when you resubmit this. thanks, greg k-h
On Thu, Jul 20, 2023 at 05:01:42PM +0530, Aman Deep wrote: > In the bug happened during uvc webcam disconect,there is race > between stopping a video transfer and usb disconnect.This issue is > reproduced in my system running Linux kernel when UVC webcam play is > stopped and UVC webcam is disconnected at the same time. This causes the > below backtrace: > > [2-3496.7275] PC is at 0xbf418000+0x2d8 [usbcore] > [2-3496.7275] LR is at 0x00000005 > [2-3496.7275] pc : [<bf4182d8>]((usb_ifnum_to_if > </drivers/usb/core/usb.c:283 > [usbcore.ko]>)) lr : [<00000005>]() psr: 20000013 > [2-3496.7275] Function entered at [<bf4182a4>]((usb_ifnum_to_if > </drivers/usb/core/usb.c:275 > [usbcore.ko]>)) (0xbf418000+0x2a4 [usbcore]) from > [<bf423974>]((usb_hcd_alloc_bandwidth > </drivers/usb/core/hcd.c:1947 > [usbcore.ko]>)) (0xbf418000+0xb974 [usbcore]) > [2-3496.7275] Function entered at [<bf423738>]((usb_hcd_alloc_bandwidth > </drivers/usb/core/hcd.c:1876 > [usbcore.ko]>)) (0xbf418000+0xb738 [usbcore]) from > [<bf426ca0>]((usb_set_interface > </drivers/usb/core/message.c:1461 > [usbcore.ko]>)) (0xbf418000+0xeca0 [usbcore]) > [2-3496.7275] Function entered at [<bf426b9c>]((usb_set_interface > </drivers/usb/core/message.c:1385 > [usbcore.ko]>)) (0xbf418000+0xeb9c [usbcore]) from > [<bf9c4dd4>]((uvc_video_clock_cleanup > </drivers/media/usb/uvc/uvc_video.c:598 > uvc_video_stop_streaming > </drivers/media/usb/uvc/uvc_video.c:2221 > [uvcvideo.ko]>)) (0xbf9bd000+0x7dd4 [uvcvideo]) > [2-3496.7275] Function entered at [<bf9c4d98>]((uvc_video_stop_streaming > </drivers/media/usb/uvc/uvc_video.c:2200 > [uvcvideo.ko]>)) (0xbf9bd000+0x7d98 [uvcvideo]) from > [<bf9bfab8>]((spin_lock_irq > </include/linux/spinlock.h:363 > uvc_stop_streaming > </drivers/media/usb/uvc/uvc_queue.c:194 > [uvcvideo.ko]>)) (0xbf9bd000+0x2ab8 [uvcvideo]) > [2-3496.7276] Function entered at [<bf9bfa94>]((uvc_stop_streaming > </drivers/media/usb/uvc/uvc_queue.c:186 > [uvcvideo.ko]>)) (0xbf9bd000+0x2a94 [uvcvideo]) from > [<be307150>]((__read_once_size > </include/linux/compiler.h:290 > (discriminator 1) __vb2_queue_cancel > </drivers/media/common/videobuf2/videobuf2-core.c:1893 > (discriminator 1) [videobuf2_common.ko]>)) (0xbe306000+0x1150 > [videobuf2_common]) > [2-3496.7276] Function entered at [<be307120>]((__vb2_queue_cancel > </drivers/media/common/videobuf2/videobuf2-core.c:1877 > [videobuf2_common.ko]>)) (0xbe306000+0x1120 [videobuf2_common]) from > [<be308894>]((vb2_core_streamoff > </drivers/media/common/videobuf2/videobuf2-core.c:2053 This backtrace doesn't show what actually caused the bug. You should have included several lines from the system log _preceding_ the backtrace. Without those lines, we can only guess at what the problem was. > This below solution patch fixes this race condition at USB core level > occurring during UVC webcam device disconnect. How can a race in the UVC driver be fixed by changing the USB core? It seems obvious that the only way to fix such a race is by changing the UVC driver. > Signed-off-by: Anuj Gupta <anuj01.gupta@samsung.com> > Signed-off-by: Aman Deep <aman.deep@samsung.com> > --- > drivers/usb/core/hcd.c | 7 ++++++- > drivers/usb/core/message.c | 4 ++++ > drivers/usb/core/usb.c | 9 ++++++--- > 3 files changed, 16 insertions(+), 4 deletions(-) > > diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c > index 8300baedafd2..a06452cbbaa4 100644 > --- a/drivers/usb/core/hcd.c > +++ b/drivers/usb/core/hcd.c > @@ -1931,7 +1931,12 @@ int usb_hcd_alloc_bandwidth(struct usb_device *udev, > } > } > if (cur_alt && new_alt) { > - struct usb_interface *iface = usb_ifnum_to_if(udev, > + struct usb_interface *iface; > + > + if (udev->state == USB_STATE_NOTATTACHED) > + return -ENODEV; What will happen if the state changes to USB_STATE_NOTATTACHED at this point, after that test was made? > + > + iface = usb_ifnum_to_if(udev, > cur_alt->desc.bInterfaceNumber); > > if (!iface) > diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c > index b5811620f1de..f31c7287dc01 100644 > --- a/drivers/usb/core/message.c > +++ b/drivers/usb/core/message.c > @@ -1575,7 +1575,11 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate) > for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++) > iface->cur_altsetting->endpoint[i].streams = 0; > > + if (dev->state == USB_STATE_NOTATTACHED) > + return -ENODEV; Same question: What happens if the state changes right here? > + > ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt); > + > if (ret < 0) { > dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n", > alternate); > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c > index 901ec732321c..6fb8b14469ae 100644 > --- a/drivers/usb/core/usb.c > +++ b/drivers/usb/core/usb.c > @@ -352,10 +352,13 @@ struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, > > if (!config) > return NULL; > - for (i = 0; i < config->desc.bNumInterfaces; i++) > - if (config->interface[i]->altsetting[0] > - .desc.bInterfaceNumber == ifnum) > + for (i = 0; i < config->desc.bNumInterfaces; i++) { > + if (config->interface[i] && This new test can fail only if the routine is called after (or while) the device is unconfigured or removed. But if a driver makes such a call then the driver is buggy. The proper solution is to fix the driver, not add this test here. Besides, this test has the same problem as the others you added above. What happens if config->interface[i] gets set to NULL right here? Alan Stern > + config->interface[i]->altsetting[0] > + .desc.bInterfaceNumber == ifnum) { > return config->interface[i]; > + } > + } > > return NULL; > } > -- > 2.34.1 >
Hi Aman,
kernel test robot noticed the following build warnings:
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Aman-Deep/USB-Fix-race-condition-during-UVC-webcam-disconnect/20230720-202046
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@intel.com/config)
compiler: hppa-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230727/202307270834.rpaexQSs-lkp@intel.com/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@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202307270834.rpaexQSs-lkp@intel.com/
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?
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 8300baedafd2..a06452cbbaa4 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1931,7 +1931,12 @@ int usb_hcd_alloc_bandwidth(struct usb_device *udev, } } if (cur_alt && new_alt) { - struct usb_interface *iface = usb_ifnum_to_if(udev, + struct usb_interface *iface; + + if (udev->state == USB_STATE_NOTATTACHED) + return -ENODEV; + + iface = usb_ifnum_to_if(udev, cur_alt->desc.bInterfaceNumber); if (!iface) diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index b5811620f1de..f31c7287dc01 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1575,7 +1575,11 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate) for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++) iface->cur_altsetting->endpoint[i].streams = 0; + if (dev->state == USB_STATE_NOTATTACHED) + return -ENODEV; + ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt); + if (ret < 0) { dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n", alternate); diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index 901ec732321c..6fb8b14469ae 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -352,10 +352,13 @@ struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, if (!config) return NULL; - for (i = 0; i < config->desc.bNumInterfaces; i++) - if (config->interface[i]->altsetting[0] - .desc.bInterfaceNumber == ifnum) + for (i = 0; i < config->desc.bNumInterfaces; i++) { + if (config->interface[i] && + config->interface[i]->altsetting[0] + .desc.bInterfaceNumber == ifnum) { return config->interface[i]; + } + } return NULL; }