bcc963f591
[ Upstream commit 2052138b7da52ad5ccaf74f736d00f39a1c9198c ]
Infinite log printing occurs during fuzz test:
rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
...
dvb-usb: schedule remote query interval to 100 msecs.
dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
dvb-usb: bulk message failed: -22 (1/0)
dvb-usb: bulk message failed: -22 (1/0)
dvb-usb: bulk message failed: -22 (1/0)
...
dvb-usb: bulk message failed: -22 (1/0)
Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
that is in rc_core_dvb_usb_remote_init() create a work that will call
dvb_usb_read_remote_control(), and this work will reschedule itself at
'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
see following code snippet:
rc_core_dvb_usb_remote_init() {
...
INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
schedule_delayed_work(&d->rc_query_work,
msecs_to_jiffies(rc_interval));
...
}
dvb_usb_read_remote_control() {
...
err = d->props.rc.core.rc_query(d);
if (err)
err(...) // Did not return even if query failed
schedule_delayed_work(&d->rc_query_work,
msecs_to_jiffies(rc_interval));
}
When the infinite log printing occurs, the query callback
'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
the failure of finding a valid 'generic_bulk_ctrl_endpoint'
in usb_bulk_msg(), see following code snippet:
cxusb_rc_query() {
cxusb_ctrl_msg() {
dvb_usb_generic_rw() {
ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
d->props.generic_bulk_ctrl_endpoint),...);
if (ret)
err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
...
}
...
}
By analyzing the corresponding USB descriptor, it shows that the
bNumEndpoints is 0 in its interface descriptor, but
the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
'invalid' USB device should be rejected before it calls into
dvb_usb_read_remote_control().
To fix it, we need to add endpoint check for 'generic_bulk_ctrl_endpoint'.
And as Sean suggested, the same check and clear halts should be done for
'generic_bulk_ctrl_endpoint_response'. So introduce
dvb_usb_check_bulk_endpoint() to do it for both of them.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.