ea427a222d
The initial value of hid->collection[].parent_idx if 0. When Report descriptor doesn't contain "HID Collection", the value remains as 0. In the meanwhile, when the Report descriptor fullfill all following conditions, it will trigger hid_apply_multiplier function call. 1. Usage page is Generic Desktop Ctrls (0x01) 2. Usage is RESOLUTION_MULTIPLIER (0x48) 3. Contain any FEATURE items The while loop in hid_apply_multiplier will search the top-most collection by searching parent_idx == -1. Because all parent_idx is 0. The loop will run forever. There is a Report Descriptor triggerring the deadloop 0x05, 0x01, // Usage Page (Generic Desktop Ctrls) 0x09, 0x48, // Usage (0x48) 0x95, 0x01, // Report Count (1) 0x75, 0x08, // Report Size (8) 0xB1, 0x01, // Feature Signed-off-by: Xin Zhao <xnzhao@google.com> Link: https://lore.kernel.org/r/20230130212947.1315941-1-xnzhao@google.com Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
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.