b891b37591
Background: When CPU is going to idle state, it would inform RCU that current CPU is entering idle through rcu_idle_enter(), and RCU will ignore read-side critical sections of this CPU. However, there is CFI check mechanism inside idle flow and calls rcu_read_lock(), so "rcu_read_lock() used illegally while idle" in rcu_read_lock() will be triggered because rcu_idle_enter() was already called before. Beside, the pointer of rcu_dereference() might be invalid due to the RCU read-side critical sections will be ignoring in this going idle CPU, it might cause problems like: access the wrong data/address, kernel exception... Based on above description: We will add __nocfi to cpuidle_enter_state to avoid “rcu_read_lock() used illegally while idle!” and avoid the usage of invalid pointer of rcu_dereference() in this situation. Bug: 169017431 Change-Id: I8bbe25704e18cfde351a8f4277dd4b44b07421f5 Signed-off-by: rogercl.yang <rogercl.yang@mediatek.com> Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.