59bed79ffd
The WARN_ON_ONCE() in ct_kernel_exit_state() follows the call to ct_state_inc(), which means that RCU is not watching this WARN_ON_ONCE(). This can (and does) result in extraneous lockdep warnings when this WARN_ON_ONCE() triggers. These extraneous warnings are the opposite of helpful. Therefore, invert the WARN_ON_ONCE() condition and move it before the call to ct_state_inc(). This does mean that the ct_state_inc() return value can no longer be used in the WARN_ON_ONCE() condition, so discard this return value and instead use a call to rcu_is_watching_curr_cpu(). This call is executed only in CONFIG_RCU_EQS_DEBUG=y kernels, so there is no added overhead in production use. [Boqun: Add the subsystem tag in the title] Reported-by: Breno Leitao <leitao@debian.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Valentin Schneider <vschneid@redhat.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/bd911cd9-1fe9-447c-85e0-ea811a1dc896@paulmck-laptop Signed-off-by: Boqun Feng <boqun.feng@gmail.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 reStructuredText 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.