* Waiman Long <long...@redhat.com> wrote:
> For a rwsem, locking can either be exclusive or shared. The corresponding
> exclusive or shared unlock must be used. Otherwise, the protected data
> structures may get corrupted or the lock may be in an inconsistent state.
>
> In order to detect such anomaly, a new configuration option DEBUG_RWSEMS
> is added which can be enabled to look for such mismatches and print
> warnings that that happens.
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 64155e3..0958192 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1075,6 +1075,13 @@ config DEBUG_WW_MUTEX_SLOWPATH
> even a debug kernel. If you are a driver writer, enable it. If
> you are a distro, do not.
>
> +config DEBUG_RWSEMS
> + bool "RW Semaphore debugging: basic checks"
> + depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER
> + help
> + This feature allows mismatched rw semaphore locks and unlocks
> + to be detected and reported.
> +
Makes sense - but this should also be integrated into the rest of lock
debugging
Kconfig hierarchy similar to DEBUG_MUTEXES: i.e. DEBUG_LOCK_ALLOC,
PROVE_LOCKING,
etc. should select this new lock debugging option as well.
People generally are not supposed to know and configure the finer details,
CONFIG_LOCK_DEBUGGING=y is a one-stop-shop in this regard.
Thanks,
Ingo
