Messages in this thread | | | Date | Tue, 27 Mar 2018 08:06:55 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v2] locking/rwsem: Add DEBUG_RWSEMS to look for lock/unlock mismatches |
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* Waiman Long <longman@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
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