locking/rwsem: Add DEBUG_RWSEMS to look for lock/unlock mismatches
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.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1522445280-7767-2-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 64155e3..88650ab 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1075,6 +1075,13 @@
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 debugging feature allows mismatched rw semaphore locks and unlocks
+ to be detected and reported.
+
config DEBUG_LOCK_ALLOC
bool "Lock debugging: detect incorrect freeing of live locks"
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
@@ -1097,6 +1104,7 @@
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
+ select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
select DEBUG_LOCK_ALLOC
select TRACE_IRQFLAGS
default n
