locking/lockdep: Make it easy to detect whether or not inside a selftest

The patch that frees unused lock classes will modify the behavior of
lockdep_free_key_range() and lockdep_reset_lock() depending on whether
or not these functions are called from the context of the lockdep
selftests. Hence make it easy to detect whether or not lockdep code
is called from the context of a lockdep selftest.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
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>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20190214230058.196511-10-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 1e1bbf171eca..a1705545e6ac 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -1989,6 +1989,7 @@ void locking_selftest(void)
 
         init_shared_classes();
         debug_locks_silent = !debug_locks_verbose;
+        lockdep_set_selftest_task(current);
 
         DO_TESTCASE_6R("A-A deadlock", AA);
         DO_TESTCASE_6R("A-B-B-A deadlock", ABBA);
@@ -2097,5 +2098,6 @@ void locking_selftest(void)
                 printk("---------------------------------\n");
                 debug_locks = 1;
         }
+        lockdep_set_selftest_task(NULL);
         debug_locks_silent = 0;
 }