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Commit cdc84d79 authored by Bart Van Assche's avatar Bart Van Assche Committed by Ingo Molnar
Browse files

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: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent 956f3563

include/linux/lockdep.h

+5 −0
Original line number Diff line number Diff line
@@ -265,6 +265,7 @@ extern void lockdep_reset(void); 
extern void lockdep_reset_lock(struct lockdep_map *lock);

extern void lockdep_free_key_range(void *start, unsigned long size);

extern asmlinkage void lockdep_sys_exit(void);

extern void lockdep_set_selftest_task(struct task_struct *task);



extern void lockdep_off(void);

extern void lockdep_on(void);
@@ -395,6 +396,10 @@ static inline void lockdep_on(void) 
{

}



static inline void lockdep_set_selftest_task(struct task_struct *task)

{

}



# define lock_acquire(l, s, t, r, c, n, i)	do { } while (0)

# define lock_release(l, n, i)			do { } while (0)

# define lock_downgrade(l, i)			do { } while (0)

kernel/locking/lockdep.c

+6 −0
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ module_param(lock_stat, int, 0644); 
 * code to recurse back into the lockdep code...

 */

static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;

static struct task_struct *lockdep_selftest_task_struct;



static int graph_lock(void)

{
@@ -331,6 +332,11 @@ void lockdep_on(void) 
}

EXPORT_SYMBOL(lockdep_on);



void lockdep_set_selftest_task(struct task_struct *task)

{

	lockdep_selftest_task_struct = task;

}



/*

 * Debugging switches:

 */

lib/locking-selftest.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

}