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

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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>
This commit is contained in:
Bart Van Assche 2019-02-14 15:00:44 -08:00 committed by Ingo Molnar
parent 956f3563a8
commit cdc84d7949
3 changed files with 13 additions and 0 deletions
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5
include/linux/lockdep.h
View File

@ -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)

6
kernel/locking/lockdep.c
View File

@ -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:
*/

2
lib/locking-selftest.c
View File

@ -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;
}