From cdc84d794947b5431c0a6916c303aee7114819d2 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 14 Feb 2019 15:00:44 -0800 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Johannes Berg Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Waiman Long Cc: Will Deacon 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 --- include/linux/lockdep.h | 5 +++++ kernel/locking/lockdep.c | 6 ++++++ lib/locking-selftest.c | 2 ++ 3 files changed, 13 insertions(+) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index b5e6bfe0ae4a..66eee1ba0f2a 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -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) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 2d4c21a02546..34cd87c65f5d 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -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: */ 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; }