[ Upstream commit 68d41d8c94a31dfb8233ab90b9baf41a2ed2da68 ]
The stats variable nr_unused_locks is incremented every time a new lock
class is register and decremented when the lock is first used in
__lock_acquire(). And after all, it is shown and checked in lockdep_stats.
However, under configurations that either CONFIG_TRACE_IRQFLAGS or
CONFIG_PROVE_LOCKING is not defined:
The commit:
091806515124b20 ("locking/lockdep: Consolidate lock usage bit initialization")
missed marking the LOCK_USED flag at IRQ usage initialization because
as mark_usage() is not called. And the commit:
886532aee3cd42d ("locking/lockdep: Move mark_lock() inside
CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING")
further made mark_lock() not defined such that the LOCK_USED cannot be
marked at all when the lock is first acquired.
As a result, we fix this by not showing and checking the stats under such
configurations for lockdep_stats.
Reported-by: Qian Cai <c...@lca.pw>
Signed-off-by: Yuyang Du <duyuy...@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Will Deacon <will.dea...@arm.com>
Cc: a...@arndb.de
Cc: frede...@kernel.org
Link: https://lkml.kernel.org/r/20190709101522.9117-1-duyuy...@gmail.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
kernel/locking/lockdep_proc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index dbb61a302548..9778b6701019 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -227,6 +227,7 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
sum_forward_deps = 0;
+#ifdef CONFIG_PROVE_LOCKING
list_for_each_entry(class, &all_lock_classes, lock_entry) {
if (class->usage_mask == 0)
@@ -258,12 +259,12 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
nr_hardirq_read_unsafe++;
-#ifdef CONFIG_PROVE_LOCKING
sum_forward_deps += lockdep_count_forward_deps(class);
-#endif
}
#ifdef CONFIG_DEBUG_LOCKDEP
DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
+#endif
+
#endif
seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
nr_lock_classes, MAX_LOCKDEP_KEYS);
--
2.20.1
