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| author | Yuyang Du <duyuyang@gmail.com> | 2019-07-09 13:15:22 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-07-13 12:24:53 +0300 |
| commit | 68d41d8c94a31dfb8233ab90b9baf41a2ed2da68 (patch) | |
| tree | 4f57eca5c312139e1ac9ce039a412e0920838e89 /kernel/locking | |
| parent | f632a8170a6b667ee4e3f552087588f0fe13c4bb (diff) | |
| download | linux-68d41d8c94a31dfb8233ab90b9baf41a2ed2da68.tar.xz | |
locking/lockdep: Fix lock used or unused stats error
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 <cai@lca.pw>
Signed-off-by: Yuyang Du <duyuyang@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
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: Will Deacon <will.deacon@arm.com>
Cc: arnd@arndb.de
Cc: frederic@kernel.org
Link: https://lkml.kernel.org/r/20190709101522.9117-1-duyuyang@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep_proc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 9c49ec645d8b..65b6a1600c8f 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -210,6 +210,7 @@ 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) @@ -241,13 +242,13 @@ 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); seq_printf(m, " direct dependencies: %11lu [max: %lu]\n", |