The following commit has been merged into the locking/urgent branch of tip:
Commit-ID: 1a39340865ce505a029b37aeb47a3e4c8db5f6c6 Gitweb: https://git.kernel.org/tip/1a39340865ce505a029b37aeb47a3e4c8db5f6c6 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Tue, 27 Oct 2020 13:48:34 +01:00 Committer: Peter Zijlstra <pet...@infradead.org> CommitterDate: Fri, 30 Oct 2020 17:07:18 +01:00 lockdep: Fix nr_unused_locks accounting Chris reported that commit 24d5a3bffef1 ("lockdep: Fix usage_traceoverflow") breaks the nr_unused_locks validation code triggered by /proc/lockdep_stats. By fully splitting LOCK_USED and LOCK_USED_READ it becomes a bad indicator for accounting nr_unused_locks; simplyfy by using any first bit. Fixes: 24d5a3bffef1 ("lockdep: Fix usage_traceoverflow") Reported-by: Chris Wilson <ch...@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Tested-by: Chris Wilson <ch...@chris-wilson.co.uk> Link: https://lkml.kernel.org/r/20201027124834.gl2...@hirez.programming.kicks-ass.net --- kernel/locking/lockdep.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 1102849..b71ad8d 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4396,6 +4396,9 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, if (unlikely(hlock_class(this)->usage_mask & new_mask)) goto unlock; + if (!hlock_class(this)->usage_mask) + debug_atomic_dec(nr_unused_locks); + hlock_class(this)->usage_mask |= new_mask; if (new_bit < LOCK_TRACE_STATES) { @@ -4403,19 +4406,10 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, return 0; } - switch (new_bit) { - case 0 ... LOCK_USED-1: + if (new_bit < LOCK_USED) { ret = mark_lock_irq(curr, this, new_bit); if (!ret) return 0; - break; - - case LOCK_USED: - debug_atomic_dec(nr_unused_locks); - break; - - default: - break; } unlock:
