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| author |   Peter Zijlstra <peterz@infradead.org> | 2020-10-27 13:48:34 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-10-30 17:07:18 +0100 |
| commit | 1a39340865ce505a029b37aeb47a3e4c8db5f6c6 (patch) | |
| tree | 54c08eab491b2b6ded61b910db833389ff6a4679 /kernel/locking | |
| parent | locking/lockdep: Remove more raw_cpu_read() usage (diff) | |
| download | linux-dev-1a39340865ce505a029b37aeb47a3e4c8db5f6c6.tar.xz linux-dev-1a39340865ce505a029b37aeb47a3e4c8db5f6c6.zip | |
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 <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://lkml.kernel.org/r/20201027124834.GL2628@hirez.programming.kicks-ass.net
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 14 |
1 files changed, 4 insertions, 10 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 11028497d4df..b71ad8d9f1c9 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: |