[PATCH 09/32] locking/lockdep: Save stack trace for each softirq vector involved

[Frederic Weisbecker]

We are going to save as much traces as we have softirq vectors involved
in a given usage. Expand the stack trace record code accordingly.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Pavan Kondeti <pkondeti@xxxxxxxxxxxxxx>
Cc: Paul E . McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: David S . Miller <davem@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
 include/linux/lockdep.h  |  3 ++-
 kernel/locking/lockdep.c | 18 +++++++++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 06669f20a30a..69d2dac3d821 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -31,8 +31,9 @@ extern int lock_stat;
 /*
  * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
  * the total number of states... :-(
+ * 1 bit for LOCK_USED, 4 bits for hardirqs and 4 * NR_SOFTIRQS bits
  */
-#define XXX_LOCK_USAGE_STATES		(1+2*4)
+#define XXX_LOCK_USAGE_STATES		(1 + (1 + 10) * 4)
 
 /*
  * NR_LOCKDEP_CACHING_CLASSES ... Number of classes
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 9194f11d3dfb..4bac8c1a3929 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3145,6 +3145,22 @@ static inline int separate_irq_context(struct task_struct *curr,
 
 #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
 
+static int save_trace_mask(struct lock_class *class, u64 mask)
+{
+	int bit = 0;
+
+	while (mask) {
+		long fs = __ffs64(mask) + 1;
+
+		mask >>= fs;
+		bit += fs;
+		if (!save_trace(class->usage_traces + bit - 1))
+			return -1;
+	}
+
+	return 0;
+}
+
 /*
  * Mark a lock with a usage bit, and validate the state transition:
  */
@@ -3172,7 +3188,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 
 	hlock_class(this)->usage_mask |= new_mask;
 
-	if (!save_trace(hlock_class(this)->usage_traces + new_usage->bit))
+	if (save_trace_mask(hlock_class(this), new_mask) < 0)
 		return 0;
 
 	switch (new_usage->bit) {
-- 
2.17.1