[tip:locking/core] locking/lockdep: Print the right depth for chain key collision

[tip-bot for Yuyang Du <tipbot@zytor.com>]

Commit-ID:  834494b28024b39d45aea6bcc642b0fe94fe2503
Gitweb:     https://git.kernel.org/tip/834494b28024b39d45aea6bcc642b0fe94fe2503
Author:     Yuyang Du <duyuyang@gmail.com>
AuthorDate: Mon, 6 May 2019 16:19:21 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 3 Jun 2019 11:55:36 +0200

locking/lockdep: Print the right depth for chain key collision

Since chains are separated by IRQ context, so when printing a chain the
depth should be consistent with it.

Signed-off-by: Yuyang Du <duyuyang@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bvanassche@acm.org
Cc: frederic@kernel.org
Cc: ming.lei@redhat.com
Cc: will.deacon@arm.com
Link: https://lkml.kernel.org/r/20190506081939.74287-6-duyuyang@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/locking/lockdep.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 3c477018e184..bc1efc12a8c5 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2519,10 +2519,11 @@ print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_ne
 	struct held_lock *hlock;
 	u64 chain_key = 0;
 	int depth = curr->lockdep_depth;
-	int i;
+	int i = get_first_held_lock(curr, hlock_next);
 
-	printk("depth: %u\n", depth + 1);
-	for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) {
+	printk("depth: %u (irq_context %u)\n", depth - i + 1,
+		hlock_next->irq_context);
+	for (; i < depth; i++) {
 		hlock = curr->held_locks + i;
 		chain_key = print_chain_key_iteration(hlock->class_idx, chain_key);