[PATCH 1/1] lockdep: pass curr_inner to print_lock_invalid_wait_context

[PATCH 1/1] lockdep: pass curr_inner to print_lock_invalid_wait_context

[Chen Jun]

Same information (task_wait_context(curr)) is printed twice.
curr_inner in check_wait_context is what we need.

Signed-off-by: Chen Jun <chenjun102@huawei.com>
---
 kernel/locking/lockdep.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 81e87280513e..2eb9802df7b9 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4676,10 +4676,8 @@ static inline short task_wait_context(struct task_struct *curr)
 
 static int
 print_lock_invalid_wait_context(struct task_struct *curr,
-				struct held_lock *hlock)
+				struct held_lock *hlock, short curr_inner)
 {
-	short curr_inner;
-
 	if (!debug_locks_off())
 		return 0;
 	if (debug_locks_silent)
@@ -4695,9 +4693,7 @@ print_lock_invalid_wait_context(struct task_struct *curr,
 	print_lock(hlock);
 
 	pr_warn("other info that might help us debug this:\n");
-
-	curr_inner = task_wait_context(curr);
-	pr_warn("context-{%d:%d}\n", curr_inner, curr_inner);
+	pr_warn("context-{%d:%d}\n", curr_inner, task_wait_context(curr));
 
 	lockdep_print_held_locks(curr);
 
@@ -4763,7 +4759,7 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
 	}
 
 	if (next_outer > curr_inner)
-		return print_lock_invalid_wait_context(curr, next);
+		return print_lock_invalid_wait_context(curr, next, curr_inner);
 
 	return 0;
 }
-- 
2.17.1

Re: [PATCH 1/1] lockdep: pass curr_inner to print_lock_invalid_wait_context

[Peter Zijlstra]

On Thu, Jun 16, 2022 at 01:40:42PM +0000, Chen Jun wrote:
> Same information (task_wait_context(curr)) is printed twice.

Yes, because at that point the inner and outer context are the same.

> curr_inner in check_wait_context is what we need.

IIRC it simply prints the task_wait_context as a starting point, the
lockdep_print_held_locks() should include the contexts for each of
those, after which you can compute the resulting value.

IOW, the information is complete.

Re: [PATCH 1/1] lockdep: pass curr_inner to print_lock_invalid_wait_context

[chenjun (AM)]

在 2022/6/17 21:22, Peter Zijlstra 写道:
> On Thu, Jun 16, 2022 at 01:40:42PM +0000, Chen Jun wrote:
>> Same information (task_wait_context(curr)) is printed twice.
> 
> Yes, because at that point the inner and outer context are the same.
> 
>> curr_inner in check_wait_context is what we need.
> 
> IIRC it simply prints the task_wait_context as a starting point, the
> lockdep_print_held_locks() should include the contexts for each of
> those, after which you can compute the resulting value.
> 
> IOW, the information is complete.
> 
> 
> 

Thanks for pointing this out.

-- 
Regards
Chen Jun