[PATCH] lockdep: Fix wrong condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS

[PATCH] lockdep: Fix wrong condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS

[Byungchul Park]

Bug messages and stack dump for MAX_LOCKDEP_CHAIN_HLOCKS should be
printed only at the first time.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 kernel/locking/lockdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index f37156f..a143eb4 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2166,7 +2166,7 @@ static inline int add_chain_cache(struct task_struct *curr,
 	 * Important for check_no_collision().
 	 */
 	if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) {
-		if (debug_locks_off_graph_unlock())
+		if (!debug_locks_off_graph_unlock())
 			return 0;
 
 		print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
-- 
1.9.1

Re: [PATCH] lockdep: Fix wrong condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS

[Byungchul Park]

On Fri, Jan 13, 2017 at 11:42:04AM +0900, Byungchul Park wrote:
> Bug messages and stack dump for MAX_LOCKDEP_CHAIN_HLOCKS should be
> printed only at the first time.

Could you tell me what you think? Am I wrong?

> 
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> ---
>  kernel/locking/lockdep.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index f37156f..a143eb4 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -2166,7 +2166,7 @@ static inline int add_chain_cache(struct task_struct *curr,
>  	 * Important for check_no_collision().
>  	 */
>  	if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) {
> -		if (debug_locks_off_graph_unlock())
> +		if (!debug_locks_off_graph_unlock())
>  			return 0;
>  
>  		print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
> -- 
> 1.9.1

Re: [PATCH] lockdep: Fix wrong condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS

[Peter Zijlstra]

On Fri, Jan 13, 2017 at 11:42:04AM +0900, Byungchul Park wrote:
> Bug messages and stack dump for MAX_LOCKDEP_CHAIN_HLOCKS should be
> printed only at the first time.
> 
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>

Indeed, thanks!

> ---
>  kernel/locking/lockdep.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index f37156f..a143eb4 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -2166,7 +2166,7 @@ static inline int add_chain_cache(struct task_struct *curr,
>  	 * Important for check_no_collision().
>  	 */
>  	if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) {
> -		if (debug_locks_off_graph_unlock())
> +		if (!debug_locks_off_graph_unlock())
>  			return 0;
>  
>  		print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
> -- 
> 1.9.1
> 

[tip:locking/core] lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS

[tip-bot for Byungchul Park]

Commit-ID:  f9af456a61ecfbef8233c5046a9e347c9b98ba05
Gitweb:     http://git.kernel.org/tip/f9af456a61ecfbef8233c5046a9e347c9b98ba05
Author:     Byungchul Park <byungchul.park@lge.com>
AuthorDate: Fri, 13 Jan 2017 11:42:04 +0900
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 10 Feb 2017 09:09:48 +0100

lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS

Bug messages and stack dump for MAX_LOCKDEP_CHAIN_HLOCKS should only
be printed once.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1484275324-28192-1-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/locking/lockdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 7c38f8f..bf60725 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2203,7 +2203,7 @@ cache_hit:
 	 * Important for check_no_collision().
 	 */
 	if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) {
-		if (debug_locks_off_graph_unlock())
+		if (!debug_locks_off_graph_unlock())
 			return 0;
 
 		print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");