[PATCH] hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help

[PATCH] hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help

[Xibo Wang]

The help text still says the feature only covers mutexes, but blocker
tracking has since been extended to semaphores and rwsems. Update the
description to match the supported lock types.

Signed-off-by: Xibo Wang <wangxb12@chinatelecom.cn>
---
 lib/Kconfig.debug | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1244dcac2294..c2ffaff918d1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1320,10 +1320,11 @@ config DETECT_HUNG_TASK_BLOCKER
 	depends on !PREEMPT_RT
 	default y
 	help
-	  Say Y here to show the blocker task's stacktrace who acquires
-	  the mutex lock which "hung tasks" are waiting.
-	  This will add overhead a bit but shows suspicious tasks and
-	  call trace if it comes from waiting a mutex.
+	  Say Y here to show the blocker task's stacktrace that holds
+	  the lock which "hung tasks" are waiting on. Supported lock
+	  types are mutex, semaphore, and rwsem.
+	  This will add a bit of overhead but shows suspicious tasks and
+	  call traces if it comes from waiting on one of these locks.
 
 config WQ_WATCHDOG
 	bool "Detect Workqueue Stalls"
-- 
2.46.0

Re: [PATCH] hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help

[Lance Yang]

+Cc Petr

get_maintainer.pl is your friend :) please use it next time.

On Thu, Jul 30, 2026 at 11:17:51AM +0800, Xibo Wang wrote:
>The help text still says the feature only covers mutexes, but blocker
>tracking has since been extended to semaphores and rwsems. Update the
>description to match the supported lock types.

Thanks!

>Signed-off-by: Xibo Wang <wangxb12@chinatelecom.cn>
>---
> lib/Kconfig.debug | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
>diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>index 1244dcac2294..c2ffaff918d1 100644
>--- a/lib/Kconfig.debug
>+++ b/lib/Kconfig.debug
>@@ -1320,10 +1320,11 @@ config DETECT_HUNG_TASK_BLOCKER
> 	depends on !PREEMPT_RT
> 	default y
> 	help
>-	  Say Y here to show the blocker task's stacktrace who acquires
>-	  the mutex lock which "hung tasks" are waiting.
>-	  This will add overhead a bit but shows suspicious tasks and
>-	  call trace if it comes from waiting a mutex.
>+	  Say Y here to show the blocker task's stacktrace that holds
>+	  the lock which "hung tasks" are waiting on. Supported lock
>+	  types are mutex, semaphore, and rwsem.
>+	  This will add a bit of overhead but shows suspicious tasks and
>+	  call traces if it comes from waiting on one of these locks.

"holds the lock" seems too strong here...

For semaphores we only have the last holder, and rwsem owner tracking is
best-effort for readers. So this is only a possible blocker, not
necessarily the current lock holder.

I'd rather go with:

	  Say Y here to show a possible blocker task's stacktrace when
	  a hung task is waiting on a mutex, semaphore, or rwsem.
	  This will add a bit of overhead but shows suspicious tasks and
	  call traces for waits on one of these locks.

Cheers, Lance

Re: [PATCH] hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help

[Xibo Wang]

Hi Lance,

On Thu, Jul 30, 2026 at 12:47:35PM +0800, Lance Yang wrote:
> +Cc Petr
> 
> get_maintainer.pl is your friend :) please use it next time.

Will do. Sorry for missing it.

> "holds the lock" seems too strong here...
> 
> For semaphores we only have the last holder, and rwsem owner tracking is
> best-effort for readers. So this is only a possible blocker, not necessarily
> the current lock holder.

Agreed, that's a fair point. I'll adopt your suggested wording and also
Cc Petr in v2.

Thanks,
Xibo

[PATCH v2] hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help

[Xibo Wang]

The help text still says the feature only covers mutexes, but blocker
tracking has since been extended to semaphores and rwsems. Update the
description to match the supported lock types.

Cc: Petr Mladek <pmladek@suse.com>
Suggested-by: Lance Yang <lance.yang@linux.dev>
Signed-off-by: Xibo Wang <wangxb12@chinatelecom.cn>
---
 lib/Kconfig.debug | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1244dcac2294..718475d974bb 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1320,10 +1320,10 @@ config DETECT_HUNG_TASK_BLOCKER
 	depends on !PREEMPT_RT
 	default y
 	help
-	  Say Y here to show the blocker task's stacktrace who acquires
-	  the mutex lock which "hung tasks" are waiting.
-	  This will add overhead a bit but shows suspicious tasks and
-	  call trace if it comes from waiting a mutex.
+	  Say Y here to show a possible blocker task's stacktrace when
+	  a hung task is waiting on a mutex, semaphore, or rwsem.
+	  This will add a bit of overhead but shows suspicious tasks and
+	  call traces for waits on one of these locks.
 
 config WQ_WATCHDOG
 	bool "Detect Workqueue Stalls"
-- 
2.46.0

Re: [PATCH v2] hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help

[Lance Yang]

On 2026/7/30 14:18, Xibo Wang wrote:
> The help text still says the feature only covers mutexes, but blocker
> tracking has since been extended to semaphores and rwsems. Update the
> description to match the supported lock types.
> 
> Cc: Petr Mladek <pmladek@suse.com>
> Suggested-by: Lance Yang <lance.yang@linux.dev>
> Signed-off-by: Xibo Wang <wangxb12@chinatelecom.cn>
> ---

Thanks.

Reviewed-by: Lance Yang <lance.yang@linux.dev>