Re: [PATCH v7 1/2] hung_task: Reset warning budget when problem gets resolved

On Wed, Aug 05, 2026 at 12:40:10AM +0800, Lance Yang wrote:
> 
> On Tue, Aug 04, 2026 at 11:54:05AM -0400, Aaron Tomlin wrote:
> >From: Petr Mladek <[email protected]>
> >
> >sysctl_hung_task_warnings counts how many hung tasks are reported.
> >The watchdog does not report anything once the limit is reached.
> >Currently, this budget is decremented permanently, meaning the kernel is
> >left blind to subsequent hung tasks even after the original issue resolves.
> >
> >Keep the global sysctl_hung_task_warnings intact, and instead decrement
> >a copy (hung_task_warnings_printed) when warnings are printed. Reset
> >the copy back to the configured sysctl_hung_task_warnings limit once the
> >problem on the system gets resolved and check_hung_uninterruptible_tasks()
> >detects no hung tasks in a check interval.
> >
> >Also keep the copy updated when the global sysctl_hung_task_warnings
> >value is updated via sysctl, and update documentation to reflect
> >the new behavior.
> 
> I'd go with something like:
> 
> "
> hung_task: separate warning limit from runtime budget
> 
> sysctl_hung_task_warnings currently holds both the configured warning
> limit and the remaining budget. Each detailed report decrements the
> sysctl, so once it reaches zero, the configured limit is lost and cannot
> be restored automatically.
> 
> Keep sysctl_hung_task_warnings unchanged and track the remaining budget
> in hung_task_warnings_printed. Reset the runtime budget when a watchdog
> check sees no hung tasks or when userspace writes a new sysctl value.
> "
> 
> [...]
> 
> Cheers, Lance

Acknowledged.

-- 
Aaron Tomlin