Re: [PATCH v8 0/2] hung_task: Improve warning budget handling and task reporting
Andrew Morton <[email protected]>
| Newsgroups | org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On Tue, 4 Aug 2026 16:20:48 -0400 Aaron Tomlin <[email protected]> wrote: > The hung_task watchdog detects tasks stuck in TASK_UNINTERRUPTIBLE (D) > state for longer than CONFIG_DEFAULT_HUNG_TASK_TIMEOUT seconds. To prevent > log spam during system spikes, sysctl_hung_task_warnings enforces a budget > on the number of logged warnings. > > However, the current implementation has two major limitations: > > 1. Permanent exhaustion of warning budget > > sysctl_hung_task_warnings is decremented directly when printing > warnings. Once this budget hits zero, no further warnings are > reported until an administrator manually updates the sysctl value or > reboots the system. Consequently, a single temporary hang episode > permanently blinds the kernel watchdog to any subsequent hung tasks > after system recovery. > > 2. Total log suppression when budget is exhausted > > Once the warning budget reaches zero, hung_task_info() completely > suppresses all output, including the basic single-line alert. While > suppressing verbose stack dumps and lock debugging is desirable to > prevent dmesg flooding, hiding basic task alerts leaves > administrators entirely unaware that tasks are hanging. > > This patch series resolves both limitations by decoupling the configured > warning budget from the runtime warning counter, automatically resetting > the budget when the system recovers, and keeping basic single-line hung > task alerts visible. Thanks. A couple of concerns from AI review: https://sashiko.dev/#/patchset/[email protected] Apologies if these were considered during review of previous iterations.