From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19258379C32 for ; Tue, 4 Aug 2026 23:05:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785884757; cv=none; b=oCWv1+JRAlt5oDCz7IMROe22qvLOsUQku7viLABs+dptZsDa5XXlkJAtu2zy93U5+bmS83FahFQ1krO9GHdLV89AD9WjCWPip1OoXVeAXC3Yub/8ovnjrEoNOhu1UA7Lr3tyAmq4HIzrThOOeCKlwfZiZxSs+6ECfShHnh+Dcco= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785884757; c=relaxed/simple; bh=/KC8ORkG44Yc/BN601YwryXrDw84IARWM3DWiJpDfzE=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=fC1ucz6RcR7MifrofyHWUIHSEU9zWgcUe4QsjMTSqO3bPiqJR7APGuNAe9WAh+LxyPK9x+Xnq/wFYv7UpiGYwV8zez5BL6lDOPpc8kT3qg2M3zjrfz0gv/OJCvtahEME7iYcoRrVTl0u2CksSJxJdrN62/V1wR58mKvcRDDX6bM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Yf86hdqL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Yf86hdqL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68FB71F000E9; Tue, 4 Aug 2026 23:05:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1785884755; bh=qGuQUBaawqMNDqxsRmJaIKXtjOjDqf8fPs+PfElgTUY=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=Yf86hdqLQxFUNaCuZ/Rq9bnClnqeuOlJtzQmrJTeQxwsLklW+DR6LVaqMvOoscvSa 4szJjkW+dtJTmibJkcYpBRZ5CB28RXoYFv1tEY3w5pLvKY9yaXCUjFFahcVKnjI6Jc usUNV94Mg7WUF+GZHs47S3AwAGbuZatfcKhFSMFY= Date: Tue, 4 Aug 2026 16:05:55 -0700 From: Andrew Morton To: Aaron Tomlin Cc: lance.yang@linux.dev, mhiramat@kernel.org, pmladek@suse.com, linux-kernel@vger.kernel.org, david.laight.linux@gmail.com, neelx@suse.com, sean@ashe.io, chjohnst@gmail.com, steve@abita.co, mproche@gmail.com, nick.lange@gmail.com Subject: Re: [PATCH v8 0/2] hung_task: Improve warning budget handling and task reporting Message-Id: <20260804160555.7622850f6162aae463714289@linux-foundation.org> In-Reply-To: <20260804202050.262427-1-atomlin@atomlin.com> References: <20260804202050.262427-1-atomlin@atomlin.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 4 Aug 2026 16:20:48 -0400 Aaron Tomlin 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/20260804202050.262427-1-atomlin@atomlin.com Apologies if these were considered during review of previous iterations.