From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752505AbdKHL6p (ORCPT ); Wed, 8 Nov 2017 06:58:45 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:54732 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752211AbdKHL6o (ORCPT ); Wed, 8 Nov 2017 06:58:44 -0500 To: clingutla@codeaurora.org, kimran@codeaurora.org Cc: mingo@kernel.org, peterz@infradead.org, mcgrof@kernel.org, keescook@chromium.org, shile.zhang@nokia.com, matt@codeblueprint.co.uk, akpm@linux-foundation.org, vegard.nossum@oracle.com, jsiddle@redhat.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC] hung task: check specific tasks for long uninterruptible sleep state From: Tetsuo Handa References: <1503311156-16919-1-git-send-email-kimran@codeaurora.org> <20171108062813.25240-1-clingutla@codeaurora.org> In-Reply-To: <20171108062813.25240-1-clingutla@codeaurora.org> Message-Id: <201711082057.IDF56726.OMHOSFVFJtQOFL@I-love.SAKURA.ne.jp> X-Mailer: Winbiff [Version 2.51 PL2] X-Accept-Language: ja,en,zh Date: Wed, 8 Nov 2017 20:57:42 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Lingutla Chandrasekhar wrote: > Some tasks may intentionally moves to uninterruptable sleep state, > which shouldn't leads to khungtask panics, as those are recoverable > hungs. So to avoid false hung reports, add an option to select tasks > to be monitored and report/panic them only. What are backtraces of such tasks? Please point the locations in the code. If they are absolutely recoverable, why can't we let themselves declare that "I'm intentionally in uninterruptible state. But there is no dependency that prevents me from recovering. So, please ignore me." using per "struct task_struct" flags rather than introducing userspace controlled interface?