Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:56012 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753008AbbFFVRt (ORCPT ); Sat, 6 Jun 2015 17:17:49 -0400 Date: Sat, 6 Jun 2015 23:16:48 +0200 From: Oleg Nesterov To: Petr Mladek Cc: Andrew Morton , Tejun Heo , Ingo Molnar , Peter Zijlstra , Richard Weinberger , Steven Rostedt , David Woodhouse , linux-mtd@lists.infradead.org, Trond Myklebust , Anna Schumaker , linux-nfs@vger.kernel.org, Chris Mason , "Paul E. McKenney" , Thomas Gleixner , Linus Torvalds , Jiri Kosina , Borislav Petkov , Michal Hocko , live-patching@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 11/18] jffs2: Convert jffs2_gcd_mtd kthread into the iterant API Message-ID: <20150606211648.GA15591@redhat.com> References: <1433516477-5153-1-git-send-email-pmladek@suse.cz> <1433516477-5153-12-git-send-email-pmladek@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1433516477-5153-12-git-send-email-pmladek@suse.cz> Sender: linux-nfs-owner@vger.kernel.org List-ID: On 06/05, Petr Mladek wrote: > > [*] In fact, there was a bug in the original code. It tried to process > a non-existing signal when the system was freezing. See the common > check for pending signal and freezing. And another bug afaics: > - case SIGSTOP: > - jffs2_dbg(1, "%s(): SIGSTOP received\n", > - __func__); > - set_current_state(TASK_STOPPED); > - schedule(); > - break; This is obviously racy, we can miss SIGCONT. Still I personally dislike the new kthread_sigaction() API. I agree, a couple if signal helpers for kthreads make sense. Say, void kthread_do_signal_stop(void) { spin_lock_irq(&curtent->sighand->siglock); if (current->jobctl & JOBCTL_STOP_DEQUEUED) __set_current_state(TASK_STOPPED); spin_unlock_irq(¤t->sighand->siglock); schedule(); } and probably even "int kthread_signal_deque(void)". But personally I do not think kthread_do_signal() makes a lot of sense... Oleg.