From mboxrd@z Thu Jan 1 00:00:00 1970 From: Artem Savkov Subject: Re: [PATCH] thinkpad-acpi: fix potential suspend blocking issue Date: Thu, 7 Mar 2013 00:18:49 +0400 Message-ID: <20130306201849.GA4897@thinkpad.lan> References: <201303042055.38040.maciej.rutecki@gmail.com> <1362504883-9180-1-git-send-email-msb@chromium.org> <20130305141817.4e27e83aa66598115e52eb9e@linux-foundation.org> <20130306155039.GB7697@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20130306155039.GB7697@redhat.com> Sender: platform-driver-x86-owner@vger.kernel.org To: Oleg Nesterov Cc: Andrew Morton , Mandeep Singh Baines , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, ibm-acpi@hmh.eng.br, ibm-acpi-devel@lists.sourceforge.net, platform-driver-x86@vger.kernel.org, Aaron Lu , Henrique de Moraes Holschuh , Tejun Heo , Maciej Rutecki List-Id: linux-acpi@vger.kernel.org On Wed, Mar 06, 2013 at 04:50:39PM +0100, Oleg Nesterov wrote: > On 03/05, Andrew Morton wrote: > > > > Basically the same as > > http://ozlabs.org/~akpm/mmots/broken-out/drivers-platform-x86-thinkpad_acpic-move-hotkey_thread_mutex-lock-after-set_freezable.patch. > > I think Artem's patch is a little better. There doesn't appear to be > > any locking protocol for tpacpi_lifecycle. > > Which seems to have the same problem, hotkey_kthread() still calls > kthread_freezable_should_stop() under hotkey_thread_mutex. > > IOW, we have two try_to_freeze's here, the patch moves only one of > them outside of the hotkey_thread_mutex. It's hard for me to judge but this lock does indeed look like it has been used to block until the thread exits. I'm trying out the "remove hotkey_thread_mutex completely" approach and everything looks fine so far. -- Regards, Artem