From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f43.google.com ([74.125.82.43]:54622 "EHLO mail-wm0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728137AbeGTL5n (ORCPT ); Fri, 20 Jul 2018 07:57:43 -0400 Received: by mail-wm0-f43.google.com with SMTP id c14-v6so9131865wmb.4 for ; Fri, 20 Jul 2018 04:09:57 -0700 (PDT) Subject: Re: request for 4.14-stable: 1dc3039bc87a ("block: do not use interruptible wait anywhere") To: Sudip Mukherjee Cc: Greg Kroah-Hartman , stable@vger.kernel.org References: <20180719220936.wala6fa7st6q3xok@debian> <5f24dbd5-3c1d-9cab-eeca-467a4dd38a2d@gmail.com> <20180720102619.6ek7cntouhotgd33@debian> From: Alan Jenkins Message-ID: <14cf6af0-5b2c-5b5d-2b5d-2505bbd4d505@gmail.com> Date: Fri, 20 Jul 2018 12:09:54 +0100 MIME-Version: 1.0 In-Reply-To: <20180720102619.6ek7cntouhotgd33@debian> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-GB Sender: stable-owner@vger.kernel.org List-ID: On 20/07/18 11:26, Sudip Mukherjee wrote: > Hi Alan, > My thought was that since you said "or" in your commit message: > "When blk_queue_enter() waits for a queue to unfreeze, or unset the > PREEMPT_ONLY flag, do not allow it to be interrupted by a signal", so > the fault condition can be when it is waiting on the queue and is > interrupted. So even though 'PREEMPT_ONLY' is not there in v4.14.y, we > can see the problem just because of getting interrupted while on queue. > > Plesase correct me if I was wrong. You're absolutely right. I suppose the original commit message might not be quite as clear when added in 4.14.x, so I had biased against that a bit. pre-v4.15 doesn't fail the suspend test in the commit message, but a test was added to blktests afterwards, which should exactly cover the "or" part. https://github.com/osandov/blktests/blob/master/tests/block/016 >> IIUC, the bugfix could be applied to *three* of the "longterm" kernel lines: >> 4.14.56, 4.9.113, 4.4.142.  Since the commit says this bug was introduced to >> the single-queue block layer in v4.4, commit 3ef28e8 ("block: generic >> request_queue reference counting"). > I will send the backport for v4.9.y and v4.4.y also.