From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id 2BF546B0038 for ; Tue, 6 Sep 2016 20:45:23 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id 44so736455qtf.3 for ; Tue, 06 Sep 2016 17:45:23 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id j197si3679962ybj.315.2016.09.06.17.45.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 06 Sep 2016 17:45:22 -0700 (PDT) Message-ID: <1473209119.32433.174.camel@redhat.com> Subject: Re: [PATCH] mm:Avoid soft lockup due to possible attempt of double locking object's lock in __delete_object From: Rik van Riel Date: Tue, 06 Sep 2016 20:45:19 -0400 In-Reply-To: References: <1472582112-9059-1-git-send-email-xerofoify@gmail.com> <20160831075421.GA15732@e104818-lin.cambridge.arm.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-eCegwyLach2nn8zbkR2h" Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: nick , Catalin Marinas Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org --=-eCegwyLach2nn8zbkR2h Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2016-08-31 at 09:24 -0400, nick wrote: >=20 > On 2016-08-31 03:54 AM, Catalin Marinas wrote: > > On Tue, Aug 30, 2016 at 02:35:12PM -0400, Nicholas Krause wrote: > > > This fixes a issue in the current locking logic of the function, > > > __delete_object where we are trying to attempt to lock the passed > > > object structure's spinlock again after being previously held > > > elsewhere by the kmemleak code. Fix this by instead of assuming > > > we are the only one contending for the object's lock their are > > > possible other users and create two branches, one where we get > > > the lock when calling spin_trylock_irqsave on the object's lock > > > and the other when the lock is held else where by kmemleak. > >=20 > > Have you actually got a deadlock that requires this fix? > >=20 > Yes I have got a deadlock that this does fix. Why don't you share the backtrace with us? Claiming you have a deadlock, but not sharing it on the list means nobody can see what the problem is you are trying to address. It would be good if every email with a patch that you post starts with an actual detailed problem description. Can you do that? --=20 All Rights Reversed. --=-eCegwyLach2nn8zbkR2h Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABCAAGBQJXz2MfAAoJEM553pKExN6DxSEH/iEY6vsZa6T3kRb3T9yCDzG0 Vc+5o/9OkAKca4y+dfRfK17rYpRIwfAhhzAgFqxKXO68Hbg+MRIR7nvLbyou7HN9 lCFzsjROgIIBsjA7qp6K6qAD7vUheVxkEw67DJ/gdiZZMd+ZEjwJMAMtXI9T0lPD RsofczPuR933m3i8NaLucvK+W6AqDUgeJ0mLKiL4TBMoWPFQ72rqk06GmIr87T4u 7hNz4EaFFGj5C8f54/r44ZqTZt7o+h2A4KUrMs+4DbIAyYk7P31lk0S425wVXuBt NRCreghupr+lV7xtOwb2xSEGGXbgTJX0HbTfg96+UEycCAyyeHCpBpgiuaP7ARs= =eNlz -----END PGP SIGNATURE----- --=-eCegwyLach2nn8zbkR2h-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org