From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42FC8EB64DC for ; Thu, 29 Jun 2023 10:01:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232190AbjF2KBw (ORCPT ); Thu, 29 Jun 2023 06:01:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232224AbjF2J7j (ORCPT ); Thu, 29 Jun 2023 05:59:39 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B1F73AA1; Thu, 29 Jun 2023 02:57:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D24886150B; Thu, 29 Jun 2023 09:57:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38882C433C8; Thu, 29 Jun 2023 09:57:17 +0000 (UTC) Date: Thu, 29 Jun 2023 10:57:14 +0100 From: Catalin Marinas To: Peter Collingbourne Cc: Will Deacon , akpm@linux-foundation.org, Qun-wei Lin =?utf-8?B?KOael+e+pOW0tCk=?= , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "surenb@google.com" , "david@redhat.com" , Chinwen Chang =?utf-8?B?KOW8temMpuaWhyk=?= , "kasan-dev@googlegroups.com" , Kuan-Ying Lee =?utf-8?B?KOadjuWGoOepjik=?= , Casper Li =?utf-8?B?KOadjuS4reamrik=?= , "gregkh@linuxfoundation.org" , vincenzo.frascino@arm.com, Alexandru Elisei , eugenis@google.com, Steven Price , stable@vger.kernel.org Subject: Re: [PATCH v4 1/3] mm: Call arch_swap_restore() from do_swap_page() Message-ID: References: <20230523004312.1807357-1-pcc@google.com> <20230523004312.1807357-2-pcc@google.com> <20230605140554.GC21212@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 05, 2023 at 10:41:12AM -0700, Peter Collingbourne wrote: > On Mon, Jun 5, 2023 at 7:06 AM Will Deacon wrote: > > On Mon, May 22, 2023 at 05:43:08PM -0700, Peter Collingbourne wrote: > > > Commit c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") moved > > > the call to swap_free() before the call to set_pte_at(), which meant that > > > the MTE tags could end up being freed before set_pte_at() had a chance > > > to restore them. Fix it by adding a call to the arch_swap_restore() hook > > > before the call to swap_free(). > > > > > > Signed-off-by: Peter Collingbourne > > > Link: https://linux-review.googlesource.com/id/I6470efa669e8bd2f841049b8c61020c510678965 > > > Cc: # 6.1 > > > Fixes: c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") > > > Reported-by: Qun-wei Lin (林群崴) > > > Closes: https://lore.kernel.org/all/5050805753ac469e8d727c797c2218a9d780d434.camel@mediatek.com/ > > > Acked-by: David Hildenbrand > > > Acked-by: "Huang, Ying" > > > Reviewed-by: Steven Price > > > Acked-by: Catalin Marinas > > > --- > > > v2: > > > - Call arch_swap_restore() directly instead of via arch_do_swap_page() > > > > > > mm/memory.c | 7 +++++++ > > > 1 file changed, 7 insertions(+) > > > > > > diff --git a/mm/memory.c b/mm/memory.c > > > index f69fbc251198..fc25764016b3 100644 > > > --- a/mm/memory.c > > > +++ b/mm/memory.c > > > @@ -3932,6 +3932,13 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > > > } > > > } > > > > > > + /* > > > + * Some architectures may have to restore extra metadata to the page > > > + * when reading from swap. This metadata may be indexed by swap entry > > > + * so this must be called before swap_free(). > > > + */ > > > + arch_swap_restore(entry, folio); > > > + > > > /* > > > * Remove the swap entry and conditionally try to free up the swapcache. > > > * We're already holding a reference on the page but haven't mapped it > > > > It looks like the intention is for this patch to land in 6.4, whereas the > > other two in the series could go in later, right? If so, I was expecting > > Andrew to pick this one up but he's not actually on CC. I've added him now, > > but you may want to send this as a separate fix so it's obvious what needs > > picking up for this cycle. > > I was expecting that this whole series could be picked up in mm. There > was a previous attempt to apply v3 of this series to mm, but that > failed because a dependent patch (commit c4c597f1b367 ("arm64: mte: Do > not set PG_mte_tagged if tags were not initialized")) hadn't been > merged into Linus's master branch yet. The series should be good to go > in now that that patch has been merged. Did this series fall through the cracks? I can't see it in linux-next (or maybe my grep'ing failed). The commit mentioned above is in 6.4-rc3 AFAICT. Unfortunately Andrew was not cc'ed on the initial post, Will added him later, so he likely missed it. For reference, the series is here: https://lore.kernel.org/r/20230523004312.1807357-1-pcc@google.com/ Andrew, what's your preference for this series? I'd like at least the first patch to go into 6.5 as a fix. The second patch seems to be fairly low risk and I'm happy for the third arm64 patch/cleanup to go in 6.5-rc1 (but it depends on the second patch). If you prefer, I can pick them up and send a pull request to Linus next week before -rc1. Otherwise you (or I) can queue the first patch and leave the other two for 6.6. Thanks. -- Catalin