From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1B85606A338 for ; Tue, 27 Oct 2026 09:33:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=2Xgn9ee2; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=oKfzWY26 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=gIudMcxLM3PAXcDR9AP1Q8SoYHkkEJyeOudQMB7zZi4=; b=2Xgn9ee2ZqFxy17I9kg99cjhyy fS3cySr2m6rwWbZiQfHrqGgFHernzXMvhzaSlrWqXsHgqZW+xEqiExTev6Orae/uiUta6AZIEp7oi qcv1s4B6BAsCNvAYUTPB6MrS3B+r3cIskCIwTOjF1WsVIsRffhPZNjUARi1SOUDNjxoXL8zh0se+G 17LNRir7t1P3PNVQ2h02e175Avssk9Y7+x9A0Idb2OvwFn1nZ5MISLqmgkrkYxTiyNn562jELViF0 DUuIC6umFSv+d6eYG5gJYQAkyevhRIBHBy1t31p7YoZ92R7dZ7gLEatcjIurZdhjiFf/HqKvUjR2e 26h64wvw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLdZ0-00000004AfI-18h1; Tue, 27 Oct 2026 09:33:50 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLdYy-00000004Aey-3cIX for kexec@lists.infradead.org; Tue, 27 Oct 2026 09:33:48 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 0D5AC60136; Tue, 27 Oct 2026 09:33:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 095811F031E4; Tue, 27 Oct 2026 09:33:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793093627; bh=gIudMcxLM3PAXcDR9AP1Q8SoYHkkEJyeOudQMB7zZi4=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=oKfzWY26WKA+bbXl616ae0oQzbA1G0xH9l9xh1gCxq3JDpe8yv97IXYdyOfHQ4eJr t81Po39gxIf/641f8WvuMrH0lH9eqiO320Dz8AtVuz8iZU3projZTXWMccoEocNd/6 dh/GTbiarJBXfnd4LASC1pYnYHmLhWpnrmbzH4mHnkutHY5LYB08EzCW/mDgGMPsGa qOAll772fgvtDpz0InhCuO+wST7Gz+w1BkWkocfnh9yOov6hzmvFdgw6+D2H+bUwyj Zopnno5uue65TWC1px1FoMLDq3bw/n2ASl+8B3UapPHEfEcHiQNOqE7pRfjn9OD0/j SZDcHaIh8SkjQ== Date: Tue, 27 Oct 2026 09:33:31 +0000 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, Josef Bacik , stable@vger.kernel.org Subject: Re: [PATCH 27/46] mm/mmu_notifier: finish non-blocking interval invalidation on error Message-ID: References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-27-6f74bec9a5bb@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261027-fixes_core-v1-27-6f74bec9a5bb@kernel.org> X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" X-Spam-Status: No, score=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Oct 27, 2026 at 12:17:47AM +0100, David Hildenbrand (Arm) wrote: > From: Josef Bacik > > When an ordinary MMU notifier rejects a non-blocking invalidation, the > interval invalidation started beforehand is left unfinished: the caller > skips mmu_notifier_invalidate_range_end(). Subsequent interval notifier > operations can then wait forever. > > The only in-tree trigger is nouveau SVM, which uses both notifier types > and rejects non-blocking invalidations. Reaping via the OOM reaper or > process_mrelease() can therefore leave the GPU fault worker stuck, > holding a reference that prevents the dying process's address space > and memory from being freed. > > End the interval invalidation when an ordinary notifier fails a > non-blocking invalidation, like mn_itree_invalidate() already does when > an interval notifier fails. Make that handling clearer in the > documentation of mmu_notifier_invalidate_range_start_nonblock(). > > Fix generated by an LLM and sent by Josef Bacik in private. > > Fixes: 99cb252f5e68 ("mm/mmu_notifier: add an interval tree notifier") > Cc: stable@vger.kernel.org > Signed-off-by: Josef Bacik > [ david: simplify description, update function doc ] > Signed-off-by: David Hildenbrand (Arm) Acked-by: Lorenzo Stoakes (ARM) > --- > include/linux/mmu_notifier.h | 3 ++- > mm/mmu_notifier.c | 17 +++++++++++++---- > 2 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h > index a11a44eef521e..5db78e5761c5c 100644 > --- a/include/linux/mmu_notifier.h > +++ b/include/linux/mmu_notifier.h > @@ -483,7 +483,8 @@ mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range) > /* > * This version of mmu_notifier_invalidate_range_start() avoids blocking, but it > * can return an error if a notifier can't proceed without blocking, in which > - * case you're not allowed to modify PTEs in the specified range. > + * case you're not allowed to modify PTEs in the specified range or call > + * mmu_notifier_invalidate_range_end(). > * > * This is mainly intended for OOM handling. > */ > diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c > index df69ba6e797f7..2e20f88e162d7 100644 > --- a/mm/mmu_notifier.c > +++ b/mm/mmu_notifier.c > @@ -569,16 +569,25 @@ int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range) > { > struct mmu_notifier_subscriptions *subscriptions = > range->mm->notifier_subscriptions; > - int ret; > + const bool has_itree = subscriptions->has_itree; > + int ret = 0; > > - if (subscriptions->has_itree) { > + if (has_itree) { > ret = mn_itree_invalidate(subscriptions, range); > if (ret) > return ret; > } > if (!hlist_empty(&subscriptions->list)) > - return mn_hlist_invalidate_range_start(subscriptions, range); > - return 0; > + ret = mn_hlist_invalidate_range_start(subscriptions, range); > + > + /* > + * On error, the non-blocking caller is not allowed to call > + * invalidate_range_end(), as in mn_itree_invalidate(). > + */ > + if (ret && has_itree && !mmu_notifier_range_blockable(range)) > + mn_itree_inv_end(subscriptions); > + > + return ret; > } > > static void > > -- > 2.43.0 > -- Cheers, Lorenzo