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 53045606A31E for ; Sat, 31 Oct 2026 09:47:50 +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=bPmvjbd4; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=O0NtaK+z 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:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=MOMq9Bo/X1WC/1XHARd8rol7WFT4eC651ZyNYelwklc=; b=bPmvjbd4IyT2XV 6ChE2RUju2nodhksI9ymkSF7Yr2j+mObfSqc8SiBrSkXBnED9cicAoGyh5aNJYmItzp/Z2e7XTQRn 8I+HcI6hMupwofH0NLjhBs2hrP4ptL12YwPfxt/y2b5Dv4TfhH3/saBzrYnndxV/DzMADvoztsJKf H8+K7WafXxbtuGsKKNpUvIEWmFypLTrR7XICesu7ooGE0dLRwdEURr+gj6PwgAP7EmmnumqsqQWjQ 3iH1yj6MHZYfVOAHWeNZV9S6/mVi4euAfvGdyoU+rr6boQ1Ggcs1y2wfoe/eQLOJ47yDfAhT7hNX5 RcL19ELKkync+NBshlow==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xN5gk-0000000DAle-0D0W; Sat, 31 Oct 2026 09:47:50 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xN5gi-0000000DAl0-2N6w for kexec@lists.infradead.org; Sat, 31 Oct 2026 09:47:48 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 026D8605CF; Sat, 31 Oct 2026 09:47:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3A551F00A17; Sat, 31 Oct 2026 09:47:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793440067; bh=MOMq9Bo/X1WC/1XHARd8rol7WFT4eC651ZyNYelwklc=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=O0NtaK+zWEOTRhNj0gXjp5K/M/sd/Bb90jRBQ8hxQ8xq45quOyyco+pKYVCv/e+rC jhx/NuTe97ABxZM0ywKwuAkVP/8zauiAIanlyRXXeBf2qcu+GpTU8kayuT4pTPc6wP wRjJ+K+z15pP5Xqspp73jz1pH/YGC4A2MVaJImK2lf4YyVGpw4whdScowfQepp5Q0Y jgsWDMbZxDZIlwn7aVN8S7cUelh61nAK+j4mm7sfZGhXW8W5C5pVHlip46qyApgRNG CrNeTqwbPD0FxGz/bDqMXdcwxziaTEUSFttaYaxf6kT6j7DISoD3IkgQ64ctLSxHq/ 4Vue8gfskydlw== From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:39:58 +0100 Subject: [PATCH v3 29/47] mm/mmu_notifier: set ->mm only after mmgrab() X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261031-fixes_core-v3-29-d6437171ecc3@kernel.org> References: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> In-Reply-To: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> To: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , 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 Cc: 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, Chris Mason , stable@vger.kernel.org, Muhammad Usama Anjum , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2144; i=david@kernel.org; h=from:subject:message-id; bh=uqLLH/rw09nvp1DiWb73Ctop723Qk+Rw11zrHd74dEM=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebs+MUvecmTf/44Prj77M0zh96qmzHf/nTzWHYufcL FbkPxt5tqOUhUGMg0FWTJElKPi+wcuX62qr3fiYYeawMoEMYeDiFICJFDAw/DO/tLAiQThmaQNn jOOMa6u7DA9Y/vJat7y89k8vY2/2w6OMDPOV0/VfJLit+PLmfbHWH8PrXodfyJ0Kvdr66tLOiTJ Pn/ACAA== X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A 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=-18.9 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,USER_AGENT_GIT 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 From: Chris Mason Radeon uses a non-NULL notifier->mm to decide whether to call mmu_interval_notifier_remove() when freeing a buffer object. __mmu_interval_notifier_insert() sets ->mm before validating the range, so a wrapping userptr range can leave ->mm set after insertion fails. Cleanup then tries to remove an unregistered notifier for which no mm reference was acquired. Set ->mm only after mmgrab(), once insertion can no longer fail. While we could fix radeon's code instead, setting ->mm on success only makes the code more robust. Fix generated by an LLM and sent by Chris Mason in private. Fixes: 3506ff69c3ec ("drm/radeon: use mmu_interval_notifier_insert") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason [ david: simplify description ] Reviewed-by: Gregory Price (Meta) Tested-by: Gregory Price (Meta) Reviewed-by: Lorenzo Stoakes (ARM) Tested-by: Muhammad Usama Anjum Signed-off-by: David Hildenbrand (Arm) --- mm/mmu_notifier.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 2e20f88e162d7..a7bae5de5fedc 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -947,7 +947,6 @@ static int __mmu_interval_notifier_insert( struct mmu_notifier_subscriptions *subscriptions, unsigned long start, unsigned long length, const struct mmu_interval_notifier_ops *ops) { - interval_sub->mm = mm; interval_sub->ops = ops; RB_CLEAR_NODE(&interval_sub->interval_tree.rb); interval_sub->interval_tree.start = start; @@ -964,8 +963,12 @@ static int __mmu_interval_notifier_insert( if (WARN_ON(atomic_read(&mm->mm_users) <= 0)) return -EINVAL; - /* pairs with mmdrop in mmu_interval_notifier_remove() */ + /* + * Pairs with mmdrop in mmu_interval_notifier_remove(). Drivers take a + * non-NULL ->mm for "registered", so set it only with the reference. + */ mmgrab(mm); + interval_sub->mm = mm; /* * If some invalidate_range_start/end region is going on in parallel -- 2.43.0