From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E03A84EDCB6; Thu, 17 Sep 2026 16:38:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789663097; cv=none; b=rJSW0ETW/s6Qa6pBfxKhiLesTabTLSgvpkLSiwQ7N3L3//am4x5z6If73u9anE1f5zJfGuiuzp4o5XjtZRYmVoA0b5xrMlBBWYIcRAskk29L62wU0nn8rnaC9OBgpa7Ix/USQ41xggieEgFlPAPfpjP4FLcazGDPDjCReNPE3C4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789663097; c=relaxed/simple; bh=sRYt0UudvtAxeO0KRMBxTGrVTVnQqrjgMi1gjOlaTgw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=KEkCDPwmv2AC8wW4nBTRb2JSmXr9xVE4YbmFjrPJLg+OaitECcJSoNy+Yww+LzgjEGJY9bg9PezJ1UgJ0BcbM5+o7b7TaP0x9KLYYCnakJcYIQCY1vmk+aqfaQbMukTLn3C3nbkXVGlJTscnpikG2sR7GhfywzOqI5RzyJNhNz0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ll2Iicn3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ll2Iicn3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B02B21F00893; Thu, 17 Sep 2026 16:37:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789663095; bh=rpQUY90Yz1fvoWb/n9qt0DfA+MP9PvsomcDJoStRF6M=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Ll2Iicn3dYLgP4VwRxvy63UrleSMOQQihXo/WomzR/sIEgx5GaKP4U+NW4Lb0bdNp uKjkDJge8PuQIeTx9lnMRLm03IMp1Usw/GKzwcJQy9xCKnuyLOibVtPP+3NaWmIfZT ZxaOtwCuRFmWdwDLcRNeXUWweQKJVep+O0QYRR3W5MGGqwDUTXSmmaGOrV9k3gu/Fa u4yjykT0wypyKnk5NYG7PJcfN5++PgNEyYQC0MtsFxZyVsHLk1xvjf6T0bH/rgeu5t NRxxmzLWXr+qmM0VFyQYndVUgdCXL+qJqjapaQtC3XKXDw2eAGFrjqHohQPTZrDgH3 R+ck8e2+gcVKQ== From: "Lorenzo Stoakes (ARM)" Date: Thu, 17 Sep 2026 17:22:39 +0100 Subject: [PATCH v3 30/40] mm/madvise: update is_valid_guard_vma() to use vma_can_merge() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-30-4583d8a23bca@kernel.org> References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> In-Reply-To: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> To: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , David Hildenbrand , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Greg Kroah-Hartman , Dennis Dalessandro , Jason Gunthorpe , Leon Romanovsky , Paul Moore , Stephen Smalley , Jaroslav Kysela , Takashi Iwai , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Doug Gilbert , "James E.J. Bottomley" , "Martin K. Petersen" , Jaya Kumar , Simona Vetter , Helge Deller , Sebastian Reichel , John Hubbard , Peter Xu , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Rik van Riel , Harry Yoo , Juri Lelli , Vincent Guittot , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Arnd Bergmann , Muchun Song , Oscar Salvador , "Matthew Wilcox (Oracle)" , Jan Kara , Marc Zyngier , Oliver Upton , Catalin Marinas , Madhavan Srinivasan , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , "David S. Miller" , Andreas Larsson , Alexander Viro , Christian Brauner , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , Johannes Weiner , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-rdma@vger.kernel.org, selinux@vger.kernel.org, linux-sound@vger.kernel.org, bpf@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, fuse-devel@lists.linux.dev, "Lorenzo Stoakes (ARM)" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1939; i=ljs@kernel.org; h=from:subject:message-id; bh=sRYt0UudvtAxeO0KRMBxTGrVTVnQqrjgMi1gjOlaTgw=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLLWCB9WPht5l03vgd2TQ69yb55Xv/rEwXSmdfm3m/rap meO2wrLd5SyMIhxMciKKbI8/yK+P0gkbF7nBX83mDmsTCBDGLg4BWAiZzMZ/oq8MfRPzp0m6HHF 2O+Uz78FWXzx1+YWB72v57T8UWDxaAIjwwxWiS8XZ3ObaDKydWiYvLkWGv19mpb787Ol671e/RL M4wMA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 We currently disallow the installation of lightweight guard regions in VMAs whose flags intersect VMA_SPECIAL_FLAGS or VMA_HUGETLB_BIT, or VMA_LOCKED_BIT unless allow_locked is set. hugetlb VMAs set VMA_DONTEXPAND_BIT so this was already redundant, VMA_SPECIAL_FLAGS already sufficed. However, now that VMA_IO_BIT is only set if VMA_PFNMAP or VMA_MIXEDMAP_BIT is set, this check collapses to being the equivalent of !vma_can_merge(). Update is_valid_guard_vma() to reflect this. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/madvise.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 467601a8525b..0922d5f07a12 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1221,19 +1221,25 @@ static long madvise_remove(struct madvise_behavior *madv_behavior) return error; } -static bool is_valid_guard_vma(struct vm_area_struct *vma, bool allow_locked) +static bool is_valid_guard_vma(const struct vm_area_struct *vma, + bool allow_locked) { - vm_flags_t disallowed = VM_SPECIAL | VM_HUGETLB; - /* - * A user could lock after setting a guard range but that's fine, as + * A user could lock after setting a guard range but that's fine as * they'd not be able to fault in. The issue arises when we try to zap * existing locked VMAs. We don't want to do that. */ - if (!allow_locked) - disallowed |= VM_LOCKED; + if (!allow_locked && vma_test(vma, VMA_LOCKED_BIT)) + return false; + /* + * Guard regions require a VMA whose page tables are managed solely by + * the core, which is also what merging requires, so disallow any flags + * that would prevent a merge. + */ + if (!vma_can_merge(vma)) + return false; - return !(vma->vm_flags & disallowed); + return true; } static bool is_guard_pte_marker(pte_t ptent) -- 2.55.0