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 B1AF85275B1; Thu, 17 Sep 2026 16:34:42 +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=1789662884; cv=none; b=o6u09RJQYtSAsvNXLpY8Azocca4DvZ5mMJFHVdzrxVj7oDmUU3NkmM31SanbQY6rVS50pbqHnFNsY5hMuhgBIwrYODSckR80myJxaAfMunQwALi7Onk8QmRuOgsI7X1y2uOGi6Td6fZ8rp8DWcGZjYILGwQlj7JI+bT3bvup+yk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789662884; c=relaxed/simple; bh=LP2OVTJBUZHnaHZyV54sJNvm4xxGiJDQinrnPbsdCWM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gVUHPGPFOi1Jyhd6+abHlabAlewf8pFx/kOsChIzc3JRKnbd/A3g1icDNHvFE/eJLzZmY0DUM+vc9LDbvORNjyHKoiLk0E2yWjANy0/ZNYgw1ca0DRuAevzB7XYWVjp/gTtpvTbtutkkDm9OoDxJmlIZkQZIuXUlRcPrM2UvShI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HrTjhgWc; 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="HrTjhgWc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B430A1F00898; Thu, 17 Sep 2026 16:34:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789662882; bh=vZ2BcQjAwuwkC6/1VounDnE32rIC0Hjr2OUSnxyIkA8=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=HrTjhgWc4//TyGo0MLAC3WMKB3trg0Da9llQBlNoG2CpnsE0E+nakCyji8mxZQpme VxHtk/idNgtQHfSor0Csyd9oGbaEoBYWo5jU9iNQ8ixYYL7YholnWwWdjJ4ajhiULo Rt8HXHFM9s9qJkcNIEd9WiyFvrIxm8Ob2Yziy+8eirXWq3iHf+8bU1EthZuZAvWGTz XibJ9IjZMVpXZBSOt2SVbDtXwXstrt0FCqmIib4HPGqMeXtQTPrE7Dj694QH14hQGs VddhDCAHjtM8xo5QTvEBLv6Je7pdirLDgUavvQkghweAOYclDKp41x5BVF7eVbvUlz 2c2X7fiXPR9PQ== From: "Lorenzo Stoakes (ARM)" Date: Thu, 17 Sep 2026 17:22:32 +0100 Subject: [PATCH v3 23/40] mm/mlock: clear VMA_LOCKED_MASK over mmap callback Precedence: bulk X-Mailing-List: linux-fbdev@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-v3-23-4583d8a23bca@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=2686; i=ljs@kernel.org; h=from:subject:message-id; bh=LP2OVTJBUZHnaHZyV54sJNvm4xxGiJDQinrnPbsdCWM=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLLWCB86ImDlv7d0LV9pyYYSnTXehbNvS6Z4eWg9PxvNf 6c17ItuRykLgxgXg6yYIsvzL+L7g0TC5nVe8HeDmcPKBDKEgYtTACZSpcPwT/Gqj2rCgy9S2gsd lH2dxR687NLN9Zwt0l65W7fT43ykNCNDR/dUtWOr0gLXbTrNuv1CZ2Dqc3WLVGmxJ92z5f9UPAr kBQA= X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Currently there's a confusing mess around VMA_LOCKED_BIT and VMA_LOCKONFAULT_BIT. It is permitted for drivers to set any flags they like, with the VMA already possessing lock flags. This results in the absurd situation of a VMA possessing both VMA_SPECIAL_FLAGS and VMA_LOCKED_MASK flags, which is not permitted. This has resulted in mlock_vma_folio() having a very silly check for this scenario to work around it. There is no need for this - just clear the flags before invoking the hook and reinstate them afterwards if they are required. Nothing relies upon this being set during the mmap operation. mmap_prepare is unaffected by this so requires no fix. Signed-off-by: Lorenzo Stoakes (ARM) --- mm/internal.h | 9 +-------- mm/vma.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 8 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index b81fce5fe510..b2c6c9435021 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -971,14 +971,7 @@ void mlock_folio(struct folio *folio); static inline void mlock_vma_folio(struct folio *folio, struct vm_area_struct *vma) { - /* - * The VM_SPECIAL check here serves two purposes. - * 1) VM_IO check prevents migration from double-counting during mlock. - * 2) Although mmap_region() and mlock_fixup() take care that VM_LOCKED - * is never left set on a VM_SPECIAL vma, there is an interval while - * file->f_op->mmap() is using vm_insert_page(s), when VM_LOCKED may - * still be set while VM_SPECIAL bits are added: so ignore it then. - */ + /* The VM_IO check prevents migration from double-counting during mlock. */ if (unlikely((vma->vm_flags & (VM_LOCKED|VM_SPECIAL)) == VM_LOCKED)) mlock_folio(folio); } diff --git a/mm/vma.c b/mm/vma.c index 1dec10946918..1db8b218fe64 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2607,6 +2607,11 @@ static int __mmap_new_file_vma(struct mmap_state *map, if (!map->vm_file->f_op->mmap) return 0; + /* + * Driver-specified flags may make the lock flags invalid, so clear + * VMA_LOCKED_MASK and reinstate it afterwards if appropriate. + */ + vma_clear_flags_mask(vma, VMA_LOCKED_MASK); error = mmap_file(vma->vm_file, vma); map->vm_file = vma->vm_file; @@ -2623,6 +2628,15 @@ static int __mmap_new_file_vma(struct mmap_state *map, return error; } + /* If VMA flags still valid for locked mask, reinstate. */ + if (vma_supports_mlock(vma)) { + const vma_flags_t mask = + vma_flags_and_mask(&map->vma_flags, + VMA_LOCKED_MASK); + + vma_set_flags_mask(vma, mask); + } + map->vma_flags = vma->flags; return 0; -- 2.55.0