From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793440021; b=ph2b8KUT8CC+8aI+Ih0rsxoluZjL3hvgYZmHp+befecyl6piXGomqUVTcqTO1Q2QGmMJ OEqGUHAsry08CzjX0qDQXU7Lp6XEtt+Zh7Z11bU4t4x667+5lu8dDlaExSg+1Ar2LPczd h/qQqXp/sPYLSly53P0x5Gkg8NA5nzpojajabBiu+3VNqUa8oCMSgsaPeqJM/HVNahqR4 2b6N1eh6zqMbwFIJYFcj+Kxa/vtWv2o3RQpMehcGabBNlP2Tkikdu6qqSK7csSvliM8LL BqLYBsLE+ecrAzqG1dAmfpwnTLTsel/iuJ3uBW0fR908Dm6rfkK8gw8R8Q+s3SYqsKA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793440021; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=gNn7/nSxmNJguW2bsADoqLsPI7cv25lI/JHeobxIgIk=; b=wukvSeIeNrXCjsurhGB2f3pe/ELohPOlIfFPCOirkeIriuRZ0FYsBmaA5j4R3hRbTafT GH5eQOSmIWzgWPrnOm4Ybq0gIonmzTXw94yfymylTwgkthKbmDsJ0aQyVpVBU2wszVG7I A8DUrzeJx135OigzYCP69xRW0Njr+3PQr8V/h6UWKdwMvSFJ//w6mSv5QqLGPMCwUdrfX GQq5Xc3XsrBj+5tKJ1I0MrbTiAdDS6AoGHv5HwHGkmEsuKUsfRYAykdf+IwXyIbMCzrqL wV+e3B4UfHfZiEw4W/9KFW4biQ1FKvaMO/hUwDfjUi2O/WBsPwH91/iUV7hdPXQ7LdQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Goo08VUO; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0DF0606A322; Sat, 31 Oct 2026 09:47:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Goo08VUO Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3A131F0093A; Sat, 31 Oct 2026 09:46:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793440020; bh=gNn7/nSxmNJguW2bsADoqLsPI7cv25lI/JHeobxIgIk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Goo08VUOyTuxB+9BiU8tT1hGY7xIbPlcSmnFKYKLEns6CjMozp+42PLDwlris0Wgy Epy0qZs9ruATYG7k3H09RtPnyDeTrQWjydx2A76PkzWc/HJEqku1kfq+YGHjvzgiu7 PVzQSIFw2G73kn0/TmY4S7YikUWi5ZjSlNlCvW8sTI4Xwv03qxL3EhI9T4GGCOuzOS wqesxAZme6fwCbZotjvP7RH+qDfB95lIIOdkup1BldzJkCVJXYxqy9DC9vPqebcprH uLdmoGd5Ixnvi0Tvgq2KahgXTyv1qFs3LN+TYfkQH8ipONbe0mXOCdtPulAg5ZVhx7 dsOwRYfOdSfgQ== From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:39:55 +0100 Subject: [PATCH v3 26/47] mm/userfaultfd: compare exact registration modes before skipping X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261031-fixes_core-v3-26-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, 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=1520; i=david@kernel.org; h=from:subject:message-id; bh=VPLF7ZF60P6QZsc5ogJFtB1G0DgMIn6ux/cdpuH/iTQ=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebs/ojGKyT+C9PCWZu/jAdn/xR/eWdutsjRLU8tn3S GhxtmtcRykLgxgHg6yYIktQ8H2Dly/X1Va78THDzGFlAhnCwMUpABNZIMzwV1CyVabwyaF8oQum Z0+LdgcvbTw/7Wih/MHrHFWK3NvDDzD8Ffi01Oet/XuBJXyLvH7pvd019+vmjPjl/i3pgnKt0x3 OsgMA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A From: Gregory Price Changing registration from MISSING|WP to WP returns success but leaves MISSING enabled. The no-op check sees that WP is already set and skips the update, so later accesses to missing pages still wait for userspace. Skip the update only when the current and requested UFFD modes match exactly. Fixes: 63b2d4174c4a ("userfaultfd: wp: add the writeprotect API to userfaultfd ioctl") Cc: stable@vger.kernel.org Signed-off-by: Gregory Price (Meta) [ david: apply fixup from Lorenzo ] Tested-by: Muhammad Usama Anjum Signed-off-by: David Hildenbrand (Arm) --- mm/userfaultfd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 03f1b15bfe63e..dac696bda19f0 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -2291,6 +2291,7 @@ static int userfaultfd_register_range(struct userfaultfd_ctx *ctx, for_each_vma_range(vmi, vma, end) { const bool any_mode_removed = vma->vm_flags & __VM_UFFD_FLAGS & ~vm_flags; + const vma_flags_t curr_vma_flags = vma_flags_and_mask(&vma->flags, __VMA_UFFD_FLAGS); cond_resched(); @@ -2304,7 +2305,7 @@ static int userfaultfd_register_range(struct userfaultfd_ctx *ctx, * userfaultfd and with the right tracking mode too. */ if (vma->vm_userfaultfd_ctx.ctx == ctx && - vma_test_all_mask(vma, vma_flags)) + vma_flags_same_pair(&curr_vma_flags, &vma_flags)) goto skip; /* -- 2.43.0