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 AE6B237DE83; Fri, 17 Jul 2026 19:39:59 +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=1784317201; cv=none; b=qzDXZm/WC9EG3jYxSJJcAi0Vxs40uqCXqAQ0KYJuIqdDmKcJaW4f8pagreuv1z3eeVy/ex3aeVPdJIlVUOpJwy2ISGK+qFO1uasv5sQbHqOWEtDh5GvBw44Ankgi86n3Oa4uOZqc8I48JQpq3i1lXwwPW/UsAPNTAKZ0dzh1qD4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784317201; c=relaxed/simple; bh=2BHBvmEceLpdIMGV6pi05ueLebiOBwEM3DoGVguQTxM=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=tZhdDGiwqGrovZMNnEzYWC/8ueQwuZybOb8aXpD/0B58pf1R8p5uFpdeQxrjWTxMBKJlIB39x2ckCL72NRaOeHFYAlr2jvnGKhecpoPKSlxuIa4cMryFTBab0Ck6UQaaX7KH3FC3uqoucT8H5p6ndfWjl3Pzxc1xi7KpYg+rYFc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=MwZTrKk3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="MwZTrKk3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D3D91F000E9; Fri, 17 Jul 2026 19:39:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1784317199; bh=iyfkphrqCeDRYVOH+L7t1qg0gMyCglA6AMvMBV+tJlA=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=MwZTrKk3vTa1tRaaX4wi2tiU/4Vrt4o7NMcor3OxIkZ5EFBHemIIi7ZLnr5ZdnRGf gEFBn9kxOmX12rdjTPzpBi72IDFLyHRCjeG1MGX1YPD25GABaRCY4IAbi16flGaiLW P+mH4TNOiikbaY+skDjOEDSsHu3LFUhXVm8KpI44= Date: Fri, 17 Jul 2026 12:39:58 -0700 From: Andrew Morton To: "Lorenzo Stoakes (ARM)" Cc: "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , Alexander Viro , Christian Brauner , Jan Kara , Kees Cook , David Hildenbrand , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 0/3] mm/mseal: further cleanups Message-Id: <20260717123958.98f965ed7996804e6157b399@linux-foundation.org> In-Reply-To: <20260717-mseal-fixups-v2-0-0daa0014b813@kernel.org> References: <20260717-mseal-fixups-v2-0-0daa0014b813@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 17 Jul 2026 18:27:08 +0100 "Lorenzo Stoakes (ARM)" wrote: > > The mseal implementation is still rather confusing, so tighten things up a > little. > > The only user of do_mseal() outside of the system call is the MMAP_PAGE_ZERO > process personality - retain better control over how mseal is utilised by > providing mseal_mmap_page_zero() for this instead. > > The comments are overly long and confusion, so cut them down so they're a lot > clearer. > > Remove confusing mm_struct params (mseal can not be used on remote mm's) and > wrap the actual system call logic into the system call declaration. Thanks, I've updated mm-new to this version. > v2: > * Added tags (thanks everyone!) > * Abstracted mm as per David. > * Renamed [__]mseal() to [__]mseal_range() as per Pedro. > * Moved to reverse xmas tree declarations. > * Tweaked commit message for 2/3. Here's how v2 altered mm.git: mm/mseal.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) --- a/mm/mseal.c~b +++ a/mm/mseal.c @@ -18,9 +18,9 @@ static bool range_contains_unmapped(unsigned long start, unsigned long end) { - struct vm_area_struct *vma; - unsigned long prev_end = start; VMA_ITERATOR(vmi, current->mm, start); + unsigned long prev_end = start; + struct vm_area_struct *vma; for_each_vma_range(vmi, vma, end) { if (vma->vm_start > prev_end) @@ -32,10 +32,10 @@ static bool range_contains_unmapped(unsi return prev_end < end; } -static int __mseal(unsigned long start, unsigned long end) +static int __mseal_range(unsigned long start, unsigned long end) { - struct vm_area_struct *vma, *prev; VMA_ITERATOR(vmi, current->mm, start); + struct vm_area_struct *vma, *prev; /* We know there are no gaps so this will be non-NULL. */ vma = vma_iter_load(&vmi); @@ -66,7 +66,7 @@ static int __mseal(unsigned long start, return 0; } -static int mseal(unsigned long start, unsigned long end) +static int mseal_range(unsigned long start, unsigned long end) { int err; @@ -76,7 +76,7 @@ static int mseal(unsigned long start, un if (range_contains_unmapped(start, end)) err = -ENOMEM; else - err = __mseal(start, end); + err = __mseal_range(start, end); mmap_write_unlock(current->mm); return err; } @@ -92,7 +92,7 @@ void mseal_mmap_page_zero(void) if (WARN_ON_ONCE(!(current->personality & MMAP_PAGE_ZERO))) return; - err = mseal(0, PAGE_SIZE); + err = mseal_range(0, PAGE_SIZE); if (err) pr_warn_ratelimited("pid=%d, couldn't seal address 0, ret=%d.\n", task_pid_nr(current), err); @@ -139,5 +139,5 @@ SYSCALL_DEFINE3(mseal, unsigned long, st if (end == start) return 0; - return mseal(start, end); + return mseal_range(start, end); } _