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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) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 18BF71C0003 X-Stat-Signature: bmxjxhmo8fy1caikupqemozztj9eom8z X-HE-Tag: 1784317200-259238 X-HE-Meta: U2FsdGVkX19/JxK8Qp4PsDsJP2giYE3jMGq6Ral0s2VZVL6Va6bKxRRn5ekQ8g61p3DuqmcboHCrFgQLSYuXUbNgXk2A6TFBGUSFvkTUprvzXhu2uMphYzhvLNRZrbKuYXHOeB5hIXnkt7/l/BdTA/N2W2KTzafVKuGwXX25u2V+sPlKZdeuch9JjfmulJ/VnXrMH3SKrZAxHqwpJrf0m9h782Oin6shnKzHhzibqq6N9rD0PSvtGo39sdHleTNn8z7KLeXJMk7HMz5LjHM+OxrKawby9SEsLuH1cJdiese423gWLRLUeMtK1ozpvolPYD+xYWsWGFOjgjVAK9rQUkgUEg9JxmCzBryPhpdZJNjnw7YuZPF1x7fE3xXN1ACVyA+GSDjwPI7mU/tZJ8ZczBsSW8ESqgRGu6bQnYcLMcCw96NlukzJpaGHIhNqR8V6GQhZZ6v8lBYN2s09axwBhDB3nJyGke3K+T1nhqvnCRCZblyQWlkAkC1a9E5OEjbAEjZ+tC8q1xIwh/s6JlhPinRYImyHhwvJyZg/b1/Uw8vnQ4GTKEaiPGijwGg1GJYiFEcfAoTIp9RAevur66DZBt13dqOvwI4Cb0kDpcSSo/mwx1UWg1B1FcCYNab2fcxQs1ARobbe+i6l52MZkH/5jIBMAdemq57f48WWOqEFLoEKSFdpfgo9SjjLxJWZZ7BHQcsVoPPnbWWcg6f+Zm5qaOy9MqlDMWHL+QYQ0e5IhSY+sg2OG2KKYqxVRmlVTr6fLydeaKBjjaUvpv2xvQjxJEW+cE960DrUS25by0i21ovBOV5j1t6z22cAj6B2lwN1lZY/6wVT16ORgIB7FDJ+lvjejdqywVdtMe7lUxP45vaAj3wlcEakVHoGyqys9raCcDoGjKLrpVqtn8XGjWSTrlj1lY6FAFPprFeW3DV7DTeN8/hpHM403vMH/vYCrXYMjhsJXcTnAYNIYkIkW2H uNedgLiQ 0glUEX/NoS8Vbo60N6s8Ghhl6S2E57a8kowVqEqCG24OFnoGY9L+wtAUdJLXE9V6MC2a6jdG193WiYf3NYiqlEMyr9kLXf/RZJLmlVVyvsrJQ0MjSMjxGVT6KnbDojkWEcWJQNB6KRku7XzGBUGgVCNPr6Fk9k6iAQQwZJE4KQLrr2Y6cr91xktjYayBOXY/3/DfamjuuNusk0k9TugeGbpAE35tGdy2X8wfDpCRZHnAzwLJJyLo+cVNUc05RvqRFnJ3tpHju9ISFsyDA3Fw8jYNChYj22JG68esHWizPrd+XTsHqVVsTu1l3Mg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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); } _