From: "Arnd Bergmann" <arnd@arndb.de>
To: "James Houghton" <jthoughton@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Alexander Viro" <viro@zeniv.linux.org.uk>
Cc: "Thomas Gleixner" <tglx@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Kees Cook" <kees@kernel.org>,
"David Hildenbrand (Red Hat)" <david@kernel.org>,
"Lorenzo Stoakes" <ljs@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
"Vlastimil Babka (SUSE)" <vbabka@kernel.org>,
"Mike Rapoport" <rppt@kernel.org>,
"Suren Baghdasaryan" <surenb@google.com>,
"Michal Hocko" <mhocko@suse.com>,
"Sean Christopherson" <seanjc@google.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Jim Mattson" <jmattson@google.com>,
"Jens Axboe" <axboe@kernel.dk>,
"Pavel Begunkov" <asml.silence@gmail.com>,
"James E . J . Bottomley" <James.Bottomley@hansenpartnership.com>,
"Martin K. Petersen" <mkp@kernel.org>,
"David Sterba" <dsterba@suse.com>,
"Chris Mason" <mason@kernel.org>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"John Fastabend" <john.fastabend@gmail.com>,
"Josh Poimboeuf" <jpoimboe@kernel.org>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Arnaldo Carvalho de Melo" <acme@kernel.org>,
"Namhyung Kim" <namhyung@kernel.org>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
kvm@vger.kernel.org, io-uring@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-btrfs@vger.kernel.org,
bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 00/10] uaccess: Refuse and warn on user accesses when current->mm is NULL
Date: Tue, 27 Oct 2026 11:33:08 +0100 [thread overview]
Message-ID: <3c125ff6-5426-4f19-8e34-fb564d4b6387@app.fastmail.com> (raw)
In-Reply-To: <14f5f919-55bd-47c6-a1c8-6f1445cce733@app.fastmail.com>
On Tue, Oct 27, 2026, at 01:12, Arnd Bergmann wrote:
>
> E.g. on arm64 with CONFIG_ARM64_SW_TTBR0_PAN, the page table base for
> the current process is only set in user_access_begin() and would
> not point to any task here. Without ttbr0_pan, it should be
> covered by cpu_set_reserved_ttbr0() turning off all user space access
> for kernel threads.
correction: for non-sw_ttbr0_pan, enter_lazy_tlb() does nothing
on arm64, so it is the same as x86 and the others.
Arnd
next prev parent reply other threads:[~2026-10-27 10:35 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-26 21:52 James Houghton
2026-10-26 21:52 ` [RFC PATCH 01/10] scsi: bsg: Don't copy sense data to user memory when canceled James Houghton
2026-10-27 2:41 ` Jens Axboe
2026-10-27 17:52 ` James Houghton
2026-10-26 21:52 ` [RFC PATCH 02/10] btrfs: Don't copy encoded read " James Houghton
2026-10-27 2:42 ` Jens Axboe
2026-10-26 21:52 ` [RFC PATCH 03/10] bpf: Fail sleepable user copy helpers when current->mm is NULL James Houghton
2026-10-26 22:30 ` bot+bpf-ci
2026-10-27 18:50 ` James Houghton
2026-10-26 21:52 ` [RFC PATCH 04/10] stacktrace: Don't unwind the user stack without an mm James Houghton
2026-10-26 22:30 ` bot+bpf-ci
2026-10-26 22:55 ` James Houghton
2026-10-26 21:52 ` [RFC PATCH 05/10] perf/core: " James Houghton
2026-10-27 11:09 ` Peter Zijlstra
2026-10-27 17:45 ` James Houghton
2026-10-26 21:52 ` [RFC PATCH 06/10] uaccess: Refuse and warn on user copies when current->mm is NULL James Houghton
2026-10-26 22:42 ` bot+bpf-ci
2026-10-26 23:41 ` James Houghton
2026-10-26 21:52 ` [RFC PATCH 07/10] uaccess: Fail user nofault helpers quietly " James Houghton
2026-10-26 21:52 ` [RFC PATCH 08/10] uaccess: Refuse and warn on __copy_from_user_inatomic() without an mm James Houghton
2026-10-26 22:30 ` bot+bpf-ci
2026-10-26 22:41 ` James Houghton
2026-10-26 21:52 ` [RFC PATCH 09/10] uaccess: Refuse and warn on more user accesses " James Houghton
2026-10-26 21:52 ` [RFC PATCH 10/10] uaccess: Move the NULL mm warning out of line James Houghton
2026-10-26 23:02 ` Arnd Bergmann
2026-10-26 23:51 ` James Houghton
2026-10-27 0:12 ` [RFC PATCH 00/10] uaccess: Refuse and warn on user accesses when current->mm is NULL Arnd Bergmann
2026-10-27 10:33 ` Arnd Bergmann [this message]
2026-10-27 17:29 ` James Houghton
2026-10-27 18:32 ` Arnd Bergmann
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