From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
bpf@vger.kernel.org, Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <liam@infradead.org>,
linux-kselftest@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
John Fastabend <john.fastabend@gmail.com>
Subject: Re: [RFC bpf-next 0/9] bpf: Add support to allocate user page
Date: Thu, 22 Oct 2026 11:27:28 +0100 [thread overview]
Message-ID: <atnk5kjaeHLhbxVh@gremlin> (raw)
In-Reply-To: <DMAUMG9WL4X6.12UEJJMJSW54Z@gmail.com>
On Wed, Oct 21, 2026 at 09:53:47PM +0000, Alexei Starovoitov wrote:
> On Wed, Oct 21, 2026 at 12:57 PM Jiri Olsa <jolsa@kernel.org> wrote:
> > hi,
> > we have few use cases where having the ability to allocate normal
> > or executable user space memory would help (like to replace function
> > in live process or change environment variables)
>
> I think it's better to do what debuggers do:
> vm_mmap() with the final prot and
> access_process_vm(FOLL_FORCE | FOLL_WRITE), like PTRACE_POKETEXT,
> to fill it. It faults the pages in, writes into r-x private mapping
> and copy_to_user_page() takes care of icache.
> Then no need for bpf_user_page_exec(), do_mprotect_pkey_locked(),
> the marker, READ_IMPLIES_EXEC special case, get_user_pages(), etc.
> No mm changes.
OK thanks that addresses my concerns :)
--
Cheers, Lorenzo
prev parent reply other threads:[~2026-10-22 10:27 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-21 19:57 [RFC bpf-next 0/9] bpf: Add support to allocate user page Jiri Olsa
2026-10-21 19:57 ` [RFC bpf-next 1/9] bpf: Add __srcptr kfunc argument suffix Jiri Olsa
2026-10-21 19:57 ` [RFC bpf-next 2/9] bpf: Add uprobe faultable user copy kfunc Jiri Olsa
2026-10-21 20:30 ` bot+bpf-ci
2026-10-21 19:57 ` [RFC bpf-next 3/9] mm: Expose locked mprotect operation Jiri Olsa
2026-10-21 20:30 ` bot+bpf-ci
2026-10-22 10:25 ` Lorenzo Stoakes (ARM)
2026-10-22 19:39 ` Jiri Olsa
2026-10-21 19:57 ` [RFC bpf-next 4/9] bpf: Add kfuncs to allocate and seal user pages Jiri Olsa
2026-10-21 20:41 ` bot+bpf-ci
2026-10-21 19:57 ` [RFC bpf-next 5/9] selftests/bpf: Add __srcptr kfunc arguments test Jiri Olsa
2026-10-21 19:57 ` [RFC bpf-next 6/9] selftests/bpf: Add user page allocation test Jiri Olsa
2026-10-21 19:57 ` [RFC bpf-next 7/9] selftests/bpf: Add uprobe user page exec test Jiri Olsa
2026-10-21 19:57 ` [RFC bpf-next 8/9] selftests/bpf: Add faultable user page writes test Jiri Olsa
2026-10-21 19:57 ` [RFC bpf-next 9/9] selftests/bpf: Add user page failures test Jiri Olsa
2026-10-21 20:30 ` bot+bpf-ci
2026-10-21 21:53 ` [RFC bpf-next 0/9] bpf: Add support to allocate user page Alexei Starovoitov
2026-10-22 10:01 ` Jiri Olsa
2026-10-22 10:27 ` Lorenzo Stoakes (ARM) [this message]
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