From: Christian Brauner <brauner@kernel.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: Alban Crequy <alban.crequy@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christian Brauner <brauner@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R . Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Alban Crequy <albancrequy@microsoft.com>,
Peter Xu <peterx@redhat.com>, Willy Tarreau <w@1wt.eu>,
linux-kselftest@vger.kernel.org, shuah@kernel.org,
Usama Arif <usama.arif@linux.dev>,
David Laight <david.laight.linux@gmail.com>
Subject: Re: [PATCH v5 1/2] mm/process_vm_access: pidfd and nowait support for process_vm_readv/writev
Date: Thu, 04 Jun 2026 14:49:44 +0200 [thread overview]
Message-ID: <20260604-ornament-sparen-biegung-e9930ee7444e@brauner> (raw)
In-Reply-To: <8e738cc8-dce8-4043-9b93-2bb867c43028@kernel.org>
On 2026-06-03 15:54 +0200, David Hildenbrand (Arm) wrote:
> > However, the exited-leader case is a real limitation for profilers.
> > OpenTelemetry eBPF Profiler wants to profile a process where the main thread
> > has exited but secondary threads are still running [2].
> > [2] https://github.com/open-telemetry/opentelemetry-ebpf-profiler/pull/376
> >
> > Using plain TIDs (flags=0) would work, but it means users cannot use
> > PROCESS_VM_PIDFD in this scenario.
> >
> > What do you think this patch should do? I see two options:
> > - Address this limitation in a separate future patch that fixes
> > pidfd_get_task() to use PIDTYPE_PID when PIDFD_THREAD is detected in
> > f_flags, benefiting all callers (process_vm_readv, process_madvise,
> > and any future users).
>
> Extending it consistently for that scenario seems like the right thing to do?
> @Christian?
Yes, but I cannot vouch whether the mm operations deal correctively with
subthreads.
next prev parent reply other threads:[~2026-06-04 12:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-02 10:09 [PATCH v5 0/2] " Alban Crequy
2026-06-02 10:09 ` [PATCH v5 1/2] " Alban Crequy
2026-06-02 12:16 ` David Hildenbrand (Arm)
2026-06-03 8:27 ` Alban Crequy
2026-06-03 13:54 ` David Hildenbrand (Arm)
2026-06-04 12:49 ` Christian Brauner [this message]
2026-06-05 9:31 ` David Hildenbrand (Arm)
2026-06-04 12:59 ` Christian Brauner
2026-06-02 10:09 ` [PATCH v5 2/2] selftests/mm: add tests for process_vm_readv flags Alban Crequy
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