From: Kees Cook <kees@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
bpf@vger.kernel.org, x86@kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrii Nakryiko <andrii@kernel.org>,
Indu Bhagat <indu.bhagat@oracle.com>,
"Jose E. Marchesi" <jemarch@gnu.org>,
Beau Belgrave <beaub@linux.microsoft.com>,
Jens Remus <jremus@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>, Florian Weimer <fweimer@redhat.com>
Subject: Re: [PATCH v12 00/14] unwind_user: x86: Deferred unwinding infrastructure
Date: Wed, 2 Jul 2025 07:56:06 -0700 [thread overview]
Message-ID: <202507020751.CB3EFC2D@keescook> (raw)
In-Reply-To: <20250701192619.20eb2a58@gandalf.local.home>
On Tue, Jul 01, 2025 at 07:26:19PM -0400, Steven Rostedt wrote:
> On Tue, 1 Jul 2025 15:49:23 -0700 Kees Cook <kees@kernel.org> wrote:
> > Okay, I've read the cover letter and this wiki page, but I am dense: why
> > does the _kernel_ want to do this? Shouldn't it only be userspace that
> > cares about userspace unwinding? I don't use perf, ftrace, and ebpf
> > enough to make this obvious to me, I guess. ;)
> [...]
> Anyway, yeah, it's something that has a ton of interest, as it's the way
> for tools like perf to give nice graphs of where user space bottlenecks
> exist.
Right! Yeah, I know it's very wanted -- I wasn't saying "don't this in
the kernel", but quite literally, "*I* am missing something about why
this is so important." :) And thank you, now I see: the sampling-based
profiling of userspace must happen via the kernel.
--
Kees Cook
next prev parent reply other threads:[~2025-07-02 14:56 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-01 0:53 [PATCH v12 00/14] unwind_user: x86: Deferred unwinding infrastructure Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 01/14] unwind_user: Add user space unwinding API Steven Rostedt
2025-07-04 17:58 ` Mathieu Desnoyers
2025-07-04 18:20 ` Mathieu Desnoyers
2025-07-07 19:42 ` Steven Rostedt
2025-07-07 21:01 ` Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 02/14] unwind_user: Add frame pointer support Steven Rostedt
2025-07-01 2:10 ` Linus Torvalds
2025-07-01 2:56 ` Steven Rostedt
2025-07-01 3:05 ` Steven Rostedt
2025-07-01 15:36 ` Jens Remus
2025-07-02 23:50 ` Steven Rostedt
2025-07-03 16:21 ` Jens Remus
2025-07-07 21:28 ` Steven Rostedt
2025-07-01 4:46 ` Florian Weimer
2025-07-01 12:14 ` Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 03/14] unwind_user: Add compat mode " Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 04/14] unwind_user/deferred: Add unwind_user_faultable() Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 05/14] unwind_user/deferred: Add unwind cache Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 06/14] unwind_user/deferred: Add deferred unwinding interface Steven Rostedt
2025-07-02 16:36 ` Peter Zijlstra
2025-07-02 16:42 ` Steven Rostedt
2025-07-02 16:56 ` Linus Torvalds
2025-07-02 17:26 ` Steven Rostedt
2025-07-02 17:48 ` Steven Rostedt
2025-07-02 18:21 ` Linus Torvalds
2025-07-02 18:47 ` Mathieu Desnoyers
2025-07-02 19:05 ` Steven Rostedt
2025-07-02 19:12 ` Mathieu Desnoyers
2025-07-02 19:21 ` Steven Rostedt
2025-07-02 19:36 ` Steven Rostedt
2025-07-02 19:40 ` Steven Rostedt
2025-07-02 19:48 ` Mathieu Desnoyers
2025-07-02 20:10 ` Steven Rostedt
2025-07-02 19:43 ` Mathieu Desnoyers
2025-07-02 19:51 ` Steven Rostedt
2025-07-02 18:57 ` Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 07/14] unwind_user/deferred: Make unwind deferral requests NMI-safe Steven Rostedt
2025-07-02 15:53 ` Jens Remus
2025-07-02 19:11 ` Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 08/14] unwind deferred: Use bitmask to determine which callbacks to call Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 09/14] unwind deferred: Use SRCU unwind_deferred_task_work() Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 10/14] unwind: Clear unwind_mask on exit back to user space Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 11/14] unwind: Add USED bit to only have one conditional on way " Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 12/14] unwind: Finish up unwind when a task exits Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 13/14] unwind_user/x86: Enable frame pointer unwinding on x86 Steven Rostedt
2025-07-01 0:53 ` [PATCH v12 14/14] unwind_user/x86: Enable compat mode " Steven Rostedt
2025-07-01 2:06 ` [PATCH v12 00/14] unwind_user: x86: Deferred unwinding infrastructure Linus Torvalds
2025-07-01 2:45 ` Steven Rostedt
2025-07-01 22:49 ` Kees Cook
2025-07-01 23:26 ` Steven Rostedt
2025-07-02 14:56 ` Kees Cook [this message]
2025-07-02 16:20 ` Mathieu Desnoyers
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