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From: Steven Rostedt <rostedt@goodmis.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Jens Remus <jremus@linux.ibm.com>,
	Steven Rostedt <rostedt@kernel.org>,
	linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
	bpf@vger.kernel.org, x86@kernel.org,
	Masami Hiramatsu <mhiramat@kernel.org>,
	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>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jens Axboe <axboe@kernel.dk>, Florian Weimer <fweimer@redhat.com>,
	Sam James <sam@gentoo.org>, Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>
Subject: Re: [PATCH v8 06/12] unwind_user/sframe: Wire up unwind_user to sframe
Date: Wed, 9 Jul 2025 10:06:01 -0400	[thread overview]
Message-ID: <20250709100601.3989235d@batman.local.home> (raw)
In-Reply-To: <7250b957-2139-4c03-9566-a6ed9713584e@efficios.com>

On Wed, 9 Jul 2025 09:51:09 -0400
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:

> One use-case for giving the "current_type" to iteration callers is to
> let end users know whether they should trust the frame info. If it
> comes from sframe, then it should be pretty solid. However, if it comes
> from frame pointers used as a fallback on a system that omits frame
> pointers, the user should consider the resulting data with a high level
> of skepticism.

That would be in the trace sent to the callback. We could add something
like the '?' if it's not trusted.

But for now, until we have a use case that we are implementing, I want
to keep this simple, otherwise it will never get done. I don't want to
add features for hypothetical scenarios.

Currently, the traceback is just an array of addresses. But this could
change in the future. What we are discussing right now is the internal
functionality of the user unwind code where I have made most of theses
functions static.

The only external functions that get called during the iteration is the
architecture specific code. If that code needs to know the difference
between sframes and frame pointers then we can modify it, but until
then, I rather keep this as is.

Jens, is there something that the architecture code needs now? If so,
then lets fix it, otherwise lets do it when there is something. This
isn't user API, it can change in the future.

-- Steve

  reply	other threads:[~2025-07-09 14:06 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-08  2:11 [PATCH v8 00/12] unwind_deferred: Implement sframe handling Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 01/12] unwind_user/sframe: Add support for reading .sframe headers Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 02/12] unwind_user/sframe: Store sframe section data in per-mm maple tree Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 03/12] x86/uaccess: Add unsafe_copy_from_user() implementation Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 04/12] unwind_user/sframe: Add support for reading .sframe contents Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 05/12] unwind_user/sframe: Detect .sframe sections in executables Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 06/12] unwind_user/sframe: Wire up unwind_user to sframe Steven Rostedt
2025-07-08 19:58   ` Mathieu Desnoyers
2025-07-08 20:11     ` Steven Rostedt
2025-07-09  7:58       ` Jens Remus
2025-07-09 13:46         ` Mathieu Desnoyers
2025-07-09 13:51           ` Mathieu Desnoyers
2025-07-09 14:06             ` Steven Rostedt [this message]
2025-07-09 14:10               ` Mathieu Desnoyers
2025-07-09 14:29                 ` Steven Rostedt
2025-07-09 15:14                   ` Mathieu Desnoyers
2025-07-10  8:03               ` Jens Remus
2025-07-10  9:26             ` Jens Remus
2025-07-10 15:30         ` Steven Rostedt
2025-07-10 20:51           ` Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 07/12] unwind_user/sframe/x86: Enable sframe unwinding on x86 Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 08/12] unwind_user/sframe: Remove .sframe section on detected corruption Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 09/12] unwind_user/sframe: Show file name in debug output Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 10/12] unwind_user/sframe: Enable debugging in uaccess regions Steven Rostedt
2025-07-08  3:38   ` Linus Torvalds
2025-07-08 13:23     ` Steven Rostedt
2025-07-08 14:34       ` Josh Poimboeuf
2025-07-08 14:41         ` Steven Rostedt
2025-07-08 15:53           ` Linus Torvalds
2025-07-08 16:31             ` Steven Rostedt
2025-07-08 18:57               ` Josh Poimboeuf
2025-07-08 15:52         ` Linus Torvalds
2025-07-08  2:11 ` [PATCH v8 11/12] unwind_user/sframe: Add .sframe validation option Steven Rostedt
2025-07-08  2:11 ` [PATCH v8 12/12] unwind_user/sframe: Add prctl() interface for registering .sframe sections Steven Rostedt

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