From: Steven Rostedt <rostedt@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
x86@kernel.org, Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@kernel.org>
Subject: Re: [PATCH v2 2/2] unwind deferred/x86: Do not defer stack tracing for compat tasks
Date: Tue, 23 Sep 2025 08:16:34 -0400 [thread overview]
Message-ID: <20250923081634.24ef8132@batman.local.home> (raw)
In-Reply-To: <20250923104515.GF3419281@noisy.programming.kicks-ass.net>
On Tue, 23 Sep 2025 12:45:15 +0200
Peter Zijlstra <peterz@infradead.org> wrote:
> Changelog seems to forget mentioning *why* we can't unwind compat.
>
> I'm sure I've seen compat FP unwind support at some point in this
> series. Did that go missing somewhere?
>
> Also, these two patches are in the wrong order, first you enable things,
> including compat tasks, and then you go 'whoopsie, no compats'.
Sure, we can swap it. Yes, we had patches to support it, but they
were a bit complicated and when I tested them, they didn't work. But
then I also noticed that the current stack tracing didn't work on
compat either. Instead of adding complicated code that wasn't working
on my machine, I decided to remove the patches. But after I did that, I
realized I needed to make sure it wasn't even tried, which is this
patch.
I'm not sure who needs profiling on compat code, and I figured we can
not add the new deferred work to it if it's not needed. If in the
future we need it, we can add it then.
-- Steve
prev parent reply other threads:[~2025-09-23 12:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-27 19:36 [PATCH v2 0/2] x86: Enable the deferred unwinding infrastructure Steven Rostedt
2025-08-27 19:36 ` [PATCH v2 1/2] unwind_user/x86: Enable frame pointer unwinding on x86 Steven Rostedt
2025-09-23 10:51 ` Peter Zijlstra
2025-09-23 12:20 ` Steven Rostedt
2025-08-27 19:36 ` [PATCH v2 2/2] unwind deferred/x86: Do not defer stack tracing for compat tasks Steven Rostedt
2025-09-23 10:45 ` Peter Zijlstra
2025-09-23 11:42 ` Peter Zijlstra
2025-09-23 12:16 ` Steven Rostedt [this message]
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