From: Steven Rostedt <rostedt@goodmis.org>
To: Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Indu Bhagat <indu.bhagat@oracle.com>,
linux-toolchains@vger.kernel.org, daandemeyer@meta.com,
andrii@kernel.org, kris.van.hees@oracle.com,
elena.zannoni@oracle.com, nick.alcock@oracle.com
Subject: Re: [POC 5/5] x86_64: invoke SFrame based stack tracer for user space
Date: Wed, 13 Mar 2024 11:04:51 -0400 [thread overview]
Message-ID: <20240313110451.35458651@gandalf.local.home> (raw)
In-Reply-To: <C05CBE4B-DC97-4F4F-BFB8-A62A665C9F71@gmail.com>
On Wed, 13 Mar 2024 22:58:18 +0800
Tatsuyuki Ishi <ishitatsuyuki@gmail.com> wrote:
> > On Mar 13, 2024, at 22:52, Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > The simple answer is to call irq_work. That will trigger an interrupt when
> > irqs are enabled again (returning from NMI and just before entering user
> > space).
> >
> > The return from the irq_work can do the proper ptrace path.
> >
>
> Yeah, that makes sense. Thanks!
> Not sure how much overhead a self-IPI causes, compared to forging an IRET, but we can probably measure that later.
>
I brought up the "forging of an IRET" before, and was told about irq_work ;-)
The "forging of an IRET" from NMI will never make it upstream. The NMI
handling is already way too complex. Adding more complexity just for
tracing user space stack traces will never fly.
-- Steve
next prev parent reply other threads:[~2024-03-13 15:02 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-01 20:04 [POC 0/5] SFrame based stack tracer for user space in the kernel Indu Bhagat
2023-05-01 20:04 ` [POC 1/5] Kconfig: x86: Add new config options for userspace unwinder Indu Bhagat
2023-05-01 20:04 ` [POC 2/5] task_struct : add additional member for sframe state Indu Bhagat
2023-05-01 20:04 ` [POC 3/5] sframe: add new SFrame library Indu Bhagat
2023-05-01 22:40 ` Steven Rostedt
2023-05-02 5:07 ` Indu Bhagat
2023-05-02 8:46 ` Peter Zijlstra
2023-05-02 9:09 ` Peter Zijlstra
2023-05-02 9:20 ` Peter Zijlstra
2023-05-02 9:28 ` Peter Zijlstra
2023-05-02 9:30 ` Peter Zijlstra
2023-05-03 6:03 ` Indu Bhagat
2023-05-02 10:31 ` Peter Zijlstra
2023-05-02 10:41 ` Peter Zijlstra
2023-05-02 15:22 ` Steven Rostedt
2023-05-01 20:04 ` [POC 4/5] sframe: add an SFrame format stack tracer Indu Bhagat
2023-05-01 23:00 ` Steven Rostedt
2023-05-02 6:16 ` Indu Bhagat
2023-05-02 8:53 ` Peter Zijlstra
2023-05-02 9:04 ` Peter Zijlstra
2023-05-01 20:04 ` [POC 5/5] x86_64: invoke SFrame based stack tracer for user space Indu Bhagat
2023-05-01 23:11 ` Steven Rostedt
2023-05-02 10:53 ` Peter Zijlstra
2023-05-02 15:27 ` Steven Rostedt
2023-05-16 17:25 ` Andrii Nakryiko
2023-05-16 17:38 ` Steven Rostedt
2023-05-16 17:51 ` Andrii Nakryiko
2024-03-13 14:37 ` Tatsuyuki Ishi
2024-03-13 14:52 ` Steven Rostedt
2024-03-13 14:58 ` Tatsuyuki Ishi
2024-03-13 15:04 ` Steven Rostedt [this message]
2023-05-01 22:15 ` [POC 0/5] SFrame based stack tracer for user space in the kernel Steven Rostedt
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