From: Arjan van de Ven <arjan@linux.intel.com>
To: "Guilherme G. Piccoli" <gpiccoli@igalia.com>,
akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com,
kexec@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
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kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com,
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stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com,
vkuznets@redhat.com, will@kernel.org,
Cong Wang <xiyou.wangcong@gmail.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Valentin Schneider <valentin.schneider@arm.com>,
Xiaoming Ni <nixiaoming@huawei.com>
Subject: Re: [PATCH v2 09/13] notifier: Show function names on notifier routines if DEBUG_NOTIFIERS is set
Date: Tue, 19 Jul 2022 13:33:13 -0700 [thread overview]
Message-ID: <e292e128-d732-e770-67d7-b6ed947cec7b@linux.intel.com> (raw)
In-Reply-To: <20220719195325.402745-10-gpiccoli@igalia.com>
On 7/19/2022 12:53 PM, Guilherme G. Piccoli wrote:
> Currently we have a debug infrastructure in the notifiers file, but
> it's very simple/limited. Extend it by:
>
> (a) Showing all registered/unregistered notifiers' callback names;
I'm not yet convinced that this is the right direction.
The original intent for this "debug" feature was to be lightweight enough that it could run in production, since at the time, rootkits
liked to clobber/hijack notifiers and there were also some other signs of corruption at the time.
By making something print (even at pr_info) for what are probably frequent non-error operations, you turn something that is light
into something that's a lot more heavy and generally that's not a great idea... it'll be a performance surprise.
next prev parent reply other threads:[~2022-07-19 20:33 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 19:53 [PATCH v2 00/13] The panic notifiers refactor strikes back - fixes/clean-ups Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 01/13] ARM: Disable FIQs (but not IRQs) on CPUs shutdown paths Guilherme G. Piccoli
2022-08-07 15:35 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 02/13] notifier: Add panic notifiers info and purge trailing whitespaces Guilherme G. Piccoli
2022-08-03 9:21 ` Baoquan He
2022-07-19 19:53 ` [PATCH v2 03/13] firmware: google: Test spinlock on panic path to avoid lockups Guilherme G. Piccoli
2022-08-07 15:38 ` Guilherme G. Piccoli
2022-08-08 5:07 ` Evan Green
2022-08-08 15:14 ` Guilherme G. Piccoli
2022-08-08 15:26 ` Greg Kroah-Hartman
2022-08-08 15:37 ` Guilherme G. Piccoli
2022-08-10 12:54 ` Greg Kroah-Hartman
2022-07-19 19:53 ` [PATCH v2 04/13] soc: bcm: brcmstb: Document panic notifier action and remove useless header Guilherme G. Piccoli
2022-07-20 23:00 ` Florian Fainelli
2022-07-21 13:17 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 05/13] alpha: Clean-up the panic notifier code Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 06/13] um: Improve panic notifiers consistency and ordering Guilherme G. Piccoli
2022-08-07 15:40 ` Guilherme G. Piccoli
2022-08-09 18:09 ` Johannes Berg
2022-08-09 19:03 ` Guilherme G. Piccoli
2022-08-09 19:08 ` Johannes Berg
2022-08-09 19:45 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 07/13] parisc: Replace regular spinlock with spin_trylock on panic path Guilherme G. Piccoli
2022-07-20 1:43 ` Jeroen Roovers
2022-07-21 13:19 ` Guilherme G. Piccoli
2022-07-21 13:45 ` Helge Deller
2022-07-21 14:00 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 08/13] tracing: Improve panic/die notifiers Guilherme G. Piccoli
2022-08-03 9:36 ` Baoquan He
2022-08-03 9:52 ` Baoquan He
2022-08-03 11:44 ` Guilherme G. Piccoli
2022-08-07 15:46 ` Guilherme G. Piccoli
2022-08-16 14:14 ` Steven Rostedt
2022-08-16 14:57 ` Alan Stern
2022-08-16 15:52 ` Steven Rostedt
2022-08-16 20:12 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 09/13] notifier: Show function names on notifier routines if DEBUG_NOTIFIERS is set Guilherme G. Piccoli
2022-07-19 20:33 ` Arjan van de Ven [this message]
2022-07-19 20:44 ` Guilherme G. Piccoli
2022-07-19 20:48 ` Arjan van de Ven
2022-07-19 21:00 ` Guilherme G. Piccoli
2022-07-19 22:04 ` Arjan van de Ven
2022-07-21 13:20 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 10/13] EDAC/altera: Skip the panic notifier if kdump is loaded Guilherme G. Piccoli
2022-08-07 15:48 ` Guilherme G. Piccoli
2022-08-16 18:44 ` Dinh Nguyen
2022-08-16 20:16 ` Guilherme G. Piccoli
2022-08-17 17:31 ` Borislav Petkov
2022-08-17 18:45 ` Guilherme G. Piccoli
2022-08-17 19:34 ` Borislav Petkov
2022-08-17 20:28 ` Guilherme G. Piccoli
2022-08-17 21:02 ` Borislav Petkov
2022-08-17 21:39 ` Guilherme G. Piccoli
2022-08-17 21:46 ` Borislav Petkov
2022-08-17 21:56 ` Guilherme G. Piccoli
2022-08-17 22:00 ` Borislav Petkov
2022-08-17 22:09 ` Guilherme G. Piccoli
2022-08-17 22:19 ` Borislav Petkov
2022-08-17 22:49 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 11/13] video/hyperv_fb: Avoid taking busy spinlock on panic path Guilherme G. Piccoli
2022-07-25 18:09 ` Michael Kelley (LINUX)
2022-07-25 22:05 ` Guilherme G. Piccoli
2022-07-19 19:53 ` [PATCH v2 12/13] drivers/hv/vmbus, video/hyperv_fb: Untangle and refactor Hyper-V panic notifiers Guilherme G. Piccoli
2022-07-25 18:55 ` Michael Kelley (LINUX)
2022-07-19 19:53 ` [PATCH v2 13/13] panic: Fixes the panic_print NMI backtrace setting Guilherme G. Piccoli
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