From: Jason Baron <jbaron@akamai.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: jim.cromie@gmail.com, gregkh@linuxfoundation.org,
linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v2 2/2] dyndbg: use the module notifier callbacks
Date: Tue, 28 Feb 2023 16:56:59 -0500 [thread overview]
Message-ID: <c0c38c08-a329-9d0a-ca75-0519b589731e@akamai.com> (raw)
In-Reply-To: <Y/5ntkYoKHvfU9S8@bombadil.infradead.org>
On 2/28/23 3:44 PM, Luis Chamberlain wrote:
> On Tue, Feb 28, 2023 at 02:35:02PM -0500, Jason Baron wrote:
>> As part of Jim Cromie's new dynamic debug classmap feature, the new code
>> tries to toggle a jump label from dynamic_debug_setup(). However,
>> dynamic_debug_setup() is called before the 'module_notify_list' notifier
>> chain is invoked. And jump labels are initialized via the module notifier
>> chain. Note this is an issue for a new feature not yet merged and doesn't
>> affect any existing codepaths.
>
> I think we can summarize this to "in preperation for some future work where
> ordering matters with respect to jump labels" or something like that.
>
> Because that is then making it specific to the future use case and
> creates the current justification.
>
>> We could just move dynamic_debug_setup() earlier in load_module(). But
>> let's instead ensure the ordering via the 'priority' in the module list
>> notifier.
>
> "becuase the notifier for jump labels jump_label_module_nb uses a
> priority of 1" or something like that would be nice to get added.
>
>> This brings dynamic debug more in line with other subsystems and
>> pulls code out of the core module code.
>
> This should be the main reason for this change, as explained in the
> commit log. A secondary benefit would be it fixes the first future bug
> mentioned.
>
> With those changes I can take this into modules-next to start getting
> this tested sooner rather than later.
>
> Luis
Hi Luis,
Ok, I can fix up the commit message and re-post. I'm thinking maybe we
should separate these patches as they are independent. The 2nd one I
think makes sense to go through modules-next, but the first one is
internal to dynamic debug and can be a part of Jim's series. Make sense?
Thanks,
-Jason
next prev parent reply other threads:[~2023-02-28 21:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-28 19:34 [PATCH v2 0/2] dyndbg: let's use the module notifier callback Jason Baron
2023-02-28 19:34 ` [PATCH v2 1/2] dyndbg: remove unused 'base' arg from __ddebug_add_module() Jason Baron
2023-02-28 20:38 ` Luis Chamberlain
2023-03-01 2:12 ` jim.cromie
2023-03-09 18:31 ` Vincenzo Palazzo
2023-03-09 20:58 ` Luis Chamberlain
2023-02-28 19:35 ` [PATCH v2 2/2] dyndbg: use the module notifier callbacks Jason Baron
2023-02-28 20:44 ` Luis Chamberlain
2023-02-28 21:56 ` Jason Baron [this message]
2023-02-28 23:34 ` Luis Chamberlain
2023-02-28 20:18 ` [PATCH v2 0/2] dyndbg: let's use the module notifier callback Luis Chamberlain
2023-02-28 20:28 ` Jason Baron
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