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From: Steven Rostedt <>
To: Joel Fernandes <>
	Jessica Yu <>,,,
Subject: Re: [PATCH v3 3/3] module: Make __tracepoints_ptrs as read-only
Date: Thu, 11 Apr 2019 09:19:55 -0400	[thread overview]
Message-ID: <20190411091955.67cdd9fd@gandalf.local.home> (raw)
In-Reply-To: <>

On Thu, 11 Apr 2019 04:21:06 -0400
Joel Fernandes <> wrote:

> Patch 2/3 and 3/3 would not be nececessary if this works out. 1/3 may be a
> nice clean up but is not something urgent and we could do that in the future
> if needed.

Well, jump_labels is "special" because it requires sorting the RO data
and is done via module notify. The only other user that had to modify
RO data on module load is ftrace. It had to do the nop conversions in
the text area. It use to do it via module notify, but because of the
hardening of the kernel, doing it there was no longer possible because
everything was RO then. The solution was to call into ftrace directly
from the module code instead of a notifier. This was done before
sections were made RO.

One option is to do the same with jump_labels and just have a call to
the sorting before the notifiers and before the section gets turned
into RO. Or I would say just leave it as is. As I stated, jump_labels
are "special" and adding a loop of one section where I don't envision
any other sections needing to do the same thing for a long time to
come. I would save that patch for if there is another section that
comes along that needs to be modify at module notify.

-- Steve

  reply	other threads:[~2019-04-11 13:19 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-10 19:57 [PATCH v3 1/3] module: Prepare for addition of new ro_after_init sections Joel Fernandes (Google)
2019-04-10 19:57 ` [PATCH v3 2/3] module: Make srcu_struct ptr array as read-only post init Joel Fernandes (Google)
2019-04-10 19:57 ` [PATCH v3 3/3] module: Make __tracepoints_ptrs as read-only Joel Fernandes (Google)
2019-04-10 20:11   ` Steven Rostedt
2019-04-10 20:29     ` Joel Fernandes
2019-04-11  0:44       ` Steven Rostedt
2019-04-11  8:21         ` Joel Fernandes
2019-04-11 13:19           ` Steven Rostedt [this message]
2019-04-11 20:06             ` Joel Fernandes
2019-04-11 13:44           ` Paul E. McKenney
2019-04-17 15:16         ` Jessica Yu
2019-04-17 15:36           ` Paul E. McKenney
2019-04-20 11:38           ` Joel Fernandes
2019-04-11  8:32 ` [PATCH v3 1/3] module: Prepare for addition of new ro_after_init sections Miroslav Benes
2019-04-17 13:29 ` Jessica Yu

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