From: Jessica Yu <jeyu@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
x86@kernel.org, jbaron@akamai.com, ardb@kernel.org,
linux-kernel@vger.kernel.org, sumit.garg@linaro.org,
oliver.sang@intel.com, jarkko@kernel.org
Subject: Re: [PATCH 3/3] static_call: Fix static_call_update() sanity check
Date: Mon, 22 Mar 2021 18:36:24 +0100 [thread overview]
Message-ID: <YFjVmFgXdsIIkGRV@gunter> (raw)
In-Reply-To: <YFjLqKV9GxGSXcAr@hirez.programming.kicks-ass.net>
+++ Peter Zijlstra [22/03/21 17:54 +0100]:
>On Mon, Mar 22, 2021 at 03:50:14PM +0100, Jessica Yu wrote:
>
>> It should be doable. If you want the exit sections to be treated the same as
>> module init, the following patch should stuff any exit sections into the module
>> init "region" (completely untested). Hence it should be freed together with the
>> init sections and it would identify as init through within_module_init(). Let
>> me know if this works for you.
>
>That does indeed seem to DTRT from a quick scan of module.c. Very nice
>tidy patch. I was afraid it'd be much worse.
>
>Assuming it actually works; for your Changelog:
>
>"Dynamic code patching (alternatives, jump_label and static_call) can
>have sites in __exit code, even it __exit is never executed. Therefore
>__exit must be present at runtime, at least for as long as __init code
>is.
>
>Additionally, for jump_label and static_call, the __exit sites must also
>identify as within_module_init(), such that the infrastructure is aware
>to never touch them after module init -- alternatives are only ran once
>at init and hence don't have this particular constraint.
>
>By making __exit identify as __init for UNLOAD_MODULE, the above is
>satisfied."
Thanks a lot for the changelog :-) I'll turn this into a formal patch
after some testing tomorrow.
Jessica
next prev parent reply other threads:[~2021-03-22 17:37 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 11:31 [PATCH 0/3] static_call() vs __exit fixes Peter Zijlstra
2021-03-18 11:31 ` [PATCH 1/3] static_call: Fix static_call_set_init() Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-18 11:31 ` [PATCH 2/3] static_call: Align static_call_is_init() patching condition Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-19 13:31 ` [PATCH 2/3] " Rasmus Villemoes
2021-03-19 14:13 ` Peter Zijlstra
2021-03-19 14:40 ` Rasmus Villemoes
2021-03-19 15:44 ` Rasmus Villemoes
2021-03-22 16:59 ` Peter Zijlstra
2021-03-18 11:31 ` [PATCH 3/3] static_call: Fix static_call_update() sanity check Peter Zijlstra
2021-03-18 11:42 ` Peter Zijlstra
2021-03-18 16:13 ` Josh Poimboeuf
2021-03-18 16:58 ` Peter Zijlstra
2021-03-19 12:57 ` Peter Zijlstra
2021-03-19 18:00 ` Steven Rostedt
2021-03-19 19:34 ` Peter Zijlstra
2021-03-19 20:57 ` Steven Rostedt
2021-03-22 14:50 ` Jessica Yu
2021-03-22 16:54 ` Peter Zijlstra
2021-03-22 17:36 ` Jessica Yu [this message]
2021-03-22 13:07 ` Jessica Yu
2021-03-22 14:06 ` Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-18 12:15 ` [PATCH 0/3] static_call() vs __exit fixes Sumit Garg
2021-03-18 19:38 ` Jarkko Sakkinen
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