From: Dexuan Cui <decui@microsoft.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jeyu@kernel.org" <jeyu@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"ardb@kernel.org" <ardb@kernel.org>
Subject: RE: static_branch_enable() does not work from a __init function?
Date: Wed, 16 Dec 2020 20:45:26 +0000 [thread overview]
Message-ID: <MW4PR21MB18570800B5A2E4C6B578D69EBFC59@MW4PR21MB1857.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20201216105926.GS3092@hirez.programming.kicks-ass.net>
> From: Peter Zijlstra <peterz@infradead.org>
> Sent: Wednesday, December 16, 2020 2:59 AM
> ...
> So I think the reason your above module doesn't work, while the one in
> vmx_init() does work (for 5.10) should be fixed by the completely
> untested below.
>
> I've no clue about 5.4 and no desire to investigate. That's what distro
> people are for.
>
> Can you verify?
>
> ---
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index 015ef903ce8c..c6a39d662935 100644
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -793,6 +793,7 @@ int jump_label_text_reserved(void *start, void *end)
> static void jump_label_update(struct static_key *key)
> {
> struct jump_entry *stop = __stop___jump_table;
> + bool init = system_state < SYSTEM_RUNNING;
> struct jump_entry *entry;
> #ifdef CONFIG_MODULES
> struct module *mod;
> @@ -804,15 +805,16 @@ static void jump_label_update(struct static_key
> *key)
>
> preempt_disable();
> mod = __module_address((unsigned long)key);
> - if (mod)
> + if (mod) {
> stop = mod->jump_entries + mod->num_jump_entries;
> + init = mod->state == MODULE_STATE_COMING;
> + }
> preempt_enable();
> #endif
> entry = static_key_entries(key);
> /* if there are no users, entry can be NULL */
> if (entry)
> - __jump_label_update(key, entry, stop,
> - system_state < SYSTEM_RUNNING);
> + __jump_label_update(key, entry, stop, init);
> }
>
> #ifdef CONFIG_STATIC_KEYS_SELFTEST
Yes, this patch fixes the issue found by the test module for both
v5.10 and v5.4.
Thank you, Peter!
Dexuan
next prev parent reply other threads:[~2020-12-16 20:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-16 3:54 static_branch_enable() does not work from a __init function? Dexuan Cui
2020-12-16 9:26 ` Peter Zijlstra
2020-12-16 10:59 ` Peter Zijlstra
2020-12-16 13:30 ` [RFC][PATCH] jump_label/static_call: Add MAINTAINERS Peter Zijlstra
2020-12-16 13:42 ` Peter Zijlstra
2020-12-16 14:23 ` Steven Rostedt
2020-12-16 16:19 ` Josh Poimboeuf
2020-12-16 16:19 ` Ard Biesheuvel
2020-12-16 21:16 ` Jason Baron
2020-12-16 13:54 ` [PATCH] jump_label: Fix usage in module __init Peter Zijlstra
2020-12-16 16:36 ` Josh Poimboeuf
2020-12-16 20:45 ` Dexuan Cui [this message]
2020-12-16 11:55 ` static_branch_enable() does not work from a __init function? Jessica Yu
2020-12-16 12:47 ` Peter Zijlstra
2020-12-16 13:10 ` Jessica Yu
2020-12-16 13:23 ` Peter Zijlstra
2020-12-16 13:27 ` Jessica Yu
2020-12-16 12:38 ` Jessica Yu
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