From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Dexuan Cui <decui@microsoft.com>, 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, ardb@kernel.org
Subject: Re: [PATCH] jump_label: Fix usage in module __init
Date: Wed, 16 Dec 2020 10:36:13 -0600 [thread overview]
Message-ID: <20201216163613.nyrd25vakui2tdiy@treble> (raw)
In-Reply-To: <20201216135435.GV3092@hirez.programming.kicks-ass.net>
On Wed, Dec 16, 2020 at 02:54:35PM +0100, Peter Zijlstra wrote:
> Subject: jump_label: Fix usage in module __init
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Wed Dec 16 12:21:36 CET 2020
>
> When the static_key is part of the module, and the module calls
> static_key_inc/enable() from it's __init section *AND* has a
> static_branch_*() user in that very same __init section, things go
> wobbly.
>
> If the static_key lives outside the module, jump_label_add_module()
> would append this module's sites to the key and jump_label_update()
> would take the static_key_linked() branch and all would be fine.
>
> If all the sites are outside of __init, then everything will be fine
> too.
>
> However, when all is aligned just as described above,
> jump_label_update() calls __jump_label_update(.init = false) and we'll
> not update sites in __init text.
>
> Fixes: 19483677684b ("jump_label: Annotate entries that operate on __init code earlier")
> Reported-by: Dexuan Cui <decui@microsoft.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
next prev parent reply other threads:[~2020-12-16 16:38 UTC|newest]
Thread overview: 20+ 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
2020-12-18 16:02 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2020-12-16 13:54 ` [PATCH] jump_label: Fix usage in module __init Peter Zijlstra
2020-12-16 16:36 ` Josh Poimboeuf [this message]
2020-12-18 16:02 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2020-12-16 20:45 ` static_branch_enable() does not work from a __init function? Dexuan Cui
2020-12-16 11:55 ` 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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