From nobody Thu May 7 16:16:41 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4BDA7C433EF for ; Tue, 24 May 2022 21:23:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241910AbiEXVXN (ORCPT ); Tue, 24 May 2022 17:23:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235078AbiEXVXL (ORCPT ); Tue, 24 May 2022 17:23:11 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57AEA71A24 for ; Tue, 24 May 2022 14:23:10 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: dmitry.osipenko) with ESMTPSA id 36DE91F44798 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1653427388; bh=+4kY50wvvK8xnfpL7EAb+VQqUenC2VyyO6SNi5GVpOE=; h=From:To:Cc:Subject:Date:From; b=RyqEPqC7N8HkeMwEeJ5oYO9oIji6w9zMNumE8OwDsEls/1s1SLhXRonUSz2oCItTb M0uKojoWMkkwjsxx3RfpQdpHCAaqQpuE/aS1UvYGnEpZrnVNjMtVOmAcQFB51ql7qm SpEs/Qo0h2pceUDpyCqUQMednqVsNGcIpwzp46J/VZQQo5Xaozn365hlqK+t2r1189 TmPEZi8xhie3GjGY/Ke1JHN8IjsA79V3JfEqu1xmlEBnlG9roC9WFsHTGqBqPI8y4j E0gzC5mBB8Zgo3d/aQlBhSuByw9QQNt2M/ZU5gQESXtt7jLPK5ph0G5cci2p7XLzyM kK/cBYHqMRGsg== From: Dmitry Osipenko To: "Rafael J . Wysocki" , Geert Uytterhoeven Cc: linux-kernel@vger.kernel.org Subject: [PATCH v1] kernel/reboot: Change registration order of legacy power-off handler Date: Wed, 25 May 2022 00:21:18 +0300 Message-Id: <20220524212118.425702-1-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" We're unconditionally registering sys-off handler for the legacy pm_power_off() callback, this causes problem for platforms that don't use power-off handlers at all and should be halted. Now reboot syscall assumes that there is a power-off handler installed and tries to power off system instead of halting it. To fix the trouble, move the handler's registration to the reboot syscall and check the pm_power_off() presence. Fixes: 0e2110d2e910 ("kernel/reboot: Add kernel_can_power_off()") Reported-by: Geert Uytterhoeven Tested-by: Geert Uytterhoeven Signed-off-by: Dmitry Osipenko Tested-by: Michael Ellerman --- kernel/reboot.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/kernel/reboot.c b/kernel/reboot.c index 0bdc64ecf4f6..a091145ee710 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -569,22 +569,6 @@ static int legacy_pm_power_off(struct sys_off_data *da= ta) return NOTIFY_DONE; } =20 -/* - * Register sys-off handlers for legacy PM callbacks. This allows legacy - * PM callbacks co-exist with the new sys-off API. - * - * TODO: Remove legacy handlers once all legacy PM users will be switched - * to the sys-off based APIs. - */ -static int __init legacy_pm_init(void) -{ - register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT, - legacy_pm_power_off, NULL); - - return 0; -} -core_initcall(legacy_pm_init); - static void do_kernel_power_off_prepare(void) { blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL); @@ -646,6 +630,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsig= ned int, cmd, void __user *, arg) { struct pid_namespace *pid_ns =3D task_active_pid_ns(current); + struct sys_off_handler *sys_off =3D NULL; char buffer[256]; int ret =3D 0; =20 @@ -670,6 +655,21 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsi= gned int, cmd, if (ret) return ret; =20 + /* + * Register sys-off handlers for legacy PM callback. This allows + * legacy PM callbacks temporary co-exist with the new sys-off API. + * + * TODO: Remove legacy handlers once all legacy PM users will be + * switched to the sys-off based APIs. + */ + if (pm_power_off) { + sys_off =3D register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, + SYS_OFF_PRIO_DEFAULT, + legacy_pm_power_off, NULL); + if (IS_ERR(sys_off)) + return PTR_ERR(sys_off); + } + /* Instead of trying to make the power_off code look like * halt when pm_power_off is not set do it the easy way. */ @@ -727,6 +727,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsig= ned int, cmd, break; } mutex_unlock(&system_transition_mutex); + unregister_sys_off_handler(sys_off); return ret; } =20 --=20 2.35.3