From mboxrd@z Thu Jan 1 00:00:00 1970 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 67F5CC433EF for ; Sun, 6 Mar 2022 23:44:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234478AbiCFXpO (ORCPT ); Sun, 6 Mar 2022 18:45:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233054AbiCFXpN (ORCPT ); Sun, 6 Mar 2022 18:45:13 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 890D23FBFE for ; Sun, 6 Mar 2022 15:44:20 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 22008610A1 for ; Sun, 6 Mar 2022 23:44:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F6F2C340EC; Sun, 6 Mar 2022 23:44:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1646610259; bh=ASdWsBAY97aPJ5m7eaaDmNsbcEi5F/WP2uMBBUW4TGk=; h=Date:To:From:Subject:From; b=dKEdS6TTxwK3LsdxRalxL8ZAtjFHTk3zKlI393yCkgDKUFiaD079roE/TIe74PRxe lFUw8iDJHrfdPd3HtCWO1XqsJC4uHtTBLIpg/HUEheLDLOlNfpRALe9jzWZKeS+OQf FEcQJK4mkffG/mvSiQ+FI+vu785PXgUWkzrrLNLc= Date: Sun, 06 Mar 2022 15:44:18 -0800 To: mm-commits@vger.kernel.org, glider@google.com, elver@google.com, dvyukov@google.com, dtcccc@linux.alibaba.com, akpm@linux-foundation.org From: Andrew Morton Subject: + kfence-allow-re-enabling-kfence-after-system-startup.patch added to -mm tree Message-Id: <20220306234419.6F6F2C340EC@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: kfence: allow re-enabling KFENCE after system startup has been added to the -mm tree. Its filename is kfence-allow-re-enabling-kfence-after-system-startup.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/kfence-allow-re-enabling-kfence-after-system-startup.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/kfence-allow-re-enabling-kfence-after-system-startup.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Tianchen Ding Subject: kfence: allow re-enabling KFENCE after system startup Patch series "provide the flexibility to enable KFENCE", v2. This patch (of 2): If once KFENCE is disabled by: echo 0 > /sys/module/kfence/parameters/sample_interval KFENCE could never be re-enabled until next rebooting. Allow re-enabling it by writing a positive num to sample_interval. Link: https://lkml.kernel.org/r/20220305144858.17040-1-dtcccc@linux.alibaba.com Link: https://lkml.kernel.org/r/20220305144858.17040-2-dtcccc@linux.alibaba.com Signed-off-by: Tianchen Ding Cc: Alexander Potapenko Cc: Marco Elver Cc: Dmitry Vyukov Signed-off-by: Andrew Morton --- mm/kfence/core.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) --- a/mm/kfence/core.c~kfence-allow-re-enabling-kfence-after-system-startup +++ a/mm/kfence/core.c @@ -38,14 +38,17 @@ #define KFENCE_WARN_ON(cond) \ ({ \ const bool __cond = WARN_ON(cond); \ - if (unlikely(__cond)) \ + if (unlikely(__cond)) { \ WRITE_ONCE(kfence_enabled, false); \ + disabled_by_warn = true; \ + } \ __cond; \ }) /* === Data ================================================================= */ static bool kfence_enabled __read_mostly; +static bool disabled_by_warn __read_mostly; unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL; EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */ @@ -55,6 +58,7 @@ EXPORT_SYMBOL_GPL(kfence_sample_interval #endif #define MODULE_PARAM_PREFIX "kfence." +static int kfence_enable_late(void); static int param_set_sample_interval(const char *val, const struct kernel_param *kp) { unsigned long num; @@ -65,10 +69,11 @@ static int param_set_sample_interval(con if (!num) /* Using 0 to indicate KFENCE is disabled. */ WRITE_ONCE(kfence_enabled, false); - else if (!READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) - return -EINVAL; /* Cannot (re-)enable KFENCE on-the-fly. */ *((unsigned long *)kp->arg) = num; + + if (num && !READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) + return disabled_by_warn ? -EINVAL : kfence_enable_late(); return 0; } @@ -787,6 +792,16 @@ void __init kfence_init(void) (void *)(__kfence_pool + KFENCE_POOL_SIZE)); } +static int kfence_enable_late(void) +{ + if (!__kfence_pool) + return -EINVAL; + + WRITE_ONCE(kfence_enabled, true); + queue_delayed_work(system_unbound_wq, &kfence_timer, 0); + return 0; +} + void kfence_shutdown_cache(struct kmem_cache *s) { unsigned long flags; _ Patches currently in -mm which might be from dtcccc@linux.alibaba.com are kfence-allow-re-enabling-kfence-after-system-startup.patch kfence-alloc-kfence_pool-after-system-startup.patch