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 98622C433FE for ; Sat, 5 Mar 2022 14:49:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231901AbiCEOuH (ORCPT ); Sat, 5 Mar 2022 09:50:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231879AbiCEOuD (ORCPT ); Sat, 5 Mar 2022 09:50:03 -0500 Received: from out199-7.us.a.mail.aliyun.com (out199-7.us.a.mail.aliyun.com [47.90.199.7]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48935201BD for ; Sat, 5 Mar 2022 06:49:13 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R901e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=dtcccc@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0V6HF7it_1646491748; Received: from localhost.localdomain(mailfrom:dtcccc@linux.alibaba.com fp:SMTPD_---0V6HF7it_1646491748) by smtp.aliyun-inc.com(127.0.0.1); Sat, 05 Mar 2022 22:49:08 +0800 From: Tianchen Ding To: Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/2] kfence: Allow re-enabling KFENCE after system startup Date: Sat, 5 Mar 2022 22:48:57 +0800 Message-Id: <20220305144858.17040-2-dtcccc@linux.alibaba.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220305144858.17040-1-dtcccc@linux.alibaba.com> References: <20220305144858.17040-1-dtcccc@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Tianchen Ding --- mm/kfence/core.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 13128fa13062..caa4e84c8b79 100644 --- a/mm/kfence/core.c +++ b/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); /* Export for test modules. */ #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(const char *val, const struct kernel_param 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; -- 2.27.0