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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLACK,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FBAAC433DF for ; Thu, 4 Jun 2020 15:04:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0692420829 for ; Thu, 4 Jun 2020 15:04:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="PHtn+4sW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729336AbgFDPEJ (ORCPT ); Thu, 4 Jun 2020 11:04:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729308AbgFDPEA (ORCPT ); Thu, 4 Jun 2020 11:04:00 -0400 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42DABC08C5C3 for ; Thu, 4 Jun 2020 08:03:59 -0700 (PDT) Received: by mail-qk1-x741.google.com with SMTP id b27so6301315qka.4 for ; Thu, 04 Jun 2020 08:03:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bm9LXKRTRAn4ksM+zTELl5Ncxt58Msz6smAUvbLwlQg=; b=PHtn+4sW9oeaaN0KqpSdfnAiSgGTHt2Z0UKpbIriHyOnPUd/JHuaYZWpEdpsIaFaRv YvPtCcDdD0ZUErBQIlaSncoBZYl91ggI8sYHqzw9bR/TZvqy6AN1xRyhmdNp28tW459k zc/ltDhaD7rxGMkMOSnh0JlRrzZf55P5fXoANCNcFe4PK35L1PIIi9SpADQrXNR7/ghu MRG8AChv3Sipl7YoDkSMO58dnI5vaMxvWgOk5kcvZCaGXGfX1ivy5tr2caHeF+hJbc9g 4QqkF2HCIZX77Q4uhgsSWHmxgVDjsPrrSuqruV5LzG4O1WK1yxB7R9xOKCdHrDOgU+UW UL+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bm9LXKRTRAn4ksM+zTELl5Ncxt58Msz6smAUvbLwlQg=; b=n5syVOTzdwXaRB7ZE/w32zM+DVp4TulIV1tOQvbtZt5Vy4AGa16orZHT8gPhf2WqVq jO8mWKloVzTEsqoBB/vxJOAGPf8YOO86zVFM8hT4piUfNh2LWpl2AfbjLoi+cSghdVSN hOvY4VlFOvKgKqgd5vH5gT9qFFZ83DPvsyPTDzGcf0nDFsfiRAF5e9EHBow0L4wWpQco 2e1MQQcwN+I5mJTT3RuXFONKM0o6Ep0YqvwxrzPdbI/BMVpaGVF5zf6UrP38yOGWXDlj c2z8zI7XcFjSnaJUxXLc3PQdV6GCzU419B3ZmT98tmJ5JIm/+rCOVMBanoTiKXItFICP PNhg== X-Gm-Message-State: AOAM532rl0beKh4m/eYVwSK7bj6ZtkWrEd7LC8k0Yf/drUBAZ18JvmcQ EopuIXr4XPH8la4vHTHkov9IEg== X-Google-Smtp-Source: ABdhPJxpiSlyIl8wDEUjWVCyb1O6lDkKyM6ZF/D0TVbA/KKrBsj4VNmpQA2CqhuZBuHgzP9j4gjV6g== X-Received: by 2002:a37:607:: with SMTP id 7mr4857940qkg.385.1591283038460; Thu, 04 Jun 2020 08:03:58 -0700 (PDT) Received: from ovpn-112-233.phx2.redhat.com (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id 205sm4560403qkh.94.2020.06.04.08.03.57 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Jun 2020 08:03:57 -0700 (PDT) From: Qian Cai To: peterz@infradead.org Cc: mark.rutland@arm.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH -next] fork: silence a false postive warning in __mmdrop Date: Thu, 4 Jun 2020 11:03:44 -0400 Message-Id: <20200604150344.1796-1-cai@lca.pw> X-Mailer: git-send-email 2.21.0 (Apple Git-122.2) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The linux-next commit bf2c59fce407 ("sched/core: Fix illegal RCU from offline CPUs") delayed, idle->active_mm = &init_mm; into finish_cpu() instead of idle_task_exit() which results in a false positive warning that was originally designed in the commit 3eda69c92d47 ("kernel/fork.c: detect early free of a live mm"). WARNING: CPU: 127 PID: 72976 at kernel/fork.c:697 __mmdrop+0x230/0x2c0 do_exit+0x424/0xfa0 Call Trace: do_exit+0x424/0xfa0 do_group_exit+0x64/0xd0 sys_exit_group+0x24/0x30 system_call_exception+0x108/0x1d0 system_call_common+0xf0/0x278 Fixes: bf2c59fce407 ("sched/core: Fix illegal RCU from offline CPUs") Signed-off-by: Qian Cai --- kernel/fork.c | 1 - 1 file changed, 1 deletion(-) diff --git a/kernel/fork.c b/kernel/fork.c index 142b23645d82..5334efd2a680 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -694,7 +694,6 @@ void __mmdrop(struct mm_struct *mm) { BUG_ON(mm == &init_mm); WARN_ON_ONCE(mm == current->mm); - WARN_ON_ONCE(mm == current->active_mm); mm_free_pgd(mm); destroy_context(mm); mmu_notifier_subscriptions_destroy(mm); -- 2.21.0 (Apple Git-122.2)