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=-9.9 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,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 90344C10F29 for ; Tue, 17 Mar 2020 15:03:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3914D20735 for ; Tue, 17 Mar 2020 15:03:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="l254W5RQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726877AbgCQPDi (ORCPT ); Tue, 17 Mar 2020 11:03:38 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:34127 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726388AbgCQPDi (ORCPT ); Tue, 17 Mar 2020 11:03:38 -0400 Received: by mail-qk1-f194.google.com with SMTP id f3so32972425qkh.1 for ; Tue, 17 Mar 2020 08:03:37 -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=HqOBm7bQCludye1SGv0KdSFELKwpbPDMXnv2Sugq1V4=; b=l254W5RQNfFLpxh3XTCQBj64u0gip2PXizITExpY6lAOsWn1MUvIebu1an3ADb11ac liTXMm06RwsmMDI7Qxiw9AwtmT5Pq9dzz7YOo1yY/xONZZxMl1/9GUt/YT/Do+pTSGdB LbzJPXVYWH5ymK7O98yRz+R6EsdJ99oOZtKTikglOEznI557wq65BJDifgceaq5MjBtM MD2ztt6vDgt+RFxsqrUaKeQAXdaibVSfiqFDy2rYCj+/W/jcbmIRuSoa7Bwg0O0V5Q0Q gUkz99+eQIieLq631DL+LXAbdAOqEbiyoIYUQDsB+lgYPHYbAecWPCKStQ6zNYLvYJeX UiDQ== 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=HqOBm7bQCludye1SGv0KdSFELKwpbPDMXnv2Sugq1V4=; b=N/tG6mku+W/RR0MgGWvE2S5RIxXRHYSnAbUAperB/jOapNswYzhs0EPTl0EzCD59km 3ijCJimx+Hc8GKKwQUQdOxJeOSW7etBOB3oeLkgRbXrl6h7A4BiqaGfS8u3aorWc5/K5 w/AZUvNNr7meHHtrAjO0nEVMsDVV/DNswDzKlYHCetiuDYrZuuLJ5x92P88RyoOeUkCM IOt7wOtzDyxbz99xUQiDlMeuKshk9oDFWXHzd33xqXWXYKkVJ6a2L2tb6vaVnZ1ln6xv gkluAYP+DRqVBgZj+dh8z5rha5tQG7SAV0gPze+Fuo15rjQGTWL2151ToDWxyFd13F4q JoUw== X-Gm-Message-State: ANhLgQ1DwfonQSlGtfqjT6wvLEvw/SWs61xVATVIfIh1i4yU5cZjomYF tsGH/b+osUJSm5uOjCBbLbj/Ey9G5dddVw== X-Google-Smtp-Source: ADFU+vt5wqdAcnNu9Z6Fsgi+m9R2A9sC6GlSijeQ7cGL3zxioALaVGP0oa2V6N9J1JQpQHnNsM1vEQ== X-Received: by 2002:a37:5b82:: with SMTP id p124mr5447016qkb.130.1584457415620; Tue, 17 Mar 2020 08:03:35 -0700 (PDT) Received: from ovpn-66-200.rdu2.redhat.com (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id n74sm2037090qke.125.2020.03.17.08.03.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Mar 2020 08:03:34 -0700 (PDT) From: Qian Cai To: jroedel@suse.de Cc: baolu.lu@linux.intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH] iommu/vt-d: silence a RCU-list debugging warning Date: Tue, 17 Mar 2020 11:03:26 -0400 Message-Id: <20200317150326.1659-1-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 dmar_find_atsr() calls list_for_each_entry_rcu() outside of an RCU read side critical section but with dmar_global_lock held. Silence this false positive. drivers/iommu/intel-iommu.c:4504 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffff9755bee8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1a6/0xe19 Call Trace: dump_stack+0xa4/0xfe lockdep_rcu_suspicious+0xeb/0xf5 dmar_find_atsr+0x1ab/0x1c0 dmar_parse_one_atsr+0x64/0x220 dmar_walk_remapping_entries+0x130/0x380 dmar_table_init+0x166/0x243 intel_iommu_init+0x1ab/0xe19 pci_iommu_init+0x1a/0x44 do_one_initcall+0xae/0x4d0 kernel_init_freeable+0x412/0x4c5 kernel_init+0x19/0x193 Signed-off-by: Qian Cai --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 4be549478691..ef0a5246700e 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4501,7 +4501,8 @@ static struct dmar_atsr_unit *dmar_find_atsr(struct acpi_dmar_atsr *atsr) struct dmar_atsr_unit *atsru; struct acpi_dmar_atsr *tmp; - list_for_each_entry_rcu(atsru, &dmar_atsr_units, list) { + list_for_each_entry_rcu(atsru, &dmar_atsr_units, list, + dmar_rcu_check()) { tmp = (struct acpi_dmar_atsr *)atsru->hdr; if (atsr->segment != tmp->segment) continue; -- 2.21.0 (Apple Git-122.2)