From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1D085677 for ; Sat, 13 Jan 2024 18:17:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=purestorage.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b="Ybj6Y9PN" Received: by mail-pj1-f41.google.com with SMTP id 98e67ed59e1d1-28c7e30c83fso4863692a91.1 for ; Sat, 13 Jan 2024 10:17:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=purestorage.com; s=google2022; t=1705169839; x=1705774639; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=iYp2logoMYZ9jMW04gIUzqQcpGYG2bO16WsCcwCZkXw=; b=Ybj6Y9PNa6A2klF87TLk2lvOw63CntnlgKbxhblWTY9w2cu5YJV9hQ05cYsTZp2FTH maLcz8hYIo9e4u+XfAC4GpTPu+4YSdVSXfsCTEphQ4HRt4RyvvTpMfTf1UXCRw5gKUpj yG+xdZ6Fhn1qqpgU7a7l4zOIB3sgHwc85X0Ja5kcyB4APlJ1vYK+nDRrVViV8cBfndWA WgebC8esFI6gq8ds8b1sdv/9HnAI7Vmd4BToMCl8ON1mFXnzggEi+KOtke2Rs3riCyYs cShEvaqWWJJeLtuPnsmOtw1UNTpx5EfOsA5fxtqssJvGng9TI8aOEvxy259BQ8ADWY61 5iXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705169839; x=1705774639; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=iYp2logoMYZ9jMW04gIUzqQcpGYG2bO16WsCcwCZkXw=; b=flQ3OmFIpOXdnqM50BgUMBJmuRpcIFUZofDOVr75WCs5v7JM9hfAM/77cPL2+tY2IR JFTc4sid9AX50hJOhleOiH9HnNZaWKQGMcWNWTAdQt0iOd5Y9U2tZO9s1f6CBEnzxW/Z rcPfngjHYD0v0LAMd2U8j1HzSzW5F43mqoAZSXWdwWdUovIIX8KXXzt33KMbL8uC/Ocx m+WYDc97aC96btOYYi4sS0ZKNtXIHGW3u41c6VkFUgPcWedJiz3uuvg5G957dd+MtDUp SnNItcmqtFmVspPl+F4an4t5fb6NeSiM033aTwpKHvi2rReNWLOIhs2vyz8n/Q2zkBE5 G9uQ== X-Gm-Message-State: AOJu0Yy2dQLE1KSTYRagHIf6/xHP4aAAPKoYSdkeFCvFv3lbs/vGdZ9x tbogizgisQCrb9107hzolm+WGdAjWKoX0Q== X-Google-Smtp-Source: AGHT+IFHhiY0Ruu2VzN4smgoixnnM3AliTiNgFa93KGVhnKCHSbLCXgydKs8mFTkyx0O5aHwb8BbtA== X-Received: by 2002:a17:902:f68c:b0:1d4:20b8:abfb with SMTP id l12-20020a170902f68c00b001d420b8abfbmr2051519plg.68.1705169839215; Sat, 13 Jan 2024 10:17:19 -0800 (PST) Received: from localhost ([192.30.189.3]) by smtp.gmail.com with UTF8SMTPSA id v20-20020a170902d09400b001d563e22dc0sm5059233plv.1.2024.01.13.10.17.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 13 Jan 2024 10:17:18 -0800 (PST) From: Eric Badger To: ebadger@purestorage.com Cc: David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Robin Murphy , iommu@lists.linux.dev (open list:INTEL IOMMU (VT-d)), linux-kernel@vger.kernel.org (open list) Subject: [PATCH] iommu/vt-d: Check for non-NULL domain on device release Date: Sat, 13 Jan 2024 10:17:13 -0800 Message-Id: <20240113181713.1817855-1-ebadger@purestorage.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In the kdump kernel, the IOMMU will operate in deferred_attach mode. In this mode, info->domain may not yet be assigned by the time the release_device function is called, which leads to the following crash in the crashkernel: BUG: kernel NULL pointer dereference, address: 000000000000003c ... RIP: 0010:do_raw_spin_lock+0xa/0xa0 ... _raw_spin_lock_irqsave+0x1b/0x30 intel_iommu_release_device+0x96/0x170 iommu_deinit_device+0x39/0xf0 __iommu_group_remove_device+0xa0/0xd0 iommu_bus_notifier+0x55/0xb0 notifier_call_chain+0x5a/0xd0 blocking_notifier_call_chain+0x41/0x60 bus_notify+0x34/0x50 device_del+0x269/0x3d0 pci_remove_bus_device+0x77/0x100 p2sb_bar+0xae/0x1d0 ... i801_probe+0x423/0x740 Signed-off-by: Eric Badger --- drivers/iommu/intel/iommu.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 6fb5f6fceea1..26e450259889 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -3750,7 +3750,6 @@ static void domain_context_clear(struct device_domain_info *info) static void dmar_remove_one_dev_info(struct device *dev) { struct device_domain_info *info = dev_iommu_priv_get(dev); - struct dmar_domain *domain = info->domain; struct intel_iommu *iommu = info->iommu; unsigned long flags; @@ -3763,11 +3762,14 @@ static void dmar_remove_one_dev_info(struct device *dev) domain_context_clear(info); } - spin_lock_irqsave(&domain->lock, flags); + if (!info->domain) + return; + + spin_lock_irqsave(&info->domain->lock, flags); list_del(&info->link); - spin_unlock_irqrestore(&domain->lock, flags); + spin_unlock_irqrestore(&info->domain->lock, flags); - domain_detach_iommu(domain, iommu); + domain_detach_iommu(info->domain, iommu); info->domain = NULL; } -- 2.34.1