From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C530217F26; Thu, 12 Dec 2024 15:35:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734017717; cv=none; b=F35wZHf1jF1J9fdo2w5CXjJjQHGOnlO+/0OjF6qp9jxDsZxOcUZ6mpC/+GEAf5SqvAk8T5lFr/Ms08DeBqjMDpniw7Pzg7OfAekpGu9s5jkSbeokJtLZuqL3Q5rC9PhMu/P+n/ciDU4iWBUKSjnUymGmDs7n8ujoH4G9JuhJ57Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734017717; c=relaxed/simple; bh=tP/SfBgC81tfTdoQueFknx+548zmZ3tJisEU4UZ9RAk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IOx2bfSr8av5dwQkhguFnS1aolpmYJd+KFBxjALuVW1fsyA3Svazh54eZVddJbQjBBdlmHgVdbIZqFbx3jQy4f9nsTMBbcJF7udHCSVlVv37e8uCktWjDaMGrPTyQGUl+7rCUuX2JDT/T/tI2KPnsS6ZoTN8ORR63/+jAKV3Igo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pCjT5bnY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pCjT5bnY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0614C4CED0; Thu, 12 Dec 2024 15:35:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734017717; bh=tP/SfBgC81tfTdoQueFknx+548zmZ3tJisEU4UZ9RAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pCjT5bnYCVFDqiXc4SDC7TDH6v1/wFkiIPwLhCz6rc5soIrYfKYWieTCkj5pI9OqF 2NsLwIpQuthbWhtNZ5JNyUwNB722v9C9mAgrWn/gcoz7kZxz90EL9yGeupdd5Z/AMa sEc68jw8BGWi7nzHyy38+Xhy3+7RHMZk/NgHBoY8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Prakash Gupta , Pratyush Brahma , Will Deacon , Robin Murphy Subject: [PATCH 6.6 090/356] iommu/arm-smmu: Defer probe of clients after smmu device bound Date: Thu, 12 Dec 2024 15:56:49 +0100 Message-ID: <20241212144248.172100215@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144244.601729511@linuxfoundation.org> References: <20241212144244.601729511@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pratyush Brahma commit 229e6ee43d2a160a1592b83aad620d6027084aad upstream. Null pointer dereference occurs due to a race between smmu driver probe and client driver probe, when of_dma_configure() for client is called after the iommu_device_register() for smmu driver probe has executed but before the driver_bound() for smmu driver has been called. Following is how the race occurs: T1:Smmu device probe T2: Client device probe really_probe() arm_smmu_device_probe() iommu_device_register() really_probe() platform_dma_configure() of_dma_configure() of_dma_configure_id() of_iommu_configure() iommu_probe_device() iommu_init_device() arm_smmu_probe_device() arm_smmu_get_by_fwnode() driver_find_device_by_fwnode() driver_find_device() next_device() klist_next() /* null ptr assigned to smmu */ /* null ptr dereference while smmu->streamid_mask */ driver_bound() klist_add_tail() When this null smmu pointer is dereferenced later in arm_smmu_probe_device, the device crashes. Fix this by deferring the probe of the client device until the smmu device has bound to the arm smmu driver. Fixes: 021bb8420d44 ("iommu/arm-smmu: Wire up generic configuration support") Cc: stable@vger.kernel.org Co-developed-by: Prakash Gupta Signed-off-by: Prakash Gupta Signed-off-by: Pratyush Brahma Link: https://lore.kernel.org/r/20241004090428.2035-1-quic_pbrahma@quicinc.com [will: Add comment] Signed-off-by: Will Deacon [rm: backport for context conflict prior to 6.8] Signed-off-by: Robin Murphy Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/arm/arm-smmu/arm-smmu.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1359,6 +1359,17 @@ static struct iommu_device *arm_smmu_pro goto out_free; } else if (fwspec && fwspec->ops == &arm_smmu_ops) { smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode); + + /* + * Defer probe if the relevant SMMU instance hasn't finished + * probing yet. This is a fragile hack and we'd ideally + * avoid this race in the core code. Until that's ironed + * out, however, this is the most pragmatic option on the + * table. + */ + if (!smmu) + return ERR_PTR(dev_err_probe(dev, -EPROBE_DEFER, + "smmu dev has not bound yet\n")); } else { return ERR_PTR(-ENODEV); }