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 D77461F9EA5 for ; Fri, 6 Dec 2024 10:15:50 +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=1733480150; cv=none; b=jgHUZXE+GsZrcn3wM0H70yzvZ/N55LXyEBvbb320pgqUdJifzesvIjatZZOAWEt8lPuoOpJ4ie1pnGvc9WqxIQ0afpPtaP62FEu8yb2JDkqzofrnCgflD7G1fbQTiMKkKDtaBjkLJ+Ric4h+Hwg3kW07lUuF7+Jp2zENH6mU7lA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733480150; c=relaxed/simple; bh=LMeR3b6KobnDOuKKZvTwB9uNRVRsQv9s+EURts66FR0=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=bBNBgGZOZRRX+ebB/JY2AWJwRq2nKFS7XL4f1DUvWOMRclgVysWOxUB5ptQB3EnkRQS980ZQKdmvLPKkoC31uWi0ESuxzPXwFYRKxYaafDSOtWMtYviVW83om/uDwPdl0DtYTnpoSlTC1m2GScAlAUwwFr1iwGN1Gpk0zxY4ORc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=C66WkPjh; 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="C66WkPjh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED814C4CED1; Fri, 6 Dec 2024 10:15:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733480150; bh=LMeR3b6KobnDOuKKZvTwB9uNRVRsQv9s+EURts66FR0=; h=Subject:To:Cc:From:Date:From; b=C66WkPjh6rS5uNJmeXcdk2FeTufk9rFZl5iVpLZ3VtbkpmWrGKF1IGCF7VC32A+Mn h5bZvxQ7QhIDJ2Vm6iQFBMC+QNVfp7+J4xwJp3rt4ByYQrTJDRSWaUaftGW3EEfQti uGWMz3KYl6yyfUAudRTKmPP7PdCu4asF53UBiYao= Subject: FAILED: patch "[PATCH] iommu/arm-smmu: Defer probe of clients after smmu device" failed to apply to 6.6-stable tree To: quic_pbrahma@quicinc.com,quic_guptap@quicinc.com,will@kernel.org Cc: From: Date: Fri, 06 Dec 2024 11:15:47 +0100 Message-ID: <2024120647-germless-tint-19f2@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 229e6ee43d2a160a1592b83aad620d6027084aad # git commit -s git send-email --to '' --in-reply-to '2024120647-germless-tint-19f2@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 229e6ee43d2a160a1592b83aad620d6027084aad Mon Sep 17 00:00:00 2001 From: Pratyush Brahma Date: Fri, 4 Oct 2024 14:34:28 +0530 Subject: [PATCH] iommu/arm-smmu: Defer probe of clients after smmu device bound 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 diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index 8321962b3714..14618772a3d6 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1437,6 +1437,17 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) goto out_free; } else { 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")); } ret = -EINVAL;