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 BF10B1FA165 for ; Fri, 6 Dec 2024 10:15:57 +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=1733480157; cv=none; b=ChcWwmfqDcYPtfkBMQfV0Y/7gsujc2y3yoDHpbDDkOcf+HIhvOzDsuolG1w1RgnSnBXPRpEKeDxygP+fpF2awkQQF6HNmPwCBwVm2znYGNnr7t0obFK4u1ysbL0A0inH8bmhALe/X0amejtdzwR1DRF1Ig1de7/pQQzDqtZTkXQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733480157; c=relaxed/simple; bh=Eb8zbG6TtanfwE1WqC5wk8OJAm8WlsLS0WT/JaMOE3M=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=IvRFCnOtg/E954sU0DEJHbbXTC+qMsUY+dEwH9arQLJy9OfyO9Xe5Ejqfm/3Qa5LH8tYVzmMNTciNNkVI7lBQ2wtlgIurcLrpGUbvjQUec17r02VWk8iuWoCo4pWB9eFVenW++1ABBC/7m8FdeXNBeonwTkwc8aT/x+PEHQDNvo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yeK9Syqp; 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="yeK9Syqp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAE7BC4CEDE; Fri, 6 Dec 2024 10:15:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733480157; bh=Eb8zbG6TtanfwE1WqC5wk8OJAm8WlsLS0WT/JaMOE3M=; h=Subject:To:Cc:From:Date:From; b=yeK9SyqpmsrWxXZpTgzzHSxSEdKp5gHAU9Wbx8e+pFm8nAAyIuhtUcS9kV7m0F8fy qB+rWRcePqDaCpQuD4c4sa2Bhbipic6UKA5Y/MDU4l8ySVYgcZlgJkQTuETNh9KsqM zmROhr2Zs8lWowUZKqkKtMKe5b+NTNldNtAv5/so= Subject: FAILED: patch "[PATCH] iommu/arm-smmu: Defer probe of clients after smmu device" failed to apply to 5.15-stable tree To: quic_pbrahma@quicinc.com,quic_guptap@quicinc.com,will@kernel.org Cc: From: Date: Fri, 06 Dec 2024 11:15:49 +0100 Message-ID: <2024120649-alphabet-nuzzle-1b71@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 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x 229e6ee43d2a160a1592b83aad620d6027084aad # git commit -s git send-email --to '' --in-reply-to '2024120649-alphabet-nuzzle-1b71@gregkh' --subject-prefix 'PATCH 5.15.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;