From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 0F99444103D; Tue, 9 Jun 2026 15:01:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781017306; cv=none; b=BZfA0dhCZeUJtsDVDcX/ZvuHJlyU1XJIyfNWy7wAQry/QfylXLaBqvafp4Q98VcEkyX22ajSngERCTpSAXNHMLkotN+vwENaYN8W0h83wQLfeVytWBhCbA581RKFfw4hjWOan5Au5ewBp3WXxxr0z3kXGWFRVLPtnpdwySFaQB8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781017306; c=relaxed/simple; bh=YhUDe3k3TPbDblHXOz10uYYz87OG3gNxI9eWO7GwEEE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=XJWmWCz67eOO7nNdGTumSKU1jlhSEwfHQ3JL7J13dv4Jozev00z0Pg7UJokrXjfSI+ua7JGOnEKaunkwvMCORx18PDRxvw7WrNrpg5+KVAawShbQSJD3PoCtE3jTe5O4lKsr4c8a9bMdov7ClKsuPLyRitDfHtozaw1SDOvPRaE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gVkP8Gh/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gVkP8Gh/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE7B51F00893; Tue, 9 Jun 2026 15:01:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781017303; bh=ZJNNjx5rPNQjNigmmu6Xw22uEYkdyohNUuF5z4+RY4Y=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=gVkP8Gh/kgmmCLDYq9pwbRaToBEiyMvnKFiyHVeuc6hqVecV+t/ImNuS6/l7wCZUE dBXyeCiLRD64h7XuTF9ra1ENbpDGVuSkqmsIyuNkvoevM4PRih76ttLcAPF0y9xDj9 EvoOT1PNifR9O/RVxlVjStXkI/u4XkNA7tGyHwzzsOisCIL/TJ9BBzKil4TN85EeSM vlQBElt6kHQ0+e21WGWMIJq1s1uvoqyu+lif/LRdIXP0puIPHZiIQpePVVbbxDYF7h qgz0AFCivl5LUJ6Kz0/0sXiXqVbzKRvM3EBevCjEnXhfLP74xMw33A9sxoIoXoMZmx dUF1C19j/HyYw== Message-ID: <31cba498-24c9-4d73-bb17-bba9cf730b55@kernel.org> Date: Tue, 9 Jun 2026 17:01:37 +0200 Precedence: bulk X-Mailing-List: linux-tegra@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/3] memory: tegra186-emc: stop borrowing MC aggregate hook for EMC To: Sumit Gupta , treding@nvidia.com, jonathanh@nvidia.com, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org Cc: bbasu@nvidia.com References: <20260527140127.49172-1-sumitg@nvidia.com> <20260527140127.49172-2-sumitg@nvidia.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 27/05/2026 16:01, Sumit Gupta wrote: > tegra186_emc_interconnect_init() copies the MC's ICC aggregate hook > into the EMC provider. That hook (tegra234_mc_icc_aggregate / > tegra264_mc_icc_aggregate) uses container_of() to recover 'mc', > which is only valid when the icc_provider is embedded in struct > tegra_mc. For an EMC node the provider is embedded in struct > tegra186_emc, so 'mc' points into unrelated memory. > > This stayed harmless until commit faafd6ca7e6e ("memory: tegra: > make icc_set_bw return zero if BWMGR not supported") added an > unconditional read of mc->bwmgr_mrq_supported at the top of the > hook. UBSAN catches the stray load on every EMC aggregation: > > UBSAN: invalid-load in drivers/memory/tegra/tegra234.c:1104:9 > load of value 112 is not a valid value for type '_Bool' > > No functional impact in practice, since the hook's only other mc > dereference (mc->num_channels) sits inside a > TEGRA_ICC_MC_CPU_CLUSTER* branch that EMC nodes never enter. > > Fix this by setting the EMC provider's aggregate hook to > icc_std_aggregate, instead of borrowing the MC's hook. The MC > providers continue using their own aggregate hooks, where > container_of() correctly resolves to struct tegra_mc. > > Reported-by: Jon Hunter I assume these reports were offlist. Otherwise this has a valid checkpatch warning. Best regards, Krzysztof