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 865B2221FCD; Tue, 9 Jun 2026 15:08:35 +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=1781017717; cv=none; b=UsPD+DcvBbmFdKN1mAIlSWOUunQ4HzZqOmr+Sl9QwWzWgyDHDOJUsyXt/9L0rMrCmV8iSHm5PvZye8D7jdfOlJPv9G4obQ0JWYpfEzoY2lYfZHiizVyGO6PmIKYui3yqNcwoxZH63LLueZY42PP3roDX6BGXfaUU+PWJlsT11EY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781017717; c=relaxed/simple; bh=kKpG0gAhAGVntdHPD+n5ECoqxSj1x3Gfqlct2FItSP0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=b+Beb6gojIpZiDYfNfAUchpovKdH9ywhUIxgPtTwhf0G9NaEbtNJ1SKnA6gmmci083LWiMUGNx/vUMKBo22n51Fcj7rHbze744Fursh9DPcwWzrz5jPjG1uCt3oQQ3V4nQFX8pH+3AIkWnk2JgMZfJFAkJyVmjNBCRtGR8IlfeI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MLVjMV90; 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="MLVjMV90" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4B241F00893; Tue, 9 Jun 2026 15:08:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781017715; bh=zclvmjBeqhlBuxOGS6uNOQaBQOyfAdQWBrRW7MPmNyY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=MLVjMV902l5PxA+V+wj08KBxjJCaUASKjqdsHvt+RaqjIBNPydGrQcY0WKp9xkAY9 ojZnsmgn6+FjtAlCX7nzUTZ3ZPzXejDbW3GTHMc/X/kGEqhTmy4XwXlvGD/fpjMo6A z36yZeSYEw4V7sl3O/K+lBj+SFZXQeFXQ23JIwD/WT7W5WCalyCeDkPN6JYjDIV93u 6th7i7R6gQBXxD9MSEnfwfFZehEEGXH6CtLgNLwdUhjaLFl6g/HTFMxo0u7dj8pki9 r2TiuUC/Us0wKz4QVsSfUS6MNZ2EESJzdYabOEI8AY21/H13wCwZY1fgUerYPwKApR Iao/8YWT9vqwg== Message-ID: <95d51b76-bfbf-4201-94be-a8539ee4daa2@kernel.org> Date: Tue, 9 Jun 2026 17:08:28 +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: Jon Hunter , Sumit Gupta , treding@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> <31cba498-24c9-4d73-bb17-bba9cf730b55@kernel.org> <0d8f1f3b-ed7b-4066-af6e-08c006788535@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 09/06/2026 17:07, Jon Hunter wrote: > > On 09/06/2026 16:01, Krzysztof Kozlowski wrote: >> 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. > > > Yes some of our internal testing flagged this and I had asked Sumit to > take a look. > Ack, thanks! Best regards, Krzysztof