From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (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 29A94367B8A; Fri, 11 Sep 2026 14:58:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789138684; cv=none; b=o6if+16K3Ek/fdppSZuVK51NkvNHQ1gmdqIOGMI26gKA5l8LbsOb/p37iw5+WhNpkn0Q3iuLUajXyTH0NZSuZFK2OspF/Swfq9B2PJ1O2Rwj1RrwCw3Gj+cZQWIEY5J117pBTMfIYli3or7vj4CAdlcBFDiMzPn2xpbbst3JYxg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789138684; c=relaxed/simple; bh=sWJ9/QLmlJdH1a4A4ox4tvmelMsF0lXR1XmcXFxvJXY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=S9y7hOSluJ+cu5V/xOBoS+Kbw4mXTlwcNLA0j5iA5b5HjgAl26pUb7ZFxxxEYRE0HJsM8Nhq0a/bNcQsw9wzz7kOr8sDGkE+3JIm+tjYg7dHSBO1mJU54NIy51lCc/qABlxjZQ7oJ9xn01MuK7sm6D7hbhCvfbApWws5RGpjUIU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=c4MZ28Nj; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="c4MZ28Nj" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-ID:Content-Description; bh=sWJ9/QLmlJdH1a4A4ox4tvmelMsF0lXR1XmcXFxvJXY=; b=c4MZ28NjcGLoT5gvFsqSD2qxTd JvWNXyAS12CEm6CWfG7BXBPNpC0fryaEfoHNgwjdrsSDuyKz+xMNcPZM+6KSyPeJhcr20f424vkS4 SgTiY+emYvLRLhi/z8TGHUcRPD7CvP7aE0CbO9VBmdZ3HxGv0ZCej8qCUQNMM8WAKykjDDvSk8Fmd LzdnLW9Tfv4zw6Gj/u2GgZv4KmdlZPwY/TGMXHhqwn29akk+MG5hjHhX3RxEDalhYKBXdxPKCsxvF 7OD/I/qRRe/5+AcMQ7SB7q6mINlTLpnv62Xzuu4J3Di1162En8H69+FJNKtPdfGARVplpJmuq8Uvb EO+NpenA==; Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1x52hN-001MsA-2r; Fri, 11 Sep 2026 14:57:54 +0000 Date: Fri, 11 Sep 2026 07:57:49 -0700 From: Breno Leitao To: Will Deacon , Robin Murphy , "Joerg Roedel (AMD)" , catalin.marinas@arm.com, mark.rutland@arm.com Cc: puranjay@kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, rmikey@meta.com, kernel-team@meta.com Subject: Re: [PATCH 0/2] iommu/arm-smmu-v3: SMMU hitting kdump mid-air Message-ID: References: <20260911-smmu_fix_aws-v1-0-75870bf9655b@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260911-smmu_fix_aws-v1-0-75870bf9655b@debian.org> X-Debian-User: leitao On Fri, Sep 11, 2026 at 07:54:43AM -0700, Breno Leitao wrote: > I've found that kdump does not work on some ARM host, such as AWS > Graviton metal, and the SMMU is what seems to kills it. > > The capture kernel dies about a second after it resets the SMMU, part > way through PCI enumeration, and takes the machine with it. > > There is no panic and no oops: the console stops mid-line and the box > reboots, leaving no vmcore, no log and nothing on disk. Crashes on this > hardware mostly produce no dump at all. > > This is my theory, from an "outsider view": This should really have been tagged RFC — apologies for missing that.