From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 79C50C88E58 for ; Fri, 11 Sep 2026 14:58:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sWJ9/QLmlJdH1a4A4ox4tvmelMsF0lXR1XmcXFxvJXY=; b=xust/ljBq/eK4fwCJSBHyl0tQo NeuXKb1rOZ7+YmCzR4Ij7qK4jQWEpAXi2Xhb9gGs5I/xBDb6UPLs2xItmhX1mnxkr7dWs84RJ2Do5 K7uPNojotmsSu7HYh3uQLQDEPArqY1ZaXZpNtSsD5nqQb4+38XP8EQPPYshK7zC4+g1SfJXaNXkdT iawWaJM2yC2m77OCmprzqv9YPYlYMYaP7MlfLa51mJeltMegFWBOgiUGTDAXHGV2WM56Pjh0U53xf AazgV1G/V8LeJpkyhLqy8ytrMdmfLTVpuMGyhlosY6zTN31EClKPurcoiKtLo7ILDqvCFwSvTwHBe 9Ir7ImHA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x52hV-0000000Gyjy-1TiW; Fri, 11 Sep 2026 14:58:01 +0000 Received: from stravinsky.debian.org ([2001:41b8:202:deb::311:108]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x52hT-0000000GyjW-10cu for linux-arm-kernel@lists.infradead.org; Fri, 11 Sep 2026 14:58:00 +0000 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> 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260911_075759_283364_CF1F4145 X-CRM114-Status: GOOD ( 12.59 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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.