From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fout-b5-smtp.messagingengine.com (fout-b5-smtp.messagingengine.com [202.12.124.148]) (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 5FDCC3BFAFC for ; Fri, 5 Jun 2026 22:40:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.12.124.148 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780699225; cv=none; b=BKTEcheF0Y0zZ5si0VjKjrWfzuOx0LAKWJS8vIqZynKylC/d0AUv5oLD9Mzq74vIuVI/rqVRMDJcKFurkWrmoExR6xStrTGPVMBoDytc4BHk51aHAqFW5y3Z0v/eH9I3JXOm732L/9G7opXJhkOxpuKdiaC5DqnFrEHJMY1VPiY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780699225; c=relaxed/simple; bh=0mYlsnhwu0+mEjshhzrYaxFcuYcNj9o/xbk/25egxoE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BI0ACfXt7jTHQLut/ODuBPB3H632EOYnZT8M7t2wQxQXusY1cNnKn46HgA8VSDcKNBAgLvij2Zge9vwVgXb36F5Qi7Br3LyWQoHgYtAssVCsu6WgtaJ0CgJ81H2pjosCnKb71F6PhZX16L+lvsmfUm3E0ysZFtJb79hPxgh0Lr4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=invisiblethingslab.com; spf=pass smtp.mailfrom=invisiblethingslab.com; dkim=pass (2048-bit key) header.d=invisiblethingslab.com header.i=@invisiblethingslab.com header.b=WInalkAQ; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=LyiKmMRq; arc=none smtp.client-ip=202.12.124.148 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=invisiblethingslab.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=invisiblethingslab.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=invisiblethingslab.com header.i=@invisiblethingslab.com header.b="WInalkAQ"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="LyiKmMRq" Received: from phl-compute-05.internal (phl-compute-05.internal [10.202.2.45]) by mailfout.stl.internal (Postfix) with ESMTP id 9EAE81D0012D; Fri, 5 Jun 2026 18:40:23 -0400 (EDT) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-05.internal (MEProxy); Fri, 05 Jun 2026 18:40:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= invisiblethingslab.com; h=cc:cc:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to; s=fm3; t=1780699223; x=1780785623; bh=yQKtsKdHTEeGy+wBb5lviK3laL978h18PIXdo6tNDuc=; b= WInalkAQnODxZVLNTgBeP71AcMq1ctdsJ9JaIQwE6Fq72f71cqDBxQsfymOWklti Id4cxVTe46MiYVIa8VTLTQxNGnvzMVryKoMrF6lBIQ4fcjxROfVlNUQNBnfPJZhF I4Gs9uoFYEjM6HMqJxaayjV+9hlzaDsdlBRjQD/jzXX+vwEsOfHAvCUDmDijW5tV yiuwgieLByHEYWuV1zy5vNgVDIgbzUSyL5g/eBaksShNSdyv3/XqRu6MfjzBHKx1 bluwDMWkBRH1JUB5fWB+Sdezczo9CXK9Grv/XkKUkI6e3z8v5QoWaBFERhxagWv1 y1Y0HtZEryd6f+rSzFUaQg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; t= 1780699223; x=1780785623; bh=yQKtsKdHTEeGy+wBb5lviK3laL978h18PIX do6tNDuc=; b=LyiKmMRq6nbH6HrSO8Dh56BclAKfuXL77T+PwAFZpXDTQya2Wyy 45SbAi5/9JRgiydHgB90S6TNU971EtQ9Woe4oUInof8vd04i3C9XTF11oNbqpcRV vdoOKly+fgmTcs+kcf5zpPiMCVN2FUk+tb30rxuzKpu9B1zXD7ARzZkfEBDByBZQ kMyJlOAFNGUTcDPqLhieZHz9aNYRUqe6ybbakso6cnaKFub1ewhb7TCJOzYQ4ncl +IF6+bJ/T6LWVEvpJiOYwrqwww3HyK/Akew02T36qjJVRbyDHHWJsvvsr+rAE2u9 e+Zo4LC/YmHwwO5PI5hYDUPefg7oqLwTNcg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTGWJCuU/pZQJEZTt8f57xCxq8G+d/Rk4uxFup/BC+yeQwILaA/kECNUFzhUOn5+Y+ jaLsZiPm8G1lAVWJYWxHmzHusPgHUKhiAHEbp9ObGhHlbWKIg9EBgaf8FH47IZxylRhc2Z Ab4ERpobkBofgbcrZXyFsNSWH+3W54Qdz9pRFiQsZigdVSmeg68VBldR592vnwuJO+4VBD LXbauIlcHFofBrotAYo9Y+OHsG93gykQn3Pj2YJCfJpA2GZaQlMYmpIMrRT3fjVCYpBKFl UnRn1oVYC/isv6R3zSVfx9hNsNTFGul+A/n5VCjzW4RxYNwUrDoU90O3POa3LcFyTaNDNx JXr+6OjEoH1bg1nIuM30eZuoJy2O8WlMGc2xQQ2hlV+lal/zA6jKk0MQouanNK9TbwRUN/ +p9yRHpz3iL755f+4wUpqFhDcq6dMNcoZGXOsQ+uvoyGncEr6BOxRXoNQHTtFmSmbMWnnq Kr0gSCpWzKovErgsA9s3cCf6Q4E6Ke372OekXd33ngyppco16Wsmb+/eBhbYvhhNqwgVXK nLraaOf8h4YX7jboUXlL8nyyXxZTDLIQnI4bSsjQAPOmHru/MMaM8NP1ow2UQvxCQnl2Zj 6NLoEBEXhyesTm9CfYmayjjSiOKfeOk967Mssq1uaWqYoF2q24A4KcHHGcrw X-ME-Proxy: Feedback-ID: i1568416f:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 5 Jun 2026 18:40:21 -0400 (EDT) Date: Sat, 6 Jun 2026 00:40:20 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Borislav Petkov Cc: Mario Limonciello , Yazen Ghannam , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "open list:AMD NODE DRIVER" , regressions@lists.linux.dev Subject: Re: kernel NULL pointer dereference in quirk_clear_strap_no_soft_reset_dev2_f0 -> amd_smn_read Message-ID: References: <68d86871-12f2-4de1-81aa-dbc9e12b6f91@amd.com> <2535f876-adea-41f1-bf92-a2f15a1eb157@amd.com> <20260605211543.GFaiM8f2Ee2r5hMYXW@fat_crate.local> <20260605222648.GAaiNNKAr3mtWsMr7e@fat_crate.local> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="PvbObVgcOlmlUPOG" Content-Disposition: inline In-Reply-To: <20260605222648.GAaiNNKAr3mtWsMr7e@fat_crate.local> --PvbObVgcOlmlUPOG Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Sat, 6 Jun 2026 00:40:20 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Borislav Petkov Cc: Mario Limonciello , Yazen Ghannam , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "open list:AMD NODE DRIVER" , regressions@lists.linux.dev Subject: Re: kernel NULL pointer dereference in quirk_clear_strap_no_soft_reset_dev2_f0 -> amd_smn_read On Fri, Jun 05, 2026 at 03:26:48PM -0700, Borislav Petkov wrote: > On Fri, Jun 05, 2026 at 11:55:47PM +0200, Marek Marczykowski-G=C3=B3recki= wrote: > > Well, it clearly happens, see the call trace in the first message of the > > thread... > > Do you suggest the fix should change > > quirk_clear_strap_no_soft_reset_dev2_f0()? >=20 > https://lore.kernel.org/all/20260602184823.GKah8ld2QJLm28xoa9@fat_crate.l= ocal/ >=20 > That thing should return an error so that amd_smn_read() is not even avai= lable > on guests. What do you mean by "not even available on guests"? I'm talking about https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arc= h/x86/pci/fixup.c#n876 static void quirk_clear_strap_no_soft_reset_dev2_f0(struct pci_dev *dev) { u32 data; if (!amd_smn_read(0, AMD_15B8_RCC_DEV2_EPF0_STRAP2, &data)) { data &=3D ~AMD_15B8_RCC_DEV2_EPF0_STRAP2_NO_SOFT_RESET_DEV2_F0_= MASK; if (amd_smn_write(0, AMD_15B8_RCC_DEV2_EPF0_STRAP2, data)) pci_err(dev, "Failed to write data 0x%x\n", data); } else { pci_err(dev, "Failed to read data\n"); } } DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x15b8, quirk_clear_strap_no= _soft_reset_dev2_f0); There is nothing here that would prevent amd_smn_read() being called inside a guest... --=20 Best Regards, Marek Marczykowski-G=C3=B3recki Invisible Things Lab --PvbObVgcOlmlUPOG Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmojUFQACgkQ24/THMrX 1yyWlAgAiccjo553UfT+FGtfbu8EqSLSqOG6HQ3UKXHL7RMJTudc7nerYKj+v1Jm ByLOtNslDoVkj66XXU9vh5bexRltovgM5ETnxi3nXHnAbXKfeSMLFAzy5dk0h/Wv xqZdxBR+OsxyUWaFueC3e15Um2kRCAvzVjsJM6D2OKG5Q5CGSiRrc1kGvVwqiXF/ fJ+qORbwilU77RJEhRgwgnv9SKansS7hx3yFUIDAcWdInOw5gIeSVnyKWxhWjG08 DYpssK0HXKMIr7k4l5E8RNod/mwGmztyZft+hr3/+PbhOCCorKYQPbu/iNvO4OcK M8BwHJ2oTHs4L1EG9ko7cNJmIqcG6A== =dkI0 -----END PGP SIGNATURE----- --PvbObVgcOlmlUPOG--