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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 83B54C25B75 for ; Fri, 31 May 2024 22:49:05 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.733893.1140170 (Exim 4.92) (envelope-from ) id 1sDB3F-00013Q-Kt; Fri, 31 May 2024 22:48:45 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 733893.1140170; Fri, 31 May 2024 22:48:45 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1sDB3F-00013J-IM; Fri, 31 May 2024 22:48:45 +0000 Received: by outflank-mailman (input) for mailman id 733893; Fri, 31 May 2024 22:48:44 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1sDB3E-00013B-KH for xen-devel@lists.xenproject.org; Fri, 31 May 2024 22:48:44 +0000 Received: from wfhigh2-smtp.messagingengine.com (wfhigh2-smtp.messagingengine.com [64.147.123.153]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id ec5b1f42-1f9f-11ef-90a1-e314d9c70b13; Sat, 01 Jun 2024 00:48:42 +0200 (CEST) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailfhigh.west.internal (Postfix) with ESMTP id 7095718000BA; Fri, 31 May 2024 18:48:38 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute5.internal (MEProxy); Fri, 31 May 2024 18:48:38 -0400 Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 31 May 2024 18:48:36 -0400 (EDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: ec5b1f42-1f9f-11ef-90a1-e314d9c70b13 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=fm1; t=1717195718; x=1717282118; bh=xBqG5KeyHw6loZw0/cyADHLe7k/DxHhcD0woNr8hcJM=; b= rx9u5Qp02zYTx6ZIMxPXsbNxEH6kV5FDLGJ+kpgezKK3bf/3WXtF205FFj4sChwG dhzSis//Zktvmiie9lDbiHaCafj1UXUJMWM3EyuQ82jhzjx2c7vaC8O/dxZdfjG8 5msK8j56il9t4jc0iP/EQ41Wt659h9bssY7vsKi05GHaXrJ3YpkNUs9fp5vtxfLw Kwfh3kdEbgu4pO/R/G3HO/YLaQkClWXQOAbs3FEqAVnmGvFeRJU2dnkNWEio0XWP aiBimquILN4flQ7Xf56zln3/pvkklm8hd9S1Y6hv1Ho6xJUHHb2MMFpjlMv4rU8x FgpNDkb96/GoOHvpaXRxuA== 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-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm1; t=1717195718; x=1717282118; bh=xBqG5KeyHw6loZw0/cyADHLe7k/D xHhcD0woNr8hcJM=; b=oU2Qun8Wz3C+AVTKd/Kx0pvKv+XFaWc1n/fobD2akB6Y UEZNHy2n0/CVgIuXtKZUur4+3KPW8hVJujbbmE/GXhNEtKhtudUOrBCmQHo0UvD2 grw3sVONIvhl18h3+DGqy85e7dcnbG4B56Mbl1fdyE1mLBPvSftbSJY2q+X+9sBC wXDREWoqmcjuKUWwq9vcSk9sHzw0bHVh9X3AqTjkN+rdj0FgVonf3PnP3D+Y6QkV gjADxry3b0tW4Z7mByUB72mTuR3qweTJjn8KKeNAwX5FN/SKJQX1RY3CCQjykxfV Oscm21Lv1xxQfnfSse7Z0MMHnf1pwXxkueafQU5XjQ== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvledrvdekjedgudegucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvfevuffkfhggtggujgesghdtroertddtjeenucfhrhhomhepofgrrhgv khcuofgrrhgtiiihkhhofihskhhiqdfikphrvggtkhhiuceomhgrrhhmrghrvghksehinh hvihhsihgslhgvthhhihhnghhslhgrsgdrtghomheqnecuggftrfgrthhtvghrnhepheeh ueektedufeelvddvffeghedtjeeludehffeuuddugfettdelvdffjeduheevnecuffhomh grihhnpehophgvnhhsuhhsvgdrohhrghdpqhhusggvshdqohhsrdhorhhgpdhgihhthhhu sgdrtghomhenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhroh hmpehmrghrmhgrrhgvkhesihhnvhhishhisghlvghthhhinhhgshhlrggsrdgtohhm X-ME-Proxy: Feedback-ID: i1568416f:Fastmail Date: Sat, 1 Jun 2024 00:48:33 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Julien Grall Cc: xen-devel , Juergen Gross Subject: Re: NULL pointer dereference in xenbus_thread->... Message-ID: References: <0f8c0e27-e60d-4e64-bc8a-6cb407c67ab2@xen.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="4ybz0eHqAMeE41R+" Content-Disposition: inline In-Reply-To: <0f8c0e27-e60d-4e64-bc8a-6cb407c67ab2@xen.org> --4ybz0eHqAMeE41R+ Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Sat, 1 Jun 2024 00:48:33 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Julien Grall Cc: xen-devel , Juergen Gross Subject: Re: NULL pointer dereference in xenbus_thread->... On Tue, Mar 26, 2024 at 11:00:50AM +0000, Julien Grall wrote: > Hi Marek, >=20 > +Juergen for visibility >=20 > When sending a bug report, I would suggest to CC relevant people as > otherwise it can get lost (not may people monitors Xen devel if they are = not > CCed). >=20 > Cheers, >=20 > On 25/03/2024 16:17, Marek Marczykowski-G=C3=B3recki wrote: > > On Sun, Oct 22, 2023 at 04:14:30PM +0200, Marek Marczykowski-G=C3=B3rec= ki wrote: > > > On Mon, Aug 28, 2023 at 11:50:36PM +0200, Marek Marczykowski-G=C3=B3r= ecki wrote: > > > > Hi, > > > >=20 > > > > I've noticed in Qubes's CI failure like this: > > > >=20 > > > > [ 871.271292] BUG: kernel NULL pointer dereference, address: 00000= 00000000000 > > > > [ 871.275290] #PF: supervisor read access in kernel mode > > > > [ 871.277282] #PF: error_code(0x0000) - not-present page > > > > [ 871.279182] PGD 106fdb067 P4D 106fdb067 PUD 106fdc067 PMD 0 > > > > [ 871.281071] Oops: 0000 [#1] PREEMPT SMP NOPTI > > > > [ 871.282698] CPU: 1 PID: 28 Comm: xenbus Not tainted 6.1.43-1.qub= es.fc37.x86_64 #1 > > > > [ 871.285222] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996= ), BIOS rel-1.16.0-0-gd239552-rebuilt.opensuse.org 04/01/2014 > > > > [ 871.288883] RIP: e030:__wake_up_common+0x4c/0x180 > > > > [ 871.292838] Code: 24 0c 89 4c 24 08 4d 85 c9 74 0a 41 f6 01 04 0= f 85 a3 00 00 00 48 8b 43 08 4c 8d 40 e8 48 83 c3 08 49 8d 40 18 48 39 c3 7= 4 5b <49> 8b 40 18 31 ed 4c 8d 70 e8 45 8b 28 41 f6 c5 04 75 5f 49 8b 40 > > > > [ 871.299776] RSP: e02b:ffffc900400f7e10 EFLAGS: 00010082 > > > > [ 871.301656] RAX: 0000000000000000 RBX: ffff88810541ce98 RCX: 000= 0000000000000 > > > > [ 871.304255] RDX: 0000000000000001 RSI: 0000000000000003 RDI: fff= f88810541ce90 > > > > [ 871.306714] RBP: ffffc900400f0280 R08: ffffffffffffffe8 R09: fff= fc900400f7e68 > > > > [ 871.309937] R10: 0000000000007ff0 R11: ffff888100ad3000 R12: fff= fc900400f7e68 > > > > [ 871.312326] R13: 0000000000000000 R14: 0000000000000000 R15: 000= 0000000000000 > > > > [ 871.314647] FS: 0000000000000000(0000) GS:ffff88813ff00000(0000= ) knlGS:0000000000000000 > > > > [ 871.317677] CS: 10000e030 DS: 0000 ES: 0000 CR0: 00000000800500= 33 > > > > [ 871.319644] CR2: 0000000000000000 CR3: 00000001067fe000 CR4: 000= 0000000040660 > > > > [ 871.321973] Call Trace: > > > > [ 871.322782] > > > > [ 871.323494] ? show_trace_log_lvl+0x1d3/0x2ef > > > > [ 871.324901] ? show_trace_log_lvl+0x1d3/0x2ef > > > > [ 871.326310] ? show_trace_log_lvl+0x1d3/0x2ef > > > > [ 871.327721] ? __wake_up_common_lock+0x82/0xd0 > > > > [ 871.329147] ? __die_body.cold+0x8/0xd > > > > [ 871.330378] ? page_fault_oops+0x163/0x1a0 > > > > [ 871.331691] ? exc_page_fault+0x70/0x170 > > > > [ 871.332946] ? asm_exc_page_fault+0x22/0x30 > > > > [ 871.334454] ? __wake_up_common+0x4c/0x180 > > > > [ 871.335777] __wake_up_common_lock+0x82/0xd0 > > > > [ 871.337183] ? process_writes+0x240/0x240 > > > > [ 871.338461] process_msg+0x18e/0x2f0 > > > > [ 871.339627] xenbus_thread+0x165/0x1c0 > > > > [ 871.340830] ? cpuusage_read+0x10/0x10 > > > > [ 871.342032] kthread+0xe9/0x110 > > > > [ 871.343317] ? kthread_complete_and_exit+0x20/0x20 > > > > [ 871.345020] ret_from_fork+0x22/0x30 > > > > [ 871.346239] > > > > [ 871.347060] Modules linked in: snd_hda_codec_generic ledtrig_aud= io snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec snd_hda_= core snd_hwdep snd_seq snd_seq_device joydev snd_pcm intel_rapl_msr ppdev i= ntel_rapl_common snd_timer pcspkr e1000e snd soundcore i2c_piix4 parport_pc= parport loop fuse xenfs dm_crypt crct10dif_pclmul crc32_pclmul crc32c_inte= l polyval_clmulni polyval_generic floppy ghash_clmulni_intel sha512_ssse3 s= erio_raw virtio_scsi virtio_console bochs xhci_pci xhci_pci_renesas xhci_hc= d qemu_fw_cfg drm_vram_helper drm_ttm_helper ttm ata_generic pata_acpi xen_= privcmd xen_pciback xen_blkback xen_gntalloc xen_gntdev xen_evtchn scsi_dh_= rdac scsi_dh_emc scsi_dh_alua uinput dm_multipath > > > > [ 871.368892] CR2: 0000000000000000 > > > > [ 871.370160] ---[ end trace 0000000000000000 ]--- > > > > [ 871.371719] RIP: e030:__wake_up_common+0x4c/0x180 > > > > [ 871.373273] Code: 24 0c 89 4c 24 08 4d 85 c9 74 0a 41 f6 01 04 0= f 85 a3 00 00 00 48 8b 43 08 4c 8d 40 e8 48 83 c3 08 49 8d 40 18 48 39 c3 7= 4 5b <49> 8b 40 18 31 ed 4c 8d 70 e8 45 8b 28 41 f6 c5 04 75 5f 49 8b 40 > > > > [ 871.379866] RSP: e02b:ffffc900400f7e10 EFLAGS: 00010082 > > > > [ 871.381689] RAX: 0000000000000000 RBX: ffff88810541ce98 RCX: 000= 0000000000000 > > > > [ 871.383971] RDX: 0000000000000001 RSI: 0000000000000003 RDI: fff= f88810541ce90 > > > > [ 871.386235] RBP: ffffc900400f0280 R08: ffffffffffffffe8 R09: fff= fc900400f7e68 > > > > [ 871.388521] R10: 0000000000007ff0 R11: ffff888100ad3000 R12: fff= fc900400f7e68 > > > > [ 871.390789] R13: 0000000000000000 R14: 0000000000000000 R15: 000= 0000000000000 > > > > [ 871.393101] FS: 0000000000000000(0000) GS:ffff88813ff00000(0000= ) knlGS:0000000000000000 > > > > [ 871.395671] CS: 10000e030 DS: 0000 ES: 0000 CR0: 00000000800500= 33 > > > > [ 871.397863] CR2: 0000000000000000 CR3: 00000001067fe000 CR4: 000= 0000000040660 > > > > [ 871.400441] Kernel panic - not syncing: Fatal exception > > > > [ 871.402171] Kernel Offset: disabled > > > > (XEN) Hardware Dom0 crashed: rebooting machine in 5 seconds. > > > >=20 > > > > It isn't the first time I see similar crash, but I can't really > > > > reproduce it reliably. Restarted test usually passes. > > > > Note this is Xen nested in KVM, so it could very well be some oddity > > > > about nested virt, although looking at the stack trace, it's unlike= ly > > > > and more likely some race condition hit only on slower system. > > >=20 > > > Recently I've got the same crash on a real system in domU too. And al= so > > > on nested on newer kernel 6.1.57 (here it happened in dom0). So, this= is > > > still an issue and affects not only nested case :/ > > >=20 > > > > Unfortunately I don't have symbols for this kernel handy, but there= is a > > > > single wake_up() call in process_writes(), so it shouldn't be an is= sue. > > > >=20 > > > > Any ideas? > > > >=20 > > > > Full log at https://openqa.qubes-os.org/tests/80779/logfile?filenam= e=3Dserial0.txt > > >=20 > > > More links at https://github.com/QubesOS/qubes-issues/issues/8638, > > > including more recent stack trace. > >=20 > > Happens on 6.1.75 too (new stack trace I've added to the issue above, > > but it's pretty similar). Recently I've got a report from another user about similar issue, on 6.6.29 this time. I also still encounter this issue once a month or so, but the user claims they get it much more often: https://github.com/QubesOS/qubes-issues/issues/8638#issuecomment-2135419896 The extra conditions reported by the user are: - old AMD system (KGPE-D16 with Opteron 6282 SE) requiring `spec-ctrl=3Dibpb-entry=3Dno-pv` to remain usable=20 - Whonix domU, which has a bunch of sysctl parameters changed, listed at: - https://github.com/Kicksecure/security-misc - https://github.com/Kicksecure/security-misc/blob/master/usr/lib/sysctl.= d/990-security-misc.conf (unsure which are relevant, maybe `vm.swappiness=3D1`?) --=20 Best Regards, Marek Marczykowski-G=C3=B3recki Invisible Things Lab --4ybz0eHqAMeE41R+ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmZaU8EACgkQ24/THMrX 1yzlBQf/U9j0tGuo4A2afz3xwZ7iglL8ZWb6RE7/XS33u15Be96Zpbi4LkzVEXAl lz9Qyl1wbS3OHMvXeuv+HerZWNXIWOe6lqIonlQBlrFkJn/aC7QHhh0BGb1+S1i9 0DcPMjtxVTfzBDBD6qSi3WlkQgr+GKSChxUqYCAQiQTBzQOrZj9V5AlK4uXSTj+T E4hxGJRQO229qfFPe81C1SSTUhJ72Y+kcfFvagKRveHxRoJLas1sq82G9v42w5dt I3rxLAQwrWfTuAQtnl3LrPYUvqIK473AS3J/TGlWv4fUJsyWr+F6Sg+jw21sIXoZ GrQNSzqTh6+FubfuZmLmZw/64yX4TQ== =l/kf -----END PGP SIGNATURE----- --4ybz0eHqAMeE41R+--