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From: Joerg Roedel <joro@8bytes.org>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	kvm@vger.kernel.org
Subject: BUG: unable to handle kernel paging request with v4.3-rc4
Date: Fri, 9 Oct 2015 16:58:27 +0200	[thread overview]
Message-ID: <20151009145827.GB27420@8bytes.org> (raw)

Hi Alex,

while playing around with attaching a 32bit PCI device to a guest via
VFIO I triggered this oops:

[  192.289917] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
[  192.298245] BUG: unable to handle kernel paging request at ffff880224582608
[  192.306195] IP: [<ffff880224582608>] 0xffff880224582608
[  192.312302] PGD 2026067 PUD 2029067 PMD 80000002244001e3 
[  192.318589] Oops: 0011 [#1] PREEMPT SMP 
[  192.323363] Modules linked in: kvm_amd kvm vfio_pci vfio_iommu_type1 vfio_virqfd vfio bnep bluetooth rfkill iscsi_ibft iscsi_boot_sysfs af_packet snd_hda_codec_via snd_hda_codec_generic snd_hda_codec_hdmi raid1 snd_hda_intel crct10dif_pclmul crc32_pclmul snd_hda_codec crc32c_intel ghash_clmulni_intel snd_hwdep snd_hda_core snd_pcm snd_timer aesni_intel aes_x86_64 md_mod glue_helper lrw gf128mul ablk_helper be2net snd serio_raw cryptd sp5100_tco pcspkr xhci_pci vxlan ip6_udp_tunnel fam15h_power sky2 udp_tunnel xhci_hcd soundcore dm_mod k10temp i2c_piix4 shpchp wmi acpi_cpufreq asus_atk0110 button processor ata_generic firewire_ohci firewire_core ohci_pci crc_itu_t radeon i2c_algo_bit drm_kms_helper pata_jmicron syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm sg [last unloaded: kvm]
[  192.399986] CPU: 4 PID: 2037 Comm: qemu-system-x86 Not tainted 4.3.0-rc4+ #4
[  192.408260] Hardware name: System manufacturer System Product Name/Crosshair IV Formula, BIOS 3027    10/28/2011
[  192.419746] task: ffff880223e24040 ti: ffff8800cae5c000 task.ti: ffff8800cae5c000
[  192.428506] RIP: 0010:[<ffff880224582608>]  [<ffff880224582608>] 0xffff880224582608
[  192.437376] RSP: 0018:ffff8800cae5fe58  EFLAGS: 00010286
[  192.443940] RAX: ffff8800cb3c8800 RBX: ffff8800cba55800 RCX: 0000000000000004
[  192.452370] RDX: 0000000000000004 RSI: ffff8802233e7887 RDI: 0000000000000001
[  192.460796] RBP: ffff8800cae5fe98 R08: 0000000000000ff8 R09: 0000000000000008
[  192.469145] R10: 000000000001d300 R11: 0000000000000000 R12: ffff8800cba55800
[  192.477584] R13: ffff8802233e7880 R14: ffff8800cba55830 R15: 00007fff43b30b50
[  192.486025] FS:  00007f94375b2c00(0000) GS:ffff88022ed00000(0000) knlGS:0000000000000000
[  192.495445] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  192.502481] CR2: ffff880224582608 CR3: 00000000cb9d9000 CR4: 00000000000406e0
[  192.510850] Stack:
[  192.514094]  ffffffffa03f9733 0000000100000000 0000000000000001 ffff880223c74600
[  192.522876]  ffff8800ca4f6d88 00007fff43b30b50 0000000000003b6a 00007fff43b30b50
[  192.531582]  ffff8800cae5ff08 ffffffff811efc7d ffff8800cae5fec8 ffff880223c74600
[  192.540439] Call Trace:
[  192.544145]  [<ffffffffa03f9733>] ? vfio_group_fops_unl_ioctl+0x253/0x410 [vfio]
[  192.552898]  [<ffffffff811efc7d>] do_vfs_ioctl+0x2cd/0x4c0
[  192.559713]  [<ffffffff811f9687>] ? __fget+0x77/0xb0
[  192.565998]  [<ffffffff811efee9>] SyS_ioctl+0x79/0x90
[  192.572373]  [<ffffffff81001bb0>] ? syscall_return_slowpath+0x50/0x130
[  192.580258]  [<ffffffff8167f776>] entry_SYSCALL_64_fastpath+0x16/0x75
[  192.588049] Code: 88 ff ff d8 25 58 24 02 88 ff ff e8 25 58 24 02 88 ff ff e8 25 58 24 02 88 ff ff 58 a2 70 21 02 88 ff ff c0 65 39 cb 00 88 ff ff <08> 2d 58 24 02 88 ff ff 08 88 3c cb 00 88 ff ff d8 58 c1 24 02 
[  192.610309] RIP  [<ffff880224582608>] 0xffff880224582608
[  192.616940]  RSP <ffff8800cae5fe58>
[  192.621805] CR2: ffff880224582608
[  192.632826] ---[ end trace ce135ef0c9b1869f ]---

I am not sure whether this is an IOMMU or VFIO bug, have you seen
something like this before?


	Joerg


             reply	other threads:[~2015-10-09 14:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-09 14:58 Joerg Roedel [this message]
2015-10-09 15:30 ` Alex Williamson
2015-10-09 15:34   ` Joerg Roedel

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