Re: [syzbot] WARNING in kvm_mmu_uninit_tdp_mmu (2)

[Maxim Levitsky]

On Sat, 2022-04-23 at 03:56 -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    59f0c2447e25 Merge tag 'net-5.18-rc4' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15a61430f00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6bc13fa21dd76a9b
> dashboard link: https://syzkaller.appspot.com/bug?extid=a8ad3ee1525a0c4b40ec
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=134363d0f00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11ed3e34f00000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+a8ad3ee1525a0c4b40ec@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 3597 at arch/x86/kvm/mmu/tdp_mmu.c:57 kvm_mmu_uninit_tdp_mmu+0xf8/0x130 arch/x86/kvm/mmu/tdp_mmu.c:57
> Modules linked in:
> CPU: 1 PID: 3597 Comm: syz-executor294 Not tainted 5.18.0-rc3-syzkaller-00060-g59f0c2447e25 #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
> RIP: 0010:kvm_mmu_uninit_tdp_mmu+0xf8/0x130 arch/x86/kvm/mmu/tdp_mmu.c:57
> Code: 83 d8 a0 00 00 48 39 c5 75 24 e8 e3 4d 5a 00 e8 9e e0 45 00 5b 5d e9 d7 4d 5a 00 e8 b2 42 a5 00 e9 3d ff ff ff e8 c8 4d 5a 00 <0f> 0b eb ad e8 bf 4d 5a 00 0f 0b eb d3 e8 c6 42 a5 00 e9 64 ff ff
> RSP: 0018:ffffc90002e37c08 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffffc90002cda000 RCX: 0000000000000000
> RDX: ffff888023f1e180 RSI: ffffffff811e1688 RDI: 0000000000000001
> RBP: ffffc90002ce40e8 R08: 0000000000000001 R09: 0000000000000001
> R10: ffffffff817ead48 R11: 0000000000000000 R12: ffffc90002cda000
> R13: ffffc90002e37c50 R14: 0000000000000003 R15: ffffc90002cdb240
> FS:  0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000560ac4d0cd68 CR3: 000000000ba8e000 CR4: 0000000000152ee0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  kvm_arch_destroy_vm+0x350/0x470 arch/x86/kvm/x86.c:11860
>  kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1230 [inline]
>  kvm_put_kvm+0x4fa/0xb70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1264
>  kvm_vm_release+0x3f/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1287
>  __fput+0x277/0x9d0 fs/file_table.c:317
>  task_work_run+0xdd/0x1a0 kernel/task_work.c:164
>  exit_task_work include/linux/task_work.h:37 [inline]
>  do_exit+0xaff/0x2a00 kernel/exit.c:795
>  do_group_exit+0xd2/0x2f0 kernel/exit.c:925
>  __do_sys_exit_group kernel/exit.c:936 [inline]
>  __se_sys_exit_group kernel/exit.c:934 [inline]
>  __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f0327505409
> Code: Unable to access opcode bytes at RIP 0x7f03275053df.
> RSP: 002b:00007ffc4a0be998 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
> RAX: ffffffffffffffda RBX: 00007f0327578350 RCX: 00007f0327505409
> RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
> RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 68742f636f72702f
> R10: 00000000ffffffff R11: 0000000000000246 R12: 00007f0327578350
> R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
>  </TASK>
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
> 
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
> 

I can reproduce this in a VM, by running and CTRL+C'in my ipi_stress test,
I am using to test AVIC, but without any relevant patches in the guest kernel.


[  304.367317] WARNING: CPU: 1 PID: 5460 at arch/x86/kvm/mmu/tdp_mmu.c:57 kvm_mmu_uninit_tdp_mmu+0x55/0x60 [kvm]
[  304.368751] Modules linked in: kvm_amd(O) ccp kvm(O) irqbypass xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT uinput snd_seq_dummy snd_hrtimer ip6table_mangle ip6table_nat ip6table_filter
ip6_tables iptable_mangle iptable_nat nf_nat bridge rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace rfkill sunrpc vfat fat snd_hda_codec_generic snd_hda_intel snd_intel_dspcfg
snd_hda_codec snd_hwdep snd_hda_core rng_core snd_seq snd_seq_device input_leds snd_pcm joydev snd_timer snd lpc_ich mfd_core virtio_input efi_pstore pcspkr rtc_cmos button sch_fq_codel ext4 mbcache
jbd2 hid_generic usbhid hid virtio_gpu virtio_dma_buf drm_shmem_helper drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops virtio_blk virtio_net drm net_failover virtio_console failover
i2c_core crc32_pclmul crc32c_intel xhci_pci xhci_hcd virtio_pci virtio virtio_pci_legacy_dev virtio_pci_modern_dev virtio_ring dm_mirror dm_region_hash dm_log fuse ipv6 autofs4 [last unloaded: ccp]
[  304.383703] CPU: 1 PID: 5460 Comm: CPU 6/KVM Tainted: G        W  O      5.18.0-rc4.unstable #5
[  304.384804] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[  304.385659] RIP: 0010:kvm_mmu_uninit_tdp_mmu+0x55/0x60 [kvm]
[  304.386302] Code: 8d 83 28 a4 00 00 48 39 c2 75 1e 48 8b 83 18 a4 00 00 48 81 c3 18 a4 00 00 48 39 d8 75 11 e8 52 d5 8d e0 48 8b 5d f8 c9 c3 90 <0f> 0b 90 eb dc 90 0f 0b 90 eb e9 0f 1f 44 00 00 55
8b 05 a0 c3 d6
[  304.388246] RSP: 0018:ffffc90003503bf0 EFLAGS: 00010293
[  304.388807] RAX: ffffc900034cb428 RBX: ffffc900034c1000 RCX: 0000000000000000
[  304.389561] RDX: ffff888120446c80 RSI: ffffffff8115e949 RDI: ffffffff81a6ee08
[  304.390315] RBP: ffffc90003503bf8 R08: 0000000000000000 R09: 0000000000000000
[  304.391078] R10: 0000000000000394 R11: 0000000000000386 R12: ffffc900034c1000
[  304.391818] R13: ffffc900034c1000 R14: ffff888113d8b728 R15: dead000000000100
[  304.392573] FS:  0000000000000000(0000) GS:ffff88846ce40000(0000) knlGS:0000000000000000
[  304.393430] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  304.394050] CR2: 0000000000000000 CR3: 0000000002c21000 CR4: 0000000000350ee0
[  304.394805] Call Trace:
[  304.395086]  <TASK>
[  304.395315]  kvm_mmu_uninit_vm+0x22/0x30 [kvm]
[  304.395821]  kvm_arch_destroy_vm+0x135/0x1c0 [kvm]
[  304.396365]  kvm_destroy_vm+0x19d/0x310 [kvm]
[  304.396858]  kvm_put_kvm+0x26/0x40 [kvm]
[  304.397390]  kvm_vm_release+0x22/0x30 [kvm]
[  304.397865]  __fput+0xa5/0x270
[  304.398207]  ____fput+0xe/0x10
[  304.398532]  task_work_run+0x61/0xb0
[  304.398913]  do_exit+0x3a9/0xb60
[  304.399286]  do_group_exit+0x3b/0xc0
[  304.399676]  get_signal+0xd9c/0xde0
[  304.400062]  arch_do_signal_or_restart+0x37/0x790
[  304.400576]  ? do_futex+0x8a/0x150
[  304.400950]  exit_to_user_mode_prepare+0x152/0x240
[  304.401603]  syscall_exit_to_user_mode+0x1f/0x60
[  304.402230]  do_syscall_64+0x44/0x80
[  304.402690]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  304.408493] RIP: 0033:0x7f593c746a8a
[  304.408887] Code: Unable to access opcode bytes at RIP 0x7f593c746a60.
[  304.409589] RSP: 002b:00007f59348ed5a0 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
[  304.410407] RAX: fffffffffffffe00 RBX: 0000000000000000 RCX: 00007f593c746a8a
[  304.411365] RDX: 0000000000000000 RSI: 0000000000000189 RDI: 000055f11c7f4fe8
[  304.411366] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000ffffffff
[  304.411367] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[  304.411368] R13: 000055f11c7f4fe8 R14: 0000000000000000 R15: 0000000000000000
[  304.411371]  </TASK>
[  304.414745] irq event stamp: 0
[  304.415086] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
[  304.415762] hardirqs last disabled at (0): [<ffffffff811339cb>] copy_process+0x94b/0x1ec0
[  304.416628] softirqs last  enabled at (0): [<ffffffff811339cb>] copy_process+0x94b/0x1ec0
[  304.417510] softirqs last disabled at (0): [<0000000000000000>] 0x0
[  304.418186] ---[ end trace 0000000000000000 ]---


Best regards,
	Maxim Levitsky