On Mon, Apr 24, 2023, Dmitry Vyukov wrote: > On Fri, 21 Apr 2023 at 23:52, 'Sean Christopherson' via syzkaller-bugs > <syzkaller-bugs@xxxxxxxxxxxxxxxx> wrote: > > > > On Fri, Apr 21, 2023, syzbot wrote: > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit: d3e1ee0e67e7 Add linux-next specific files for 20230421 > > > git tree: linux-next > > > console output: https://syzkaller.appspot.com/x/log.txt?x=16ac3de0280000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=53c789efbcc06cf6 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=094a74444165dbcd3a54 > > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > > > > > Unfortunately, I don't have any reproducer for this issue yet. > > > > > > Downloadable assets: > > > disk image: https://storage.googleapis.com/syzbot-assets/c558a9e1fe6a/disk-d3e1ee0e.raw.xz > > > vmlinux: https://storage.googleapis.com/syzbot-assets/2ec100a34c4c/vmlinux-d3e1ee0e.xz > > > kernel image: https://storage.googleapis.com/syzbot-assets/1afcd9936dc1/bzImage-d3e1ee0e.xz > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > Reported-by: syzbot+094a74444165dbcd3a54@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > > > ------------[ cut here ]------------ > > > WARNING: CPU: 0 PID: 12623 at arch/x86/kvm/mmu/tdp_mmu.c:943 kvm_tdp_mmu_invalidate_all_roots+0x2bd/0x370 arch/x86/kvm/mmu/tdp_mmu.c:943 > > > Modules linked in: > > > CPU: 0 PID: 12623 Comm: syz-executor.3 Not tainted 6.3.0-rc7-next-20230421-syzkaller #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 > > > RIP: 0010:kvm_tdp_mmu_invalidate_all_roots+0x2bd/0x370 arch/x86/kvm/mmu/tdp_mmu.c:943 > > > Call Trace: > > > <TASK> > > > kvm_mmu_uninit_tdp_mmu+0x16/0x100 arch/x86/kvm/mmu/tdp_mmu.c:48 > > > kvm_mmu_uninit_vm+0x6a/0x70 arch/x86/kvm/mmu/mmu.c:6239 > > > kvm_arch_destroy_vm+0x369/0x490 arch/x86/kvm/x86.c:12465 > > > kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1245 [inline] > > > kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:5017 [inline] > > > kvm_dev_ioctl+0x11be/0x1bb0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:5059 > > > vfs_ioctl fs/ioctl.c:51 [inline] > > > __do_sys_ioctl fs/ioctl.c:870 [inline] > > > __se_sys_ioctl fs/ioctl.c:856 [inline] > > > __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > > > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > > > Gah, kvm->users_count is elevated when the VM is destroyed if creation fails, > > but mmu_lock isn't held in that case, and lockdep yells. This particular bug is > > effectively a false positive, nothing else holds a reference to the VM. > > > > However, syzbot found another bug that _is_ a real problem (hasn't been reported > > upstream yet for whatever reason). > > It was staged in the moderation queue for manual moderation: > https://github.com/google/syzkaller/blob/master/docs/syzbot.md#moderation-queue > > here: > https://groups.google.com/g/syzkaller-upstream-moderation/c/pTGA87FeSIE > > I've pushed it upstream since you say it's worth fixing. Ah, thanks! For future reference, does "#syz upstream" also work from our internal bug tracker, or do I have to wait for the report to hit the moderation queue first?
