* [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots @ 2023-04-21 19:16 syzbot 2023-04-21 21:52 ` Sean Christopherson 2023-04-21 22:02 ` Sean Christopherson 0 siblings, 2 replies; 5+ messages in thread From: syzbot @ 2023-04-21 19:16 UTC (permalink / raw) To: bp, dave.hansen, hpa, kvm, linux-kernel, mingo, pbonzini, seanjc, syzkaller-bugs, tglx, x86 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@syzkaller.appspotmail.com ------------[ 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 Code: 00 e8 a7 67 64 00 49 8d 7c 24 18 31 f6 e8 eb 23 ec 08 31 ff 89 c3 89 c6 e8 b0 63 64 00 85 db 0f 85 00 fe ff ff e8 83 67 64 00 <0f> 0b e9 f4 fd ff ff 48 89 ef e8 94 46 b7 00 e9 88 fd ff ff e8 4a RSP: 0018:ffffc90005f7fc80 EFLAGS: 00010212 RAX: 0000000000015eaf RBX: 0000000000000000 RCX: ffffc9000e5cd000 RDX: 0000000000040000 RSI: ffffffff811f7dcd RDI: 0000000000000005 RBP: ffffc900062ba788 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc900062b1000 R13: 0000000000000000 R14: 0000000000000006 R15: ffffc900062b19d8 FS: 00007f9c99c7c700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa626bad988 CR3: 000000001cd68000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 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 RIP: 0033:0x7f9c98e8c169 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9c99c7c168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9c98fac120 RCX: 00007f9c98e8c169 RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000005 RBP: 00007f9c98ee7ca1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff0f7a772f R14: 00007f9c99c7c300 R15: 0000000000022000 </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@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots 2023-04-21 19:16 [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots syzbot @ 2023-04-21 21:52 ` Sean Christopherson 2023-04-24 7:01 ` Dmitry Vyukov 2023-04-21 22:02 ` Sean Christopherson 1 sibling, 1 reply; 5+ messages in thread From: Sean Christopherson @ 2023-04-21 21:52 UTC (permalink / raw) To: syzbot Cc: bp, dave.hansen, hpa, kvm, linux-kernel, mingo, pbonzini, syzkaller-bugs, tglx, x86 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@syzkaller.appspotmail.com > > ------------[ 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). Not holding mmu_lock during "real" VM destruction is problematic because walking the list can race with the asynchronous worker deleting and freeing from the list. Posted a fixed version[*] that should resolve both issues by protecting the walk with RCU. [*] https://lore.kernel.org/all/20230421214946.2571580-1-seanjc@google.com ================================================================== BUG: KASAN: slab-use-after-free in kvm_tdp_mmu_invalidate_all_roots+0x2e3/0x370 arch/x86/kvm/mmu/tdp_mmu.c:945 Read of size 8 at addr ffff88801c8cf948 by task syz-executor.1/17012 CPU: 0 PID: 17012 Comm: syz-executor.1 Not tainted 6.3.0-rc7-next-20230421-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351 print_report mm/kasan/report.c:462 [inline] kasan_report+0x11c/0x130 mm/kasan/report.c:572 kvm_tdp_mmu_invalidate_all_roots+0x2e3/0x370 arch/x86/kvm/mmu/tdp_mmu.c:945 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_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1313 [inline] kvm_put_kvm+0x4da/0xae0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1347 kvm_vcpu_release+0x51/0x70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3846 __fput+0x27c/0xa90 fs/file_table.c:321 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd7a583e01b Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:00007ffc821a2fb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 000000000000000a RCX: 00007fd7a583e01b RDX: 0000000000000000 RSI: 00007fd7a5400000 RDI: 0000000000000009 RBP: 00007fd7a59ad980 R08: 0000000000000000 R09: 0000000071612a4e R10: 0000000000000000 R11: 0000000000000293 R12: 000000000014ffb4 R13: 00007ffc821a30b0 R14: 00007fd7a59ac050 R15: 0000000000000032 </TASK> ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots 2023-04-21 21:52 ` Sean Christopherson @ 2023-04-24 7:01 ` Dmitry Vyukov 2023-04-24 15:36 ` Sean Christopherson 0 siblings, 1 reply; 5+ messages in thread From: Dmitry Vyukov @ 2023-04-24 7:01 UTC (permalink / raw) To: Sean Christopherson Cc: syzbot, bp, dave.hansen, hpa, kvm, linux-kernel, mingo, pbonzini, syzkaller-bugs, tglx, x86 On Fri, 21 Apr 2023 at 23:52, 'Sean Christopherson' via syzkaller-bugs <syzkaller-bugs@googlegroups.com> 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@syzkaller.appspotmail.com > > > > ------------[ 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. > Not holding mmu_lock during "real" VM destruction > is problematic because walking the list can race with the asynchronous worker > deleting and freeing from the list. > > Posted a fixed version[*] that should resolve both issues by protecting the walk > with RCU. > > [*] https://lore.kernel.org/all/20230421214946.2571580-1-seanjc@google.com > > ================================================================== > BUG: KASAN: slab-use-after-free in kvm_tdp_mmu_invalidate_all_roots+0x2e3/0x370 arch/x86/kvm/mmu/tdp_mmu.c:945 > Read of size 8 at addr ffff88801c8cf948 by task syz-executor.1/17012 > > CPU: 0 PID: 17012 Comm: syz-executor.1 Not tainted 6.3.0-rc7-next-20230421-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 > print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351 > print_report mm/kasan/report.c:462 [inline] > kasan_report+0x11c/0x130 mm/kasan/report.c:572 > kvm_tdp_mmu_invalidate_all_roots+0x2e3/0x370 arch/x86/kvm/mmu/tdp_mmu.c:945 > 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_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1313 [inline] > kvm_put_kvm+0x4da/0xae0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1347 > kvm_vcpu_release+0x51/0x70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3846 > __fput+0x27c/0xa90 fs/file_table.c:321 > task_work_run+0x16f/0x270 kernel/task_work.c:179 > resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] > exit_to_user_mode_loop kernel/entry/common.c:171 [inline] > exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204 > __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] > syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 > do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7fd7a583e01b > Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 > RSP: 002b:00007ffc821a2fb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 > RAX: 0000000000000000 RBX: 000000000000000a RCX: 00007fd7a583e01b > RDX: 0000000000000000 RSI: 00007fd7a5400000 RDI: 0000000000000009 > RBP: 00007fd7a59ad980 R08: 0000000000000000 R09: 0000000071612a4e > R10: 0000000000000000 R11: 0000000000000293 R12: 000000000014ffb4 > R13: 00007ffc821a30b0 R14: 00007fd7a59ac050 R15: 0000000000000032 > </TASK> > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/ZEMFpqxvOHd2kZiu%40google.com. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots 2023-04-24 7:01 ` Dmitry Vyukov @ 2023-04-24 15:36 ` Sean Christopherson 0 siblings, 0 replies; 5+ messages in thread From: Sean Christopherson @ 2023-04-24 15:36 UTC (permalink / raw) To: Dmitry Vyukov Cc: syzbot, bp, dave.hansen, hpa, kvm, linux-kernel, mingo, pbonzini, syzkaller-bugs, tglx, x86 On Mon, Apr 24, 2023, Dmitry Vyukov wrote: > On Fri, 21 Apr 2023 at 23:52, 'Sean Christopherson' via syzkaller-bugs > <syzkaller-bugs@googlegroups.com> 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@syzkaller.appspotmail.com > > > > > > ------------[ 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? ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots 2023-04-21 19:16 [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots syzbot 2023-04-21 21:52 ` Sean Christopherson @ 2023-04-21 22:02 ` Sean Christopherson 1 sibling, 0 replies; 5+ messages in thread From: Sean Christopherson @ 2023-04-21 22:02 UTC (permalink / raw) To: syzbot Cc: bp, dave.hansen, hpa, kvm, linux-kernel, mingo, pbonzini, syzkaller-bugs, tglx, x86 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@syzkaller.appspotmail.com Time to see if syzbot gets confused by a fix that was squashed into the guilty commit. #syz fix: KVM: x86: Preserve TDP MMU roots until they are explicitly invalidated ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-04-24 15:36 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2023-04-21 19:16 [syzbot] [kvm?] WARNING in kvm_tdp_mmu_invalidate_all_roots syzbot 2023-04-21 21:52 ` Sean Christopherson 2023-04-24 7:01 ` Dmitry Vyukov 2023-04-24 15:36 ` Sean Christopherson 2023-04-21 22:02 ` Sean Christopherson
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