[ OK ] Reached target Basic System. Starting getty on tty2-tty6 if dbus and logind are not available... Starting Permit User Sessions... Starting OpenBSD Secure Shell server... Starting System Logging Service... [ OK ] Started Regular background program processing daemon. [ OK ] Started Permit User Sessions. [ OK ] Started System Logging Service. [ OK ] Started OpenBSD Secure Shell server. [ OK ] Started getty on tty2-tty6 if dbus and logind are not available. [ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Started Getty on tty6. [ OK ] Started Getty on tty5. [ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.64' (ECDSA) to the list of known hosts. executing program executing program executing program executing program syzkaller login: [ 67.983618][ T7026] ================================================================== [ 67.983678][ T7026] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 67.983689][ T7026] Write of size 8 at addr ffff888094f31108 by task syz-executor178/7026 [ 67.983693][ T7026] [ 67.983707][ T7026] CPU: 0 PID: 7026 Comm: syz-executor178 Not tainted 5.6.0-rc7-syzkaller #0 [ 67.983714][ T7026] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.983719][ T7026] Call Trace: [ 67.983737][ T7026] dump_stack+0x188/0x20d [ 67.983750][ T7026] ? con_shutdown+0x7f/0x90 [ 67.983764][ T7026] ? con_shutdown+0x7f/0x90 [ 67.983784][ T7026] print_address_description.constprop.0.cold+0xd3/0x315 [ 67.983796][ T7026] ? con_shutdown+0x7f/0x90 [ 67.983809][ T7026] ? con_shutdown+0x7f/0x90 [ 67.983822][ T7026] __kasan_report.cold+0x1a/0x32 [ 67.983839][ T7026] ? con_shutdown+0x7f/0x90 [ 67.983857][ T7026] kasan_report+0xe/0x20 [ 67.983869][ T7026] con_shutdown+0x7f/0x90 [ 67.983890][ T7026] ? update_region+0x140/0x140 [ 67.983902][ T7026] release_tty+0xca/0x450 [ 67.983919][ T7026] tty_release_struct+0x37/0x50 [ 67.983933][ T7026] tty_release+0xbc7/0xe90 [ 67.983961][ T7026] ? do_tty_hangup+0x30/0x30 [ 67.983973][ T7026] __fput+0x2da/0x850 [ 67.984003][ T7026] task_work_run+0x13f/0x1b0 [ 67.984028][ T7026] do_exit+0xb34/0x2dd0 [ 67.984060][ T7026] ? mm_update_next_owner+0x7a0/0x7a0 [ 67.984076][ T7026] ? up_read+0x1ab/0x750 [ 67.984125][ T7026] ? mark_held_locks+0x9f/0xe0 [ 67.984143][ T7026] ? down_read_non_owner+0x470/0x470 [ 67.984165][ T7026] ? handle_mm_fault+0x491/0xa10 [ 67.984186][ T7026] do_group_exit+0x125/0x340 [ 67.984205][ T7026] __x64_sys_exit_group+0x3a/0x50 [ 67.984221][ T7026] do_syscall_64+0xf6/0x7d0 [ 67.984241][ T7026] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.984252][ T7026] RIP: 0033:0x43ff58 [ 67.984264][ T7026] Code: Bad RIP value. [ 67.984271][ T7026] RSP: 002b:00007ffedbf23fd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 67.984284][ T7026] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff58 [ 67.984292][ T7026] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 67.984300][ T7026] RBP: 00000000004bf970 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 67.984309][ T7026] R10: 000000000000000e R11: 0000000000000246 R12: 0000000000000001 [ 67.984316][ T7026] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 67.984349][ T7026] [ 67.984356][ T7026] Allocated by task 7026: [ 67.984368][ T7026] save_stack+0x1b/0x80 [ 67.984379][ T7026] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 67.984390][ T7026] kmem_cache_alloc_trace+0x153/0x7d0 [ 67.984401][ T7026] vc_allocate+0x1e2/0x6e0 [ 67.984412][ T7026] con_install+0x4f/0x400 [ 67.984422][ T7026] tty_init_dev+0xf5/0x460 [ 67.984432][ T7026] tty_open+0x47f/0xb30 [ 67.984444][ T7026] chrdev_open+0x219/0x5c0 [ 67.984455][ T7026] do_dentry_open+0x4a2/0x1250 [ 67.984467][ T7026] path_openat+0x122a/0x32b0 [ 67.984478][ T7026] do_filp_open+0x192/0x260 [ 67.984489][ T7026] do_sys_openat2+0x54c/0x740 [ 67.984500][ T7026] do_sys_open+0xc3/0x140 [ 67.984512][ T7026] do_syscall_64+0xf6/0x7d0 [ 67.984523][ T7026] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.984527][ T7026] [ 67.984533][ T7026] Freed by task 7028: [ 67.984544][ T7026] save_stack+0x1b/0x80 [ 67.984556][ T7026] __kasan_slab_free+0xf7/0x140 [ 67.984566][ T7026] kfree+0x109/0x2b0 [ 67.984578][ T7026] vt_disallocate_all+0x293/0x3b0 [ 67.984589][ T7026] vt_ioctl+0xb79/0x2470 [ 67.984599][ T7026] tty_ioctl+0xedd/0x1440 [ 67.984611][ T7026] ksys_ioctl+0x11a/0x180 [ 67.984623][ T7026] __x64_sys_ioctl+0x6f/0xb0 [ 67.984635][ T7026] do_syscall_64+0xf6/0x7d0 [ 67.984646][ T7026] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.984650][ T7026] [ 67.984659][ T7026] The buggy address belongs to the object at ffff888094f31000 [ 67.984659][ T7026] which belongs to the cache kmalloc-2k of size 2048 [ 67.984671][ T7026] The buggy address is located 264 bytes inside of [ 67.984671][ T7026] 2048-byte region [ffff888094f31000, ffff888094f31800) [ 67.984675][ T7026] The buggy address belongs to the page: [ 67.984687][ T7026] page:ffffea000253cc40 refcount:1 mapcount:0 mapping:ffff8880aa000e00 index:0x0 [ 67.984697][ T7026] flags: 0xfffe0000000200(slab) [ 67.984715][ T7026] raw: 00fffe0000000200 ffffea000252b788 ffffea0002a3c2c8 ffff8880aa000e00 [ 67.984730][ T7026] raw: 0000000000000000 ffff888094f31000 0000000100000001 0000000000000000 [ 67.984736][ T7026] page dumped because: kasan: bad access detected [ 67.984740][ T7026] [ 67.984744][ T7026] Memory state around the buggy address: [ 67.984755][ T7026] ffff888094f31000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 67.984765][ T7026] ffff888094f31080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 67.984775][ T7026] >ffff888094f31100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 67.984780][ T7026] ^ [ 67.984790][ T7026] ffff888094f31180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 67.984800][ T7026] ffff888094f31200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 67.984804][ T7026] ================================================================== [ 67.984809][ T7026] Disabling lock debugging due to kernel taint [ 67.985149][ T7026] Kernel panic - not syncing: panic_on_warn set ... [ 67.985162][ T7026] CPU: 0 PID: 7026 Comm: syz-executor178 Tainted: G B 5.6.0-rc7-syzkaller #0 [ 67.985168][ T7026] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.985171][ T7026] Call Trace: [ 67.985186][ T7026] dump_stack+0x188/0x20d [ 67.985202][ T7026] panic+0x2e3/0x75c [ 67.985214][ T7026] ? add_taint.cold+0x16/0x16 [ 67.985230][ T7026] ? preempt_schedule_common+0x5e/0xc0 [ 67.985242][ T7026] ? con_shutdown+0x7f/0x90 [ 67.985255][ T7026] ? ___preempt_schedule+0x16/0x18 [ 67.985270][ T7026] ? trace_hardirqs_on+0x55/0x220 [ 67.985283][ T7026] ? con_shutdown+0x7f/0x90 [ 67.985296][ T7026] end_report+0x43/0x49 [ 67.985307][ T7026] ? con_shutdown+0x7f/0x90 [ 67.985318][ T7026] __kasan_report.cold+0xd/0x32 [ 67.985332][ T7026] ? con_shutdown+0x7f/0x90 [ 67.985346][ T7026] kasan_report+0xe/0x20 [ 67.985357][ T7026] con_shutdown+0x7f/0x90 [ 67.985368][ T7026] ? update_region+0x140/0x140 [ 67.985377][ T7026] release_tty+0xca/0x450 [ 67.985389][ T7026] tty_release_struct+0x37/0x50 [ 67.985401][ T7026] tty_release+0xbc7/0xe90 [ 67.985420][ T7026] ? do_tty_hangup+0x30/0x30 [ 67.985430][ T7026] __fput+0x2da/0x850 [ 67.985450][ T7026] task_work_run+0x13f/0x1b0 [ 67.985466][ T7026] do_exit+0xb34/0x2dd0 [ 67.985488][ T7026] ? mm_update_next_owner+0x7a0/0x7a0 [ 67.985500][ T7026] ? up_read+0x1ab/0x750 [ 67.985512][ T7026] ? mark_held_locks+0x9f/0xe0 [ 67.985526][ T7026] ? down_read_non_owner+0x470/0x470 [ 67.985542][ T7026] ? handle_mm_fault+0x491/0xa10 [ 67.985557][ T7026] do_group_exit+0x125/0x340 [ 67.985571][ T7026] __x64_sys_exit_group+0x3a/0x50 [ 67.985584][ T7026] do_syscall_64+0xf6/0x7d0 [ 67.985599][ T7026] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.985608][ T7026] RIP: 0033:0x43ff58 [ 67.985620][ T7026] Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 [ 67.985627][ T7026] RSP: 002b:00007ffedbf23fd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 67.985638][ T7026] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff58 [ 67.985645][ T7026] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 67.985652][ T7026] RBP: 00000000004bf970 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 67.985658][ T7026] R10: 000000000000000e R11: 0000000000000246 R12: 0000000000000001 [ 67.985664][ T7026] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 67.986675][ T7026] Kernel Offset: disabled [ 68.734335][ T7026] Rebooting in 86400 seconds..