[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.43' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 64.627270][ T7054] ================================================================== [ 64.627331][ T7054] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 64.627343][ T7054] Write of size 8 at addr ffff8880a9659108 by task syz-executor492/7054 [ 64.627346][ T7054] [ 64.627361][ T7054] CPU: 1 PID: 7054 Comm: syz-executor492 Not tainted 5.6.0-rc7-syzkaller #0 [ 64.627368][ T7054] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.627373][ T7054] Call Trace: [ 64.627390][ T7054] dump_stack+0x188/0x20d [ 64.627403][ T7054] ? con_shutdown+0x7f/0x90 [ 64.627416][ T7054] ? con_shutdown+0x7f/0x90 [ 64.627436][ T7054] print_address_description.constprop.0.cold+0xd3/0x315 [ 64.627447][ T7054] ? con_shutdown+0x7f/0x90 [ 64.627460][ T7054] ? con_shutdown+0x7f/0x90 [ 64.627473][ T7054] __kasan_report.cold+0x1a/0x32 [ 64.627491][ T7054] ? con_shutdown+0x7f/0x90 [ 64.627517][ T7054] kasan_report+0xe/0x20 [ 64.627530][ T7054] con_shutdown+0x7f/0x90 [ 64.627541][ T7054] ? update_region+0x140/0x140 [ 64.627552][ T7054] release_tty+0xca/0x450 [ 64.627569][ T7054] tty_release_struct+0x37/0x50 [ 64.627582][ T7054] tty_release+0xbc7/0xe90 [ 64.627614][ T7054] ? do_tty_hangup+0x30/0x30 [ 64.627625][ T7054] __fput+0x2da/0x850 [ 64.627653][ T7054] task_work_run+0x13f/0x1b0 [ 64.627679][ T7054] do_exit+0xb34/0x2dd0 [ 64.627711][ T7054] ? mm_update_next_owner+0x7a0/0x7a0 [ 64.627726][ T7054] ? up_read+0x1ab/0x750 [ 64.627740][ T7054] ? mark_held_locks+0x9f/0xe0 [ 64.627756][ T7054] ? down_read_non_owner+0x470/0x470 [ 64.627778][ T7054] ? handle_mm_fault+0x491/0xa10 [ 64.627798][ T7054] do_group_exit+0x125/0x340 [ 64.627816][ T7054] __x64_sys_exit_group+0x3a/0x50 [ 64.627832][ T7054] do_syscall_64+0xf6/0x7d0 [ 64.627852][ T7054] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.627863][ T7054] RIP: 0033:0x440018 [ 64.627877][ T7054] 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 [ 64.627884][ T7054] RSP: 002b:00007fff0fc79fe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 64.627896][ T7054] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440018 [ 64.627903][ T7054] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 64.627911][ T7054] RBP: 00000000004bfa70 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 64.627918][ T7054] R10: 000000000000000e R11: 0000000000000246 R12: 0000000000000001 [ 64.627925][ T7054] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 64.627955][ T7054] [ 64.627962][ T7054] Allocated by task 7054: [ 64.627973][ T7054] save_stack+0x1b/0x80 [ 64.627985][ T7054] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 64.627996][ T7054] kmem_cache_alloc_trace+0x153/0x7d0 [ 64.628006][ T7054] vc_allocate+0x1e2/0x6e0 [ 64.628016][ T7054] con_install+0x4f/0x400 [ 64.628026][ T7054] tty_init_dev+0xf5/0x460 [ 64.628035][ T7054] tty_open+0x47f/0xb30 [ 64.628046][ T7054] chrdev_open+0x219/0x5c0 [ 64.628058][ T7054] do_dentry_open+0x4a2/0x1250 [ 64.628068][ T7054] path_openat+0x122a/0x32b0 [ 64.628079][ T7054] do_filp_open+0x192/0x260 [ 64.628090][ T7054] do_sys_openat2+0x54c/0x740 [ 64.628101][ T7054] do_sys_open+0xc3/0x140 [ 64.628113][ T7054] do_syscall_64+0xf6/0x7d0 [ 64.628124][ T7054] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.628127][ T7054] [ 64.628133][ T7054] Freed by task 7057: [ 64.628144][ T7054] save_stack+0x1b/0x80 [ 64.628155][ T7054] __kasan_slab_free+0xf7/0x140 [ 64.628164][ T7054] kfree+0x109/0x2b0 [ 64.628176][ T7054] vt_disallocate_all+0x293/0x3b0 [ 64.628186][ T7054] vt_ioctl+0xb79/0x2470 [ 64.628196][ T7054] tty_ioctl+0xedd/0x1440 [ 64.628207][ T7054] ksys_ioctl+0x11a/0x180 [ 64.628219][ T7054] __x64_sys_ioctl+0x6f/0xb0 [ 64.628229][ T7054] do_syscall_64+0xf6/0x7d0 [ 64.628241][ T7054] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.628245][ T7054] [ 64.628254][ T7054] The buggy address belongs to the object at ffff8880a9659000 [ 64.628254][ T7054] which belongs to the cache kmalloc-2k of size 2048 [ 64.628264][ T7054] The buggy address is located 264 bytes inside of [ 64.628264][ T7054] 2048-byte region [ffff8880a9659000, ffff8880a9659800) [ 64.628268][ T7054] The buggy address belongs to the page: [ 64.628280][ T7054] page:ffffea0002a59640 refcount:1 mapcount:0 mapping:ffff8880aa000e00 index:0x0 [ 64.628289][ T7054] flags: 0xfffe0000000200(slab) [ 64.628305][ T7054] raw: 00fffe0000000200 ffffea0002994c08 ffffea00029946c8 ffff8880aa000e00 [ 64.628319][ T7054] raw: 0000000000000000 ffff8880a9659000 0000000100000001 0000000000000000 [ 64.628324][ T7054] page dumped because: kasan: bad access detected [ 64.628328][ T7054] [ 64.628332][ T7054] Memory state around the buggy address: [ 64.628342][ T7054] ffff8880a9659000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 64.628352][ T7054] ffff8880a9659080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 64.628361][ T7054] >ffff8880a9659100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 64.628365][ T7054] ^ [ 64.628374][ T7054] ffff8880a9659180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 64.628383][ T7054] ffff8880a9659200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 64.628387][ T7054] ================================================================== [ 64.628391][ T7054] Disabling lock debugging due to kernel taint [ 64.628436][ T7054] Kernel panic - not syncing: panic_on_warn set ... [ 64.628448][ T7054] CPU: 1 PID: 7054 Comm: syz-executor492 Tainted: G B 5.6.0-rc7-syzkaller #0 [ 64.628454][ T7054] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.628457][ T7054] Call Trace: [ 64.628469][ T7054] dump_stack+0x188/0x20d [ 64.628483][ T7054] panic+0x2e3/0x75c [ 64.628493][ T7054] ? add_taint.cold+0x16/0x16 [ 64.628514][ T7054] ? preempt_schedule_common+0x5e/0xc0 [ 64.628526][ T7054] ? con_shutdown+0x7f/0x90 [ 64.628538][ T7054] ? ___preempt_schedule+0x16/0x18 [ 64.628551][ T7054] ? trace_hardirqs_on+0x55/0x220 [ 64.628564][ T7054] ? con_shutdown+0x7f/0x90 [ 64.628575][ T7054] end_report+0x43/0x49 [ 64.628585][ T7054] ? con_shutdown+0x7f/0x90 [ 64.628596][ T7054] __kasan_report.cold+0xd/0x32 [ 64.628608][ T7054] ? con_shutdown+0x7f/0x90 [ 64.628621][ T7054] kasan_report+0xe/0x20 [ 64.628632][ T7054] con_shutdown+0x7f/0x90 [ 64.628641][ T7054] ? update_region+0x140/0x140 [ 64.628651][ T7054] release_tty+0xca/0x450 [ 64.628662][ T7054] tty_release_struct+0x37/0x50 [ 64.628673][ T7054] tty_release+0xbc7/0xe90 [ 64.628689][ T7054] ? do_tty_hangup+0x30/0x30 [ 64.628698][ T7054] __fput+0x2da/0x850 [ 64.628717][ T7054] task_work_run+0x13f/0x1b0 [ 64.628733][ T7054] do_exit+0xb34/0x2dd0 [ 64.628751][ T7054] ? mm_update_next_owner+0x7a0/0x7a0 [ 64.628763][ T7054] ? up_read+0x1ab/0x750 [ 64.628774][ T7054] ? mark_held_locks+0x9f/0xe0 [ 64.628787][ T7054] ? down_read_non_owner+0x470/0x470 [ 64.628802][ T7054] ? handle_mm_fault+0x491/0xa10 [ 64.628816][ T7054] do_group_exit+0x125/0x340 [ 64.628830][ T7054] __x64_sys_exit_group+0x3a/0x50 [ 64.628841][ T7054] do_syscall_64+0xf6/0x7d0 [ 64.628854][ T7054] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 64.628861][ T7054] RIP: 0033:0x440018 [ 64.628872][ T7054] 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 [ 64.628878][ T7054] RSP: 002b:00007fff0fc79fe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 64.628888][ T7054] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440018 [ 64.628894][ T7054] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 64.628900][ T7054] RBP: 00000000004bfa70 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 64.628906][ T7054] R10: 000000000000000e R11: 0000000000000246 R12: 0000000000000001 [ 64.628912][ T7054] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 64.630308][ T7054] Kernel Offset: disabled [ 65.407215][ T7054] Rebooting in 86400 seconds..