[ 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 '10.128.0.235' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 59.117715][ T7212] ================================================================== [ 59.117774][ T7212] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 59.117785][ T7212] Write of size 8 at addr ffff8880a722c108 by task syz-executor066/7212 [ 59.117789][ T7212] [ 59.117802][ T7212] CPU: 0 PID: 7212 Comm: syz-executor066 Not tainted 5.6.0-rc7-syzkaller #0 [ 59.117808][ T7212] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 59.117813][ T7212] Call Trace: [ 59.117830][ T7212] dump_stack+0x188/0x20d [ 59.117843][ T7212] ? con_shutdown+0x7f/0x90 [ 59.117863][ T7212] ? con_shutdown+0x7f/0x90 [ 59.117881][ T7212] print_address_description.constprop.0.cold+0xd3/0x315 [ 59.117892][ T7212] ? con_shutdown+0x7f/0x90 [ 59.117905][ T7212] ? con_shutdown+0x7f/0x90 [ 59.117917][ T7212] __kasan_report.cold+0x1a/0x32 [ 59.117934][ T7212] ? con_shutdown+0x7f/0x90 [ 59.117951][ T7212] kasan_report+0xe/0x20 [ 59.117963][ T7212] con_shutdown+0x7f/0x90 [ 59.117974][ T7212] ? update_region+0x140/0x140 [ 59.117990][ T7212] release_tty+0xca/0x450 [ 59.118006][ T7212] tty_release_struct+0x37/0x50 [ 59.118019][ T7212] tty_release+0xbc7/0xe90 [ 59.118046][ T7212] ? do_tty_hangup+0x30/0x30 [ 59.118057][ T7212] __fput+0x2da/0x850 [ 59.118086][ T7212] task_work_run+0x13f/0x1b0 [ 59.118110][ T7212] do_exit+0xb34/0x2dd0 [ 59.118141][ T7212] ? mm_update_next_owner+0x7a0/0x7a0 [ 59.118163][ T7212] ? up_read+0x1ab/0x750 [ 59.118177][ T7212] ? mark_held_locks+0x9f/0xe0 [ 59.118193][ T7212] ? down_read_non_owner+0x470/0x470 [ 59.118213][ T7212] ? handle_mm_fault+0x491/0xa10 [ 59.118232][ T7212] do_group_exit+0x125/0x340 [ 59.118249][ T7212] __x64_sys_exit_group+0x3a/0x50 [ 59.118264][ T7212] do_syscall_64+0xf6/0x7d0 [ 59.118283][ T7212] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 59.118293][ T7212] RIP: 0033:0x43ff38 [ 59.118305][ T7212] 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 [ 59.118312][ T7212] RSP: 002b:00007ffe596250b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 59.118324][ T7212] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 59.118331][ T7212] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 59.118339][ T7212] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 59.118347][ T7212] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 59.118354][ T7212] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 59.118383][ T7212] [ 59.118390][ T7212] Allocated by task 7212: [ 59.118401][ T7212] save_stack+0x1b/0x80 [ 59.118414][ T7212] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 59.118424][ T7212] kmem_cache_alloc_trace+0x153/0x7d0 [ 59.118434][ T7212] vc_allocate+0x1e2/0x6e0 [ 59.118444][ T7212] con_install+0x4f/0x400 [ 59.118454][ T7212] tty_init_dev+0xf5/0x460 [ 59.118463][ T7212] tty_open+0x47f/0xb30 [ 59.118473][ T7212] chrdev_open+0x219/0x5c0 [ 59.118485][ T7212] do_dentry_open+0x4a2/0x1250 [ 59.118495][ T7212] path_openat+0x122a/0x32b0 [ 59.118505][ T7212] do_filp_open+0x192/0x260 [ 59.118515][ T7212] do_sys_openat2+0x54c/0x740 [ 59.118525][ T7212] do_sys_open+0xc3/0x140 [ 59.118536][ T7212] do_syscall_64+0xf6/0x7d0 [ 59.118547][ T7212] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 59.118550][ T7212] [ 59.118556][ T7212] Freed by task 7219: [ 59.118567][ T7212] save_stack+0x1b/0x80 [ 59.118578][ T7212] __kasan_slab_free+0xf7/0x140 [ 59.118587][ T7212] kfree+0x109/0x2b0 [ 59.118598][ T7212] vt_disallocate_all+0x293/0x3b0 [ 59.118607][ T7212] vt_ioctl+0xb79/0x2470 [ 59.118616][ T7212] tty_ioctl+0xedd/0x1440 [ 59.118627][ T7212] ksys_ioctl+0x11a/0x180 [ 59.118638][ T7212] __x64_sys_ioctl+0x6f/0xb0 [ 59.118650][ T7212] do_syscall_64+0xf6/0x7d0 [ 59.118661][ T7212] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 59.118665][ T7212] [ 59.118674][ T7212] The buggy address belongs to the object at ffff8880a722c000 [ 59.118674][ T7212] which belongs to the cache kmalloc-2k of size 2048 [ 59.118684][ T7212] The buggy address is located 264 bytes inside of [ 59.118684][ T7212] 2048-byte region [ffff8880a722c000, ffff8880a722c800) [ 59.118688][ T7212] The buggy address belongs to the page: [ 59.118699][ T7212] page:ffffea00029c8b00 refcount:1 mapcount:0 mapping:ffff8880aa000e00 index:0x0 [ 59.118709][ T7212] flags: 0xfffe0000000200(slab) [ 59.118725][ T7212] raw: 00fffe0000000200 ffffea00029b7288 ffffea00029fb988 ffff8880aa000e00 [ 59.118737][ T7212] raw: 0000000000000000 ffff8880a722c000 0000000100000001 0000000000000000 [ 59.118742][ T7212] page dumped because: kasan: bad access detected [ 59.118745][ T7212] [ 59.118748][ T7212] Memory state around the buggy address: [ 59.118758][ T7212] ffff8880a722c000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.118767][ T7212] ffff8880a722c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.118777][ T7212] >ffff8880a722c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.118781][ T7212] ^ [ 59.118790][ T7212] ffff8880a722c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.118799][ T7212] ffff8880a722c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.118804][ T7212] ================================================================== [ 59.118808][ T7212] Disabling lock debugging due to kernel taint [ 59.120015][ T7212] Kernel panic - not syncing: panic_on_warn set ... [ 59.120030][ T7212] CPU: 0 PID: 7212 Comm: syz-executor066 Tainted: G B 5.6.0-rc7-syzkaller #0 [ 59.120036][ T7212] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 59.120039][ T7212] Call Trace: [ 59.120055][ T7212] dump_stack+0x188/0x20d [ 59.120071][ T7212] panic+0x2e3/0x75c [ 59.120083][ T7212] ? add_taint.cold+0x16/0x16 [ 59.120099][ T7212] ? preempt_schedule_common+0x5e/0xc0 [ 59.120111][ T7212] ? con_shutdown+0x7f/0x90 [ 59.120124][ T7212] ? ___preempt_schedule+0x16/0x18 [ 59.120137][ T7212] ? trace_hardirqs_on+0x55/0x220 [ 59.120155][ T7212] ? con_shutdown+0x7f/0x90 [ 59.120167][ T7212] end_report+0x43/0x49 [ 59.120177][ T7212] ? con_shutdown+0x7f/0x90 [ 59.120188][ T7212] __kasan_report.cold+0xd/0x32 [ 59.120201][ T7212] ? con_shutdown+0x7f/0x90 [ 59.120213][ T7212] kasan_report+0xe/0x20 [ 59.120222][ T7212] con_shutdown+0x7f/0x90 [ 59.120232][ T7212] ? update_region+0x140/0x140 [ 59.120242][ T7212] release_tty+0xca/0x450 [ 59.120254][ T7212] tty_release_struct+0x37/0x50 [ 59.120265][ T7212] tty_release+0xbc7/0xe90 [ 59.120283][ T7212] ? do_tty_hangup+0x30/0x30 [ 59.120292][ T7212] __fput+0x2da/0x850 [ 59.120308][ T7212] task_work_run+0x13f/0x1b0 [ 59.120323][ T7212] do_exit+0xb34/0x2dd0 [ 59.120341][ T7212] ? mm_update_next_owner+0x7a0/0x7a0 [ 59.120354][ T7212] ? up_read+0x1ab/0x750 [ 59.120365][ T7212] ? mark_held_locks+0x9f/0xe0 [ 59.120377][ T7212] ? down_read_non_owner+0x470/0x470 [ 59.120393][ T7212] ? handle_mm_fault+0x491/0xa10 [ 59.120407][ T7212] do_group_exit+0x125/0x340 [ 59.120420][ T7212] __x64_sys_exit_group+0x3a/0x50 [ 59.120432][ T7212] do_syscall_64+0xf6/0x7d0 [ 59.120447][ T7212] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 59.120455][ T7212] RIP: 0033:0x43ff38 [ 59.120466][ T7212] 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 [ 59.120471][ T7212] RSP: 002b:00007ffe596250b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 59.120482][ T7212] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 59.120489][ T7212] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 59.120495][ T7212] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 59.120502][ T7212] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 59.120507][ T7212] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 59.122200][ T7212] Kernel Offset: disabled [ 59.898937][ T7212] Rebooting in 86400 seconds..