Starting System Logging Service... Starting getty on tty2-tty6 if dbus and logind are not available... [ OK ] Started Daily Cleanup of Temporary Directories. [ OK ] Reached target Timers. Starting Permit User Sessions... [ OK ] Started System Logging Service. [ OK ] Started Permit User Sessions. [ OK ] Found device /dev/ttyS0. [ 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 Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ OK ] Started Getty on tty2. [ 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 '10.128.15.203' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 66.699298][ T7030] ================================================================== [ 66.699361][ T7030] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 66.699373][ T7030] Write of size 8 at addr ffff8880a717f108 by task syz-executor202/7030 [ 66.699376][ T7030] [ 66.699389][ T7030] CPU: 1 PID: 7030 Comm: syz-executor202 Not tainted 5.6.0-rc7-syzkaller #0 [ 66.699396][ T7030] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.699400][ T7030] Call Trace: [ 66.699418][ T7030] dump_stack+0x188/0x20d [ 66.699431][ T7030] ? con_shutdown+0x7f/0x90 [ 66.699445][ T7030] ? con_shutdown+0x7f/0x90 [ 66.699464][ T7030] print_address_description.constprop.0.cold+0xd3/0x315 [ 66.699475][ T7030] ? con_shutdown+0x7f/0x90 [ 66.699488][ T7030] ? con_shutdown+0x7f/0x90 [ 66.699500][ T7030] __kasan_report.cold+0x1a/0x32 [ 66.699518][ T7030] ? con_shutdown+0x7f/0x90 [ 66.699543][ T7030] kasan_report+0xe/0x20 [ 66.699554][ T7030] con_shutdown+0x7f/0x90 [ 66.699565][ T7030] ? update_region+0x140/0x140 [ 66.699576][ T7030] release_tty+0xca/0x450 [ 66.699591][ T7030] tty_release_struct+0x37/0x50 [ 66.699604][ T7030] tty_release+0xbc7/0xe90 [ 66.699629][ T7030] ? do_tty_hangup+0x30/0x30 [ 66.699641][ T7030] __fput+0x2da/0x850 [ 66.699669][ T7030] task_work_run+0x13f/0x1b0 [ 66.699692][ T7030] do_exit+0xb34/0x2dd0 [ 66.699722][ T7030] ? mm_update_next_owner+0x7a0/0x7a0 [ 66.699744][ T7030] ? up_read+0x1ab/0x750 [ 66.699757][ T7030] ? mark_held_locks+0x9f/0xe0 [ 66.699773][ T7030] ? down_read_non_owner+0x470/0x470 [ 66.699794][ T7030] ? handle_mm_fault+0x491/0xa10 [ 66.699813][ T7030] do_group_exit+0x125/0x340 [ 66.699831][ T7030] __x64_sys_exit_group+0x3a/0x50 [ 66.699846][ T7030] do_syscall_64+0xf6/0x7d0 [ 66.699865][ T7030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.699876][ T7030] RIP: 0033:0x43ff38 [ 66.699889][ T7030] 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 [ 66.699895][ T7030] RSP: 002b:00007fff6fe504c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 66.699906][ T7030] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 66.699913][ T7030] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 66.699920][ T7030] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 66.699928][ T7030] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 66.699935][ T7030] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 66.699966][ T7030] [ 66.699972][ T7030] Allocated by task 7030: [ 66.699985][ T7030] save_stack+0x1b/0x80 [ 66.699996][ T7030] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 66.700006][ T7030] kmem_cache_alloc_trace+0x153/0x7d0 [ 66.700015][ T7030] vc_allocate+0x1e2/0x6e0 [ 66.700024][ T7030] con_install+0x4f/0x400 [ 66.700034][ T7030] tty_init_dev+0xf5/0x460 [ 66.700043][ T7030] tty_open+0x47f/0xb30 [ 66.700053][ T7030] chrdev_open+0x219/0x5c0 [ 66.700064][ T7030] do_dentry_open+0x4a2/0x1250 [ 66.700075][ T7030] path_openat+0x122a/0x32b0 [ 66.700085][ T7030] do_filp_open+0x192/0x260 [ 66.700094][ T7030] do_sys_openat2+0x54c/0x740 [ 66.700105][ T7030] do_sys_open+0xc3/0x140 [ 66.700116][ T7030] do_syscall_64+0xf6/0x7d0 [ 66.700126][ T7030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.700130][ T7030] [ 66.700135][ T7030] Freed by task 7032: [ 66.700145][ T7030] save_stack+0x1b/0x80 [ 66.700155][ T7030] __kasan_slab_free+0xf7/0x140 [ 66.700164][ T7030] kfree+0x109/0x2b0 [ 66.700176][ T7030] vt_disallocate_all+0x293/0x3b0 [ 66.700187][ T7030] vt_ioctl+0xb79/0x2470 [ 66.700197][ T7030] tty_ioctl+0xedd/0x1440 [ 66.700207][ T7030] ksys_ioctl+0x11a/0x180 [ 66.700218][ T7030] __x64_sys_ioctl+0x6f/0xb0 [ 66.700228][ T7030] do_syscall_64+0xf6/0x7d0 [ 66.700239][ T7030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.700243][ T7030] [ 66.700251][ T7030] The buggy address belongs to the object at ffff8880a717f000 [ 66.700251][ T7030] which belongs to the cache kmalloc-2k of size 2048 [ 66.700262][ T7030] The buggy address is located 264 bytes inside of [ 66.700262][ T7030] 2048-byte region [ffff8880a717f000, ffff8880a717f800) [ 66.700266][ T7030] The buggy address belongs to the page: [ 66.700276][ T7030] page:ffffea00029c5fc0 refcount:1 mapcount:0 mapping:ffff8880aa000e00 index:0x0 [ 66.700284][ T7030] flags: 0xfffe0000000200(slab) [ 66.700299][ T7030] raw: 00fffe0000000200 ffffea00027e3608 ffffea0002a2f908 ffff8880aa000e00 [ 66.700313][ T7030] raw: 0000000000000000 ffff8880a717f000 0000000100000001 0000000000000000 [ 66.700318][ T7030] page dumped because: kasan: bad access detected [ 66.700321][ T7030] [ 66.700325][ T7030] Memory state around the buggy address: [ 66.700334][ T7030] ffff8880a717f000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.700343][ T7030] ffff8880a717f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.700352][ T7030] >ffff8880a717f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.700356][ T7030] ^ [ 66.700365][ T7030] ffff8880a717f180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.700374][ T7030] ffff8880a717f200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.700378][ T7030] ================================================================== [ 66.700382][ T7030] Disabling lock debugging due to kernel taint [ 66.700413][ T7030] Kernel panic - not syncing: panic_on_warn set ... [ 66.700426][ T7030] CPU: 1 PID: 7030 Comm: syz-executor202 Tainted: G B 5.6.0-rc7-syzkaller #0 [ 66.700431][ T7030] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.700434][ T7030] Call Trace: [ 66.700449][ T7030] dump_stack+0x188/0x20d [ 66.700464][ T7030] panic+0x2e3/0x75c [ 66.700476][ T7030] ? add_taint.cold+0x16/0x16 [ 66.700486][ T7030] ? retint_kernel+0x2b/0x2b [ 66.700505][ T7030] ? trace_hardirqs_on+0x55/0x220 [ 66.700519][ T7030] ? con_shutdown+0x7f/0x90 [ 66.700532][ T7030] end_report+0x43/0x49 [ 66.700542][ T7030] ? con_shutdown+0x7f/0x90 [ 66.700552][ T7030] __kasan_report.cold+0xd/0x32 [ 66.700564][ T7030] ? con_shutdown+0x7f/0x90 [ 66.700577][ T7030] kasan_report+0xe/0x20 [ 66.700588][ T7030] con_shutdown+0x7f/0x90 [ 66.700597][ T7030] ? update_region+0x140/0x140 [ 66.700607][ T7030] release_tty+0xca/0x450 [ 66.700619][ T7030] tty_release_struct+0x37/0x50 [ 66.700630][ T7030] tty_release+0xbc7/0xe90 [ 66.700648][ T7030] ? do_tty_hangup+0x30/0x30 [ 66.700657][ T7030] __fput+0x2da/0x850 [ 66.700674][ T7030] task_work_run+0x13f/0x1b0 [ 66.700690][ T7030] do_exit+0xb34/0x2dd0 [ 66.700711][ T7030] ? mm_update_next_owner+0x7a0/0x7a0 [ 66.700724][ T7030] ? up_read+0x1ab/0x750 [ 66.700742][ T7030] ? mark_held_locks+0x9f/0xe0 [ 66.700755][ T7030] ? down_read_non_owner+0x470/0x470 [ 66.700769][ T7030] ? handle_mm_fault+0x491/0xa10 [ 66.700782][ T7030] do_group_exit+0x125/0x340 [ 66.700794][ T7030] __x64_sys_exit_group+0x3a/0x50 [ 66.700808][ T7030] do_syscall_64+0xf6/0x7d0 [ 66.700822][ T7030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.700830][ T7030] RIP: 0033:0x43ff38 [ 66.700840][ T7030] 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 [ 66.700845][ T7030] RSP: 002b:00007fff6fe504c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 66.700855][ T7030] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 66.700862][ T7030] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 66.700868][ T7030] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 66.700874][ T7030] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 66.700880][ T7030] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 66.702038][ T7030] Kernel Offset: disabled