[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 60.148679][ T27] audit: type=1800 audit(1575919594.103:25): pid=8939 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 60.182895][ T27] audit: type=1800 audit(1575919594.113:26): pid=8939 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 60.208753][ T27] audit: type=1800 audit(1575919594.113:27): pid=8939 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.15.230' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 70.767721][ T9100] ================================================================== [ 70.775982][ T9100] BUG: KASAN: use-after-free in try_to_grab_pending+0x115/0x910 [ 70.783617][ T9100] Write of size 8 at addr ffff8880a79f7008 by task syz-executor196/9100 [ 70.791935][ T9100] [ 70.794263][ T9100] CPU: 1 PID: 9100 Comm: syz-executor196 Not tainted 5.5.0-rc1-syzkaller #0 [ 70.802945][ T9100] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 70.813085][ T9100] Call Trace: [ 70.816386][ T9100] dump_stack+0x197/0x210 [ 70.820729][ T9100] ? try_to_grab_pending+0x115/0x910 [ 70.826030][ T9100] print_address_description.constprop.0.cold+0xd4/0x30b [ 70.833082][ T9100] ? try_to_grab_pending+0x115/0x910 [ 70.838388][ T9100] ? try_to_grab_pending+0x115/0x910 [ 70.843698][ T9100] __kasan_report.cold+0x1b/0x41 [ 70.848652][ T9100] ? try_to_grab_pending+0x115/0x910 [ 70.853955][ T9100] kasan_report+0x12/0x20 [ 70.858308][ T9100] check_memory_region+0x134/0x1a0 [ 70.863440][ T9100] __kasan_check_write+0x14/0x20 [ 70.868392][ T9100] try_to_grab_pending+0x115/0x910 [ 70.873531][ T9100] ? __kasan_check_read+0x11/0x20 [ 70.878573][ T9100] __cancel_work_timer+0xc4/0x540 [ 70.883623][ T9100] ? mod_delayed_work_on+0x200/0x200 [ 70.888938][ T9100] ? get_work_pool+0x1b0/0x1b0 [ 70.893721][ T9100] cancel_work_sync+0x18/0x20 [ 70.898413][ T9100] tty_buffer_cancel_work+0x16/0x20 [ 70.903626][ T9100] release_tty+0x261/0x470 [ 70.908254][ T9100] tty_release_struct+0x3c/0x50 [ 70.913096][ T9100] tty_release+0xbcb/0xe90 [ 70.917556][ T9100] __fput+0x2ff/0x890 [ 70.921520][ T9100] ? do_tty_hangup+0x30/0x30 [ 70.926126][ T9100] ____fput+0x16/0x20 [ 70.930093][ T9100] task_work_run+0x145/0x1c0 [ 70.934666][ T9100] do_exit+0x8e7/0x2ef0 [ 70.938808][ T9100] ? mm_update_next_owner+0x7c0/0x7c0 [ 70.944169][ T9100] ? down_read_non_owner+0x490/0x490 [ 70.949433][ T9100] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 70.955660][ T9100] ? handle_mm_fault+0x4ab/0xa50 [ 70.960589][ T9100] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 70.966032][ T9100] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 70.971470][ T9100] do_group_exit+0x135/0x360 [ 70.976042][ T9100] __x64_sys_exit_group+0x44/0x50 [ 70.981061][ T9100] do_syscall_64+0xfa/0x790 [ 70.985566][ T9100] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.991488][ T9100] RIP: 0033:0x43ffc8 [ 70.995379][ T9100] Code: Bad RIP value. [ 70.999717][ T9100] RSP: 002b:00007ffd8b6ca3e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 71.008123][ T9100] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ffc8 [ 71.016077][ T9100] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 71.024029][ T9100] RBP: 00000000004bf9d0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 71.032067][ T9100] R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001 [ 71.040017][ T9100] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 71.047978][ T9100] [ 71.050285][ T9100] Allocated by task 9100: [ 71.054605][ T9100] save_stack+0x23/0x90 [ 71.058743][ T9100] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 71.064502][ T9100] kasan_kmalloc+0x9/0x10 [ 71.068818][ T9100] kmem_cache_alloc_trace+0x158/0x790 [ 71.074170][ T9100] vc_allocate+0x1fc/0x760 [ 71.078563][ T9100] con_install+0x52/0x410 [ 71.082871][ T9100] tty_init_dev+0xf9/0x470 [ 71.087273][ T9100] tty_open+0x4a5/0xbb0 [ 71.091411][ T9100] chrdev_open+0x245/0x6b0 [ 71.095810][ T9100] do_dentry_open+0x4e6/0x1380 [ 71.100551][ T9100] vfs_open+0xa0/0xd0 [ 71.104515][ T9100] path_openat+0x10df/0x4500 [ 71.109081][ T9100] do_filp_open+0x1a1/0x280 [ 71.113571][ T9100] do_sys_open+0x3fe/0x5d0 [ 71.117967][ T9100] __x64_sys_open+0x7e/0xc0 [ 71.122468][ T9100] do_syscall_64+0xfa/0x790 [ 71.127029][ T9100] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 71.132910][ T9100] [ 71.135225][ T9100] Freed by task 9102: [ 71.139208][ T9100] save_stack+0x23/0x90 [ 71.143400][ T9100] __kasan_slab_free+0x102/0x150 [ 71.148327][ T9100] kasan_slab_free+0xe/0x10 [ 71.152822][ T9100] kfree+0x10a/0x2c0 [ 71.156819][ T9100] vt_disallocate_all+0x2bd/0x3e0 [ 71.161870][ T9100] vt_ioctl+0xc38/0x26d0 [ 71.166096][ T9100] tty_ioctl+0xa37/0x14f0 [ 71.170470][ T9100] do_vfs_ioctl+0x977/0x14e0 [ 71.175331][ T9100] ksys_ioctl+0xab/0xd0 [ 71.179591][ T9100] __x64_sys_ioctl+0x73/0xb0 [ 71.184178][ T9100] do_syscall_64+0xfa/0x790 [ 71.188680][ T9100] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 71.194544][ T9100] [ 71.196853][ T9100] The buggy address belongs to the object at ffff8880a79f7000 [ 71.196853][ T9100] which belongs to the cache kmalloc-2k of size 2048 [ 71.210904][ T9100] The buggy address is located 8 bytes inside of [ 71.210904][ T9100] 2048-byte region [ffff8880a79f7000, ffff8880a79f7800) [ 71.224065][ T9100] The buggy address belongs to the page: [ 71.229678][ T9100] page:ffffea00029e7dc0 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 [ 71.238770][ T9100] raw: 00fffe0000000200 ffffea0002a3c9c8 ffffea00029c2788 ffff8880aa400e00 [ 71.247333][ T9100] raw: 0000000000000000 ffff8880a79f7000 0000000100000001 0000000000000000 [ 71.255904][ T9100] page dumped because: kasan: bad access detected [ 71.262288][ T9100] [ 71.264595][ T9100] Memory state around the buggy address: [ 71.270203][ T9100] ffff8880a79f6f00: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc [ 71.278239][ T9100] ffff8880a79f6f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 71.286277][ T9100] >ffff8880a79f7000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 71.294314][ T9100] ^ [ 71.298633][ T9100] ffff8880a79f7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 71.306671][ T9100] ffff8880a79f7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 71.314705][ T9100] ================================================================== [ 71.322762][ T9100] Disabling lock debugging due to kernel taint [ 71.328901][ T9100] Kernel panic - not syncing: panic_on_warn set ... [ 71.335469][ T9100] CPU: 1 PID: 9100 Comm: syz-executor196 Tainted: G B 5.5.0-rc1-syzkaller #0 [ 71.345502][ T9100] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 71.355543][ T9100] Call Trace: [ 71.358827][ T9100] dump_stack+0x197/0x210 [ 71.363140][ T9100] panic+0x2e3/0x75c [ 71.367009][ T9100] ? add_taint.cold+0x16/0x16 [ 71.371700][ T9100] ? try_to_grab_pending+0x115/0x910 [ 71.376977][ T9100] ? trace_hardirqs_off+0x62/0x240 [ 71.382253][ T9100] ? trace_hardirqs_off+0x59/0x240 [ 71.387462][ T9100] ? try_to_grab_pending+0x115/0x910 [ 71.392742][ T9100] end_report+0x47/0x4f [ 71.396922][ T9100] ? try_to_grab_pending+0x115/0x910 [ 71.402182][ T9100] __kasan_report.cold+0xe/0x41 [ 71.407009][ T9100] ? try_to_grab_pending+0x115/0x910 [ 71.412269][ T9100] kasan_report+0x12/0x20 [ 71.416581][ T9100] check_memory_region+0x134/0x1a0 [ 71.421721][ T9100] __kasan_check_write+0x14/0x20 [ 71.426678][ T9100] try_to_grab_pending+0x115/0x910 [ 71.431780][ T9100] ? __kasan_check_read+0x11/0x20 [ 71.436783][ T9100] __cancel_work_timer+0xc4/0x540 [ 71.441793][ T9100] ? mod_delayed_work_on+0x200/0x200 [ 71.447061][ T9100] ? get_work_pool+0x1b0/0x1b0 [ 71.451856][ T9100] cancel_work_sync+0x18/0x20 [ 71.457415][ T9100] tty_buffer_cancel_work+0x16/0x20 [ 71.462594][ T9100] release_tty+0x261/0x470 [ 71.467103][ T9100] tty_release_struct+0x3c/0x50 [ 71.471951][ T9100] tty_release+0xbcb/0xe90 [ 71.476355][ T9100] __fput+0x2ff/0x890 [ 71.480314][ T9100] ? do_tty_hangup+0x30/0x30 [ 71.484916][ T9100] ____fput+0x16/0x20 [ 71.488921][ T9100] task_work_run+0x145/0x1c0 [ 71.493488][ T9100] do_exit+0x8e7/0x2ef0 [ 71.497621][ T9100] ? mm_update_next_owner+0x7c0/0x7c0 [ 71.503023][ T9100] ? down_read_non_owner+0x490/0x490 [ 71.508306][ T9100] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 71.514520][ T9100] ? handle_mm_fault+0x4ab/0xa50 [ 71.519474][ T9100] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 71.524907][ T9100] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 71.530366][ T9100] do_group_exit+0x135/0x360 [ 71.534937][ T9100] __x64_sys_exit_group+0x44/0x50 [ 71.540117][ T9100] do_syscall_64+0xfa/0x790 [ 71.544691][ T9100] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 71.550567][ T9100] RIP: 0033:0x43ffc8 [ 71.554453][ T9100] Code: Bad RIP value. [ 71.558492][ T9100] RSP: 002b:00007ffd8b6ca3e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 71.566885][ T9100] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ffc8 [ 71.574919][ T9100] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 71.582865][ T9100] RBP: 00000000004bf9d0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 71.590809][ T9100] R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001 [ 71.598754][ T9100] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 71.608286][ T9100] Kernel Offset: disabled [ 71.612609][ T9100] Rebooting in 86400 seconds..