[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.337760][ T27] audit: type=1800 audit(1581593025.648:25): pid=8649 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.356849][ T27] audit: type=1800 audit(1581593025.648:26): pid=8649 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.384934][ T27] audit: type=1800 audit(1581593025.648:27): pid=8649 uid=0 auid=4294967295 ses=4294967295 subj=_ 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 '10.128.15.213' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 67.107912][ T8804] ================================================================== [ 67.107956][ T8804] BUG: KASAN: null-ptr-deref in do_con_write+0x94d2/0xf360 [ 67.107966][ T8804] Read of size 4294967294 at addr 0000000000000012 by task syz-executor662/8804 [ 67.107969][ T8804] [ 67.107980][ T8804] CPU: 0 PID: 8804 Comm: syz-executor662 Not tainted 5.6.0-rc1-syzkaller #0 [ 67.107986][ T8804] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.107990][ T8804] Call Trace: [ 67.108001][ T8804] dump_stack+0x1fb/0x318 [ 67.108019][ T8804] __kasan_report+0x167/0x1c0 [ 67.108030][ T8804] ? do_con_write+0x94d2/0xf360 [ 67.108040][ T8804] ? __atomic_notifier_call_chain+0x2cc/0x2f0 [ 67.108047][ T8804] ? do_con_write+0x94d2/0xf360 [ 67.108057][ T8804] kasan_report+0x26/0x50 [ 67.108065][ T8804] ? __atomic_notifier_call_chain+0x2cc/0x2f0 [ 67.108075][ T8804] check_memory_region+0x2b6/0x2f0 [ 67.108083][ T8804] ? do_con_write+0x94d2/0xf360 [ 67.108093][ T8804] memcpy+0x28/0x60 [ 67.108107][ T8804] do_con_write+0x94d2/0xf360 [ 67.108202][ T8804] ? _raw_spin_unlock_irqrestore+0x72/0xe0 [ 67.108227][ T8804] ? _raw_spin_unlock_irqrestore+0xb7/0xe0 [ 67.108245][ T8804] con_write+0x25/0x40 [ 67.108259][ T8804] n_tty_write+0xd0c/0x1200 [ 67.108300][ T8804] ? wait_woken+0x230/0x230 [ 67.108318][ T8804] tty_write+0x5a1/0x950 [ 67.108330][ T8804] ? n_tty_read+0x1bc0/0x1bc0 [ 67.108348][ T8804] ? redirected_tty_write+0xb0/0xb0 [ 67.108362][ T8804] __vfs_write+0xb8/0x740 [ 67.108381][ T8804] ? security_file_permission+0x147/0x340 [ 67.108397][ T8804] ? rw_verify_area+0x1c2/0x360 [ 67.108415][ T8804] vfs_write+0x270/0x580 [ 67.108438][ T8804] ksys_write+0x117/0x220 [ 67.108458][ T8804] __x64_sys_write+0x7b/0x90 [ 67.108474][ T8804] do_syscall_64+0xf7/0x1c0 [ 67.108491][ T8804] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.108499][ T8804] RIP: 0033:0x4404f9 [ 67.108508][ T8804] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 67.108513][ T8804] RSP: 002b:00007fffb1720718 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 67.108523][ T8804] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404f9 [ 67.108529][ T8804] RDX: 0000000000000078 RSI: 0000000020000140 RDI: 0000000000000004 [ 67.108535][ T8804] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 67.108541][ T8804] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401de0 [ 67.108546][ T8804] R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000 [ 67.108574][ T8804] ================================================================== [ 67.108578][ T8804] Disabling lock debugging due to kernel taint [ 67.108583][ T8804] Kernel panic - not syncing: panic_on_warn set ... [ 67.108594][ T8804] CPU: 0 PID: 8804 Comm: syz-executor662 Tainted: G B 5.6.0-rc1-syzkaller #0 [ 67.108599][ T8804] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.108602][ T8804] Call Trace: [ 67.108611][ T8804] dump_stack+0x1fb/0x318 [ 67.108625][ T8804] panic+0x264/0x7a9 [ 67.108633][ T8804] ? __kasan_report+0x193/0x1c0 [ 67.108642][ T8804] ? trace_hardirqs_on+0x34/0x80 [ 67.108655][ T8804] __kasan_report+0x1b9/0x1c0 [ 67.108667][ T8804] ? do_con_write+0x94d2/0xf360 [ 67.108675][ T8804] ? __atomic_notifier_call_chain+0x2cc/0x2f0 [ 67.108683][ T8804] ? do_con_write+0x94d2/0xf360 [ 67.108693][ T8804] kasan_report+0x26/0x50 [ 67.108700][ T8804] ? __atomic_notifier_call_chain+0x2cc/0x2f0 [ 67.108709][ T8804] check_memory_region+0x2b6/0x2f0 [ 67.108717][ T8804] ? do_con_write+0x94d2/0xf360 [ 67.108725][ T8804] memcpy+0x28/0x60 [ 67.108734][ T8804] do_con_write+0x94d2/0xf360 [ 67.108780][ T8804] ? _raw_spin_unlock_irqrestore+0x72/0xe0 [ 67.108794][ T8804] ? _raw_spin_unlock_irqrestore+0xb7/0xe0 [ 67.108805][ T8804] con_write+0x25/0x40 [ 67.108823][ T8804] n_tty_write+0xd0c/0x1200 [ 67.108845][ T8804] ? wait_woken+0x230/0x230 [ 67.108857][ T8804] tty_write+0x5a1/0x950 [ 67.108865][ T8804] ? n_tty_read+0x1bc0/0x1bc0 [ 67.108878][ T8804] ? redirected_tty_write+0xb0/0xb0 [ 67.108888][ T8804] __vfs_write+0xb8/0x740 [ 67.108901][ T8804] ? security_file_permission+0x147/0x340 [ 67.108913][ T8804] ? rw_verify_area+0x1c2/0x360 [ 67.108925][ T8804] vfs_write+0x270/0x580 [ 67.108940][ T8804] ksys_write+0x117/0x220 [ 67.108953][ T8804] __x64_sys_write+0x7b/0x90 [ 67.108966][ T8804] do_syscall_64+0xf7/0x1c0 [ 67.108979][ T8804] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.108985][ T8804] RIP: 0033:0x4404f9 [ 67.108994][ T8804] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 67.108998][ T8804] RSP: 002b:00007fffb1720718 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 67.109007][ T8804] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404f9 [ 67.109012][ T8804] RDX: 0000000000000078 RSI: 0000000020000140 RDI: 0000000000000004 [ 67.109017][ T8804] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 67.109022][ T8804] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401de0 [ 67.109026][ T8804] R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000 [ 67.110494][ T8804] Kernel Offset: disabled [ 67.628051][ T8804] Rebooting in 86400 seconds..