[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 70.697389][ T27] audit: type=1800 audit(1585826331.332:25): pid=9315 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 70.724908][ T27] audit: type=1800 audit(1585826331.332:26): pid=9315 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 70.757515][ T27] audit: type=1800 audit(1585826331.342:27): pid=9315 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 '10.128.10.12' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 79.228089][ T9479] ================================================================== [ 79.228151][ T9479] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 79.228162][ T9479] Write of size 8 at addr ffff88809899f108 by task syz-executor341/9479 [ 79.228166][ T9479] [ 79.228180][ T9479] CPU: 1 PID: 9479 Comm: syz-executor341 Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 [ 79.228187][ T9479] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 79.228192][ T9479] Call Trace: [ 79.228209][ T9479] dump_stack+0x188/0x20d [ 79.228222][ T9479] ? con_shutdown+0x7f/0x90 [ 79.228236][ T9479] ? con_shutdown+0x7f/0x90 [ 79.228253][ T9479] print_address_description.constprop.0.cold+0xd3/0x315 [ 79.228265][ T9479] ? con_shutdown+0x7f/0x90 [ 79.228279][ T9479] ? con_shutdown+0x7f/0x90 [ 79.228289][ T9479] __kasan_report.cold+0x1a/0x32 [ 79.228308][ T9479] ? con_shutdown+0x7f/0x90 [ 79.228327][ T9479] kasan_report+0xe/0x20 [ 79.228340][ T9479] con_shutdown+0x7f/0x90 [ 79.228357][ T9479] ? update_region+0x140/0x140 [ 79.228370][ T9479] release_tty+0xca/0x450 [ 79.228388][ T9479] tty_release_struct+0x37/0x50 [ 79.228403][ T9479] tty_release+0xbc7/0xe90 [ 79.228429][ T9479] ? do_tty_hangup+0x30/0x30 [ 79.228442][ T9479] __fput+0x2da/0x850 [ 79.228469][ T9479] task_work_run+0x13f/0x1b0 [ 79.228489][ T9479] do_exit+0xb53/0x2e10 [ 79.228518][ T9479] ? mm_update_next_owner+0x7a0/0x7a0 [ 79.228532][ T9479] ? up_read+0x1a8/0x750 [ 79.228550][ T9479] ? down_read_nested+0x430/0x430 [ 79.228567][ T9479] ? handle_mm_fault+0x29e/0x660 [ 79.228586][ T9479] do_group_exit+0x125/0x340 [ 79.228602][ T9479] __x64_sys_exit_group+0x3a/0x50 [ 79.228616][ T9479] do_syscall_64+0xf6/0x790 [ 79.228636][ T9479] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 79.228645][ T9479] RIP: 0033:0x43ff38 [ 79.228655][ T9479] Code: Bad RIP value. [ 79.228661][ T9479] RSP: 002b:00007ffcbdeeef18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 79.228670][ T9479] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 79.228676][ T9479] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 79.228682][ T9479] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 79.228687][ T9479] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 79.228693][ T9479] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 79.228721][ T9479] [ 79.228726][ T9479] Allocated by task 9479: [ 79.228737][ T9479] save_stack+0x1b/0x40 [ 79.228746][ T9479] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 79.228756][ T9479] kmem_cache_alloc_trace+0x153/0x7d0 [ 79.228763][ T9479] vc_allocate+0x1e2/0x6e0 [ 79.228770][ T9479] con_install+0x4f/0x400 [ 79.228779][ T9479] tty_init_dev+0xf5/0x460 [ 79.228786][ T9479] tty_open+0x47f/0xb30 [ 79.228796][ T9479] chrdev_open+0x219/0x5c0 [ 79.228805][ T9479] do_dentry_open+0x49e/0x1250 [ 79.228814][ T9479] path_openat+0x122a/0x3230 [ 79.228823][ T9479] do_filp_open+0x192/0x260 [ 79.228832][ T9479] do_sys_openat2+0x54c/0x740 [ 79.228841][ T9479] do_sys_open+0xc3/0x140 [ 79.228850][ T9479] do_syscall_64+0xf6/0x790 [ 79.228859][ T9479] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 79.228861][ T9479] [ 79.228866][ T9479] Freed by task 9480: [ 79.228874][ T9479] save_stack+0x1b/0x40 [ 79.228883][ T9479] __kasan_slab_free+0xf7/0x140 [ 79.228891][ T9479] kfree+0x109/0x2b0 [ 79.228899][ T9479] vt_disallocate_all+0x283/0x370 [ 79.228907][ T9479] vt_ioctl+0x79e/0x2450 [ 79.228915][ T9479] tty_ioctl+0xedd/0x1440 [ 79.228923][ T9479] ksys_ioctl+0x11a/0x180 [ 79.228930][ T9479] __x64_sys_ioctl+0x6f/0xb0 [ 79.228939][ T9479] do_syscall_64+0xf6/0x790 [ 79.228948][ T9479] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 79.228950][ T9479] [ 79.228957][ T9479] The buggy address belongs to the object at ffff88809899f000 [ 79.228957][ T9479] which belongs to the cache kmalloc-2k of size 2048 [ 79.228966][ T9479] The buggy address is located 264 bytes inside of [ 79.228966][ T9479] 2048-byte region [ffff88809899f000, ffff88809899f800) [ 79.228969][ T9479] The buggy address belongs to the page: [ 79.228979][ T9479] page:ffffea00026267c0 refcount:1 mapcount:0 mapping:00000000befc4cbf index:0x0 [ 79.228986][ T9479] flags: 0xfffe0000000200(slab) [ 79.229000][ T9479] raw: 00fffe0000000200 ffffea000237d448 ffffea00026870c8 ffff8880aa000e00 [ 79.229011][ T9479] raw: 0000000000000000 ffff88809899f000 0000000100000001 0000000000000000 [ 79.229015][ T9479] page dumped because: kasan: bad access detected [ 79.229018][ T9479] [ 79.229021][ T9479] Memory state around the buggy address: [ 79.229029][ T9479] ffff88809899f000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 79.229036][ T9479] ffff88809899f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 79.229049][ T9479] >ffff88809899f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 79.229053][ T9479] ^ [ 79.229060][ T9479] ffff88809899f180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 79.229067][ T9479] ffff88809899f200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 79.229070][ T9479] ================================================================== [ 79.229074][ T9479] Disabling lock debugging due to kernel taint [ 79.229134][ T9479] Kernel panic - not syncing: panic_on_warn set ... [ 79.229148][ T9479] CPU: 1 PID: 9479 Comm: syz-executor341 Tainted: G B 5.6.0-rc3-next-20200228-syzkaller #0 [ 79.229154][ T9479] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 79.229157][ T9479] Call Trace: [ 79.229171][ T9479] dump_stack+0x188/0x20d [ 79.229185][ T9479] panic+0x2e3/0x75c [ 79.229196][ T9479] ? add_taint.cold+0x16/0x16 [ 79.229210][ T9479] ? preempt_schedule_common+0x5e/0xc0 [ 79.229222][ T9479] ? con_shutdown+0x7f/0x90 [ 79.229233][ T9479] ? ___preempt_schedule+0x16/0x18 [ 79.229244][ T9479] ? trace_hardirqs_on+0x55/0x220 [ 79.229257][ T9479] ? con_shutdown+0x7f/0x90 [ 79.229268][ T9479] end_report+0x43/0x49 [ 79.229279][ T9479] ? con_shutdown+0x7f/0x90 [ 79.229288][ T9479] __kasan_report.cold+0xd/0x32 [ 79.229303][ T9479] ? con_shutdown+0x7f/0x90 [ 79.229316][ T9479] kasan_report+0xe/0x20 [ 79.229327][ T9479] con_shutdown+0x7f/0x90 [ 79.229337][ T9479] ? update_region+0x140/0x140 [ 79.229348][ T9479] release_tty+0xca/0x450 [ 79.229362][ T9479] tty_release_struct+0x37/0x50 [ 79.229374][ T9479] tty_release+0xbc7/0xe90 [ 79.229392][ T9479] ? do_tty_hangup+0x30/0x30 [ 79.229402][ T9479] __fput+0x2da/0x850 [ 79.229420][ T9479] task_work_run+0x13f/0x1b0 [ 79.229434][ T9479] do_exit+0xb53/0x2e10 [ 79.229452][ T9479] ? mm_update_next_owner+0x7a0/0x7a0 [ 79.229464][ T9479] ? up_read+0x1a8/0x750 [ 79.229478][ T9479] ? down_read_nested+0x430/0x430 [ 79.229491][ T9479] ? handle_mm_fault+0x29e/0x660 [ 79.229505][ T9479] do_group_exit+0x125/0x340 [ 79.229518][ T9479] __x64_sys_exit_group+0x3a/0x50 [ 79.229530][ T9479] do_syscall_64+0xf6/0x790 [ 79.229543][ T9479] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 79.229551][ T9479] RIP: 0033:0x43ff38 [ 79.229562][ T9479] 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 [ 79.229568][ T9479] RSP: 002b:00007ffcbdeeef18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 79.229579][ T9479] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 79.229585][ T9479] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 79.229592][ T9479] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 79.229598][ T9479] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 79.229604][ T9479] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 79.230965][ T9479] Kernel Offset: disabled [ 79.979690][ T9479] Rebooting in 86400 seconds..