[ 64.383986][ T27] audit: type=1800 audit(1584285976.365:25): pid=9346 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 64.417760][ T27] audit: type=1800 audit(1584285976.365:26): pid=9346 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 64.453271][ T27] audit: type=1800 audit(1584285976.365:27): pid=9346 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. [ 64.833173][ T9412] sshd (9412) used greatest stack depth: 23216 bytes left [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.251' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 75.906597][ T9509] ================================================================== [ 75.906654][ T9509] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 75.906666][ T9509] Write of size 8 at addr ffff8880946f2108 by task syz-executor128/9509 [ 75.906670][ T9509] [ 75.906684][ T9509] CPU: 1 PID: 9509 Comm: syz-executor128 Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 [ 75.906691][ T9509] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.906696][ T9509] Call Trace: [ 75.906712][ T9509] dump_stack+0x188/0x20d [ 75.906727][ T9509] ? con_shutdown+0x7f/0x90 [ 75.906742][ T9509] ? con_shutdown+0x7f/0x90 [ 75.906758][ T9509] print_address_description.constprop.0.cold+0xd3/0x315 [ 75.906771][ T9509] ? con_shutdown+0x7f/0x90 [ 75.906785][ T9509] ? con_shutdown+0x7f/0x90 [ 75.906795][ T9509] __kasan_report.cold+0x1a/0x32 [ 75.906812][ T9509] ? con_shutdown+0x7f/0x90 [ 75.906831][ T9509] kasan_report+0xe/0x20 [ 75.906844][ T9509] con_shutdown+0x7f/0x90 [ 75.906856][ T9509] ? update_region+0x140/0x140 [ 75.906874][ T9509] release_tty+0xca/0x450 [ 75.906891][ T9509] tty_release_struct+0x37/0x50 [ 75.906906][ T9509] tty_release+0xbc7/0xe90 [ 75.906933][ T9509] ? do_tty_hangup+0x30/0x30 [ 75.906945][ T9509] __fput+0x2da/0x850 [ 75.906972][ T9509] task_work_run+0x13f/0x1b0 [ 75.906991][ T9509] do_exit+0xb53/0x2e10 [ 75.907018][ T9509] ? mm_update_next_owner+0x7a0/0x7a0 [ 75.907032][ T9509] ? up_read+0x1a8/0x750 [ 75.907051][ T9509] ? down_read_nested+0x430/0x430 [ 75.907069][ T9509] ? handle_mm_fault+0x29e/0x660 [ 75.907088][ T9509] do_group_exit+0x125/0x340 [ 75.907106][ T9509] __x64_sys_exit_group+0x3a/0x50 [ 75.907121][ T9509] do_syscall_64+0xf6/0x790 [ 75.907140][ T9509] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.907150][ T9509] RIP: 0033:0x43ff38 [ 75.907164][ T9509] 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 [ 75.907171][ T9509] RSP: 002b:00007ffe30d34b68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 75.907183][ T9509] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 75.907190][ T9509] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 75.907198][ T9509] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 75.907205][ T9509] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 75.907212][ T9509] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 75.907241][ T9509] [ 75.907247][ T9509] Allocated by task 9509: [ 75.907259][ T9509] save_stack+0x1b/0x40 [ 75.907271][ T9509] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 75.907282][ T9509] kmem_cache_alloc_trace+0x153/0x7d0 [ 75.907292][ T9509] vc_allocate+0x1e2/0x6e0 [ 75.907301][ T9509] con_install+0x4f/0x400 [ 75.907318][ T9509] tty_init_dev+0xf5/0x460 [ 75.907326][ T9509] tty_open+0x47f/0xb30 [ 75.907338][ T9509] chrdev_open+0x219/0x5c0 [ 75.907350][ T9509] do_dentry_open+0x49e/0x1250 [ 75.907361][ T9509] path_openat+0x122a/0x3230 [ 75.907372][ T9509] do_filp_open+0x192/0x260 [ 75.907384][ T9509] do_sys_openat2+0x54c/0x740 [ 75.907394][ T9509] do_sys_open+0xc3/0x140 [ 75.907405][ T9509] do_syscall_64+0xf6/0x790 [ 75.907416][ T9509] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.907419][ T9509] [ 75.907425][ T9509] Freed by task 9510: [ 75.907436][ T9509] save_stack+0x1b/0x40 [ 75.907447][ T9509] __kasan_slab_free+0xf7/0x140 [ 75.907456][ T9509] kfree+0x109/0x2b0 [ 75.907466][ T9509] vt_disallocate_all+0x283/0x370 [ 75.907475][ T9509] vt_ioctl+0x79e/0x2450 [ 75.907486][ T9509] tty_ioctl+0xedd/0x1440 [ 75.907495][ T9509] ksys_ioctl+0x11a/0x180 [ 75.907505][ T9509] __x64_sys_ioctl+0x6f/0xb0 [ 75.907516][ T9509] do_syscall_64+0xf6/0x790 [ 75.907528][ T9509] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.907531][ T9509] [ 75.907540][ T9509] The buggy address belongs to the object at ffff8880946f2000 [ 75.907540][ T9509] which belongs to the cache kmalloc-2k of size 2048 [ 75.907550][ T9509] The buggy address is located 264 bytes inside of [ 75.907550][ T9509] 2048-byte region [ffff8880946f2000, ffff8880946f2800) [ 75.907554][ T9509] The buggy address belongs to the page: [ 75.907565][ T9509] page:ffffea000251bc80 refcount:1 mapcount:0 mapping:000000005180cbf4 index:0x0 [ 75.907574][ T9509] flags: 0xfffe0000000200(slab) [ 75.907590][ T9509] raw: 00fffe0000000200 ffffea0002517048 ffffea0002517748 ffff8880aa000e00 [ 75.907603][ T9509] raw: 0000000000000000 ffff8880946f2000 0000000100000001 0000000000000000 [ 75.907608][ T9509] page dumped because: kasan: bad access detected [ 75.907612][ T9509] [ 75.907615][ T9509] Memory state around the buggy address: [ 75.907625][ T9509] ffff8880946f2000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.907635][ T9509] ffff8880946f2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.907643][ T9509] >ffff8880946f2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.907648][ T9509] ^ [ 75.907656][ T9509] ffff8880946f2180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.907665][ T9509] ffff8880946f2200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.907669][ T9509] ================================================================== [ 75.907673][ T9509] Disabling lock debugging due to kernel taint [ 75.907890][ T9509] Kernel panic - not syncing: panic_on_warn set ... [ 75.907904][ T9509] CPU: 1 PID: 9509 Comm: syz-executor128 Tainted: G B 5.6.0-rc3-next-20200228-syzkaller #0 [ 75.907910][ T9509] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.907914][ T9509] Call Trace: [ 75.907928][ T9509] dump_stack+0x188/0x20d [ 75.907949][ T9509] panic+0x2e3/0x75c [ 75.907961][ T9509] ? add_taint.cold+0x16/0x16 [ 75.907972][ T9509] ? retint_kernel+0x2b/0x2b [ 75.907990][ T9509] ? trace_hardirqs_on+0x55/0x220 [ 75.908008][ T9509] ? con_shutdown+0x7f/0x90 [ 75.908018][ T9509] end_report+0x43/0x49 [ 75.908029][ T9509] ? con_shutdown+0x7f/0x90 [ 75.908039][ T9509] __kasan_report.cold+0xd/0x32 [ 75.908052][ T9509] ? con_shutdown+0x7f/0x90 [ 75.908066][ T9509] kasan_report+0xe/0x20 [ 75.908077][ T9509] con_shutdown+0x7f/0x90 [ 75.908088][ T9509] ? update_region+0x140/0x140 [ 75.908099][ T9509] release_tty+0xca/0x450 [ 75.908111][ T9509] tty_release_struct+0x37/0x50 [ 75.908124][ T9509] tty_release+0xbc7/0xe90 [ 75.908142][ T9509] ? do_tty_hangup+0x30/0x30 [ 75.908152][ T9509] __fput+0x2da/0x850 [ 75.908171][ T9509] task_work_run+0x13f/0x1b0 [ 75.908185][ T9509] do_exit+0xb53/0x2e10 [ 75.908203][ T9509] ? mm_update_next_owner+0x7a0/0x7a0 [ 75.908215][ T9509] ? up_read+0x1a8/0x750 [ 75.908230][ T9509] ? down_read_nested+0x430/0x430 [ 75.908244][ T9509] ? handle_mm_fault+0x29e/0x660 [ 75.908257][ T9509] do_group_exit+0x125/0x340 [ 75.908270][ T9509] __x64_sys_exit_group+0x3a/0x50 [ 75.908282][ T9509] do_syscall_64+0xf6/0x790 [ 75.908296][ T9509] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.908311][ T9509] RIP: 0033:0x43ff38 [ 75.908323][ T9509] 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 [ 75.908328][ T9509] RSP: 002b:00007ffe30d34b68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 75.908339][ T9509] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 75.908345][ T9509] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 75.908352][ T9509] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 75.908358][ T9509] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 75.908364][ T9509] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 75.909561][ T9509] Kernel Offset: disabled [ 76.655724][ T9509] Rebooting in 86400 seconds..