[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 78.119490][ T27] audit: type=1800 audit(1577978997.368:25): pid=9093 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 78.139317][ T27] audit: type=1800 audit(1577978997.368:26): pid=9093 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 78.186838][ T27] audit: type=1800 audit(1577978997.378:27): pid=9093 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 '10.128.0.126' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 571.999823][ T9949] ================================================================== [ 571.999993][ T9949] BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x270f/0x2b70 [ 572.000006][ T9949] Read of size 1 at addr ffff8880a33a8008 by task syz-executor006/9949 [ 572.000009][ T9949] [ 572.000024][ T9949] CPU: 1 PID: 9949 Comm: syz-executor006 Not tainted 5.5.0-rc4-syzkaller #0 [ 572.000032][ T9949] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 572.000037][ T9949] Call Trace: [ 572.000078][ T9949] dump_stack+0x197/0x210 [ 572.000096][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.000156][ T9949] print_address_description.constprop.0.cold+0xd4/0x30b [ 572.000173][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.000189][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.000204][ T9949] __kasan_report.cold+0x1b/0x41 [ 572.000223][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.000240][ T9949] kasan_report+0x12/0x20 [ 572.000257][ T9949] __asan_report_load1_noabort+0x14/0x20 [ 572.000273][ T9949] n_tty_receive_buf_common+0x270f/0x2b70 [ 572.000287][ T9949] ? __kasan_check_read+0x11/0x20 [ 572.000324][ T9949] n_tty_receive_buf2+0x34/0x40 [ 572.000344][ T9949] tty_ldisc_receive_buf+0xad/0x1c0 [ 572.000379][ T9949] ? add_wait_queue+0x112/0x170 [ 572.000395][ T9949] ? n_tty_receive_buf_common+0x2b70/0x2b70 [ 572.000434][ T9949] paste_selection+0x1ff/0x460 [ 572.000453][ T9949] ? vcs_remove_sysfs+0x60/0x60 [ 572.000486][ T9949] ? lock_downgrade+0x920/0x920 [ 572.000554][ T9949] ? wake_up_q+0x140/0x140 [ 572.000603][ T9949] tioclinux+0x133/0x480 [ 572.000624][ T9949] vt_ioctl+0x1a41/0x26d0 [ 572.000639][ T9949] ? complete_change_console+0x3a0/0x3a0 [ 572.165732][ T9949] ? lock_downgrade+0x920/0x920 [ 572.165752][ T9949] ? rwlock_bug.part.0+0x90/0x90 [ 572.176529][ T9949] ? tomoyo_path_number_perm+0x214/0x520 [ 572.176548][ T9949] ? find_held_lock+0x35/0x130 [ 572.187368][ T9949] ? tomoyo_path_number_perm+0x214/0x520 [ 572.187449][ T9949] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 572.187469][ T9949] ? tty_jobctrl_ioctl+0x50/0xd40 [ 572.204857][ T9949] ? complete_change_console+0x3a0/0x3a0 [ 572.204877][ T9949] tty_ioctl+0xa37/0x14f0 [ 572.204894][ T9949] ? tty_vhangup+0x30/0x30 [ 572.219308][ T9949] ? tomoyo_path_number_perm+0x454/0x520 [ 572.219329][ T9949] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 572.219347][ T9949] ? tomoyo_path_number_perm+0x25e/0x520 [ 572.237557][ T9949] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 572.237590][ T9949] ? tty_vhangup+0x30/0x30 [ 572.247887][ T9949] do_vfs_ioctl+0x977/0x14e0 [ 572.247909][ T9949] ? compat_ioctl_preallocate+0x220/0x220 [ 572.258233][ T9949] ? kmem_cache_free+0x26b/0x320 [ 572.258254][ T9949] ? putname+0xf4/0x130 [ 572.267565][ T9949] ? do_sys_open+0x31d/0x5d0 [ 572.267587][ T9949] ? tomoyo_file_ioctl+0x23/0x30 [ 572.277169][ T9949] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 572.277248][ T9949] ? security_file_ioctl+0x8d/0xc0 [ 572.288923][ T9949] ksys_ioctl+0xab/0xd0 [ 572.288944][ T9949] __x64_sys_ioctl+0x73/0xb0 [ 572.297781][ T9949] do_syscall_64+0xfa/0x790 [ 572.297836][ T9949] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 572.297848][ T9949] RIP: 0033:0x441409 [ 572.297864][ T9949] Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 572.297870][ T9949] RSP: 002b:00007fffcdaaac38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 572.297883][ T9949] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409 [ 572.297891][ T9949] RDX: 0000000020000100 RSI: 000000000000541c RDI: 0000000000000004 [ 572.297898][ T9949] RBP: 000000000008b9ed R08: 000000000000000e R09: 00000000004002c8 [ 572.297906][ T9949] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402180 [ 572.297914][ T9949] R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 [ 572.297933][ T9949] [ 572.297940][ T9949] Allocated by task 9942: [ 572.297953][ T9949] save_stack+0x23/0x90 [ 572.297966][ T9949] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 572.297976][ T9949] kasan_kmalloc+0x9/0x10 [ 572.297987][ T9949] __kmalloc+0x163/0x770 [ 572.298001][ T9949] set_selection_kernel+0x872/0x13b0 [ 572.298012][ T9949] set_selection_user+0x95/0xd9 [ 572.298025][ T9949] tioclinux+0x11c/0x480 [ 572.298035][ T9949] vt_ioctl+0x1a41/0x26d0 [ 572.298048][ T9949] tty_ioctl+0xa37/0x14f0 [ 572.298060][ T9949] do_vfs_ioctl+0x977/0x14e0 [ 572.298070][ T9949] ksys_ioctl+0xab/0xd0 [ 572.298081][ T9949] __x64_sys_ioctl+0x73/0xb0 [ 572.298094][ T9949] do_syscall_64+0xfa/0x790 [ 572.298108][ T9949] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 572.298112][ T9949] [ 572.298119][ T9949] Freed by task 9946: [ 572.298140][ T9949] save_stack+0x23/0x90 [ 572.298153][ T9949] __kasan_slab_free+0x102/0x150 [ 572.298165][ T9949] kasan_slab_free+0xe/0x10 [ 572.298174][ T9949] kfree+0x10a/0x2c0 [ 572.298185][ T9949] set_selection_kernel+0x88f/0x13b0 [ 572.298197][ T9949] set_selection_user+0x95/0xd9 [ 572.298210][ T9949] tioclinux+0x11c/0x480 [ 572.298219][ T9949] vt_ioctl+0x1a41/0x26d0 [ 572.298231][ T9949] tty_ioctl+0xa37/0x14f0 [ 572.298242][ T9949] do_vfs_ioctl+0x977/0x14e0 [ 572.298253][ T9949] ksys_ioctl+0xab/0xd0 [ 572.298265][ T9949] __x64_sys_ioctl+0x73/0xb0 [ 572.298280][ T9949] do_syscall_64+0xfa/0x790 [ 572.298295][ T9949] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 572.298299][ T9949] [ 572.298309][ T9949] The buggy address belongs to the object at ffff8880a33a8000 [ 572.298309][ T9949] which belongs to the cache kmalloc-8k of size 8192 [ 572.298321][ T9949] The buggy address is located 8 bytes inside of [ 572.298321][ T9949] 8192-byte region [ffff8880a33a8000, ffff8880a33aa000) [ 572.298325][ T9949] The buggy address belongs to the page: [ 572.298340][ T9949] page:ffffea00028cea00 refcount:1 mapcount:0 mapping:ffff8880aa4021c0 index:0x0 compound_mapcount: 0 [ 572.298358][ T9949] raw: 00fffe0000010200 ffffea0002947208 ffffea00027ef108 ffff8880aa4021c0 [ 572.298374][ T9949] raw: 0000000000000000 ffff8880a33a8000 0000000100000001 0000000000000000 [ 572.298380][ T9949] page dumped because: kasan: bad access detected [ 572.298383][ T9949] [ 572.298388][ T9949] Memory state around the buggy address: [ 572.298400][ T9949] ffff8880a33a7f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 572.298412][ T9949] ffff8880a33a7f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 572.298423][ T9949] >ffff8880a33a8000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 572.298429][ T9949] ^ [ 572.298440][ T9949] ffff8880a33a8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 572.298451][ T9949] ffff8880a33a8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 572.298456][ T9949] ================================================================== [ 572.298460][ T9949] Disabling lock debugging due to kernel taint [ 572.299733][ T9949] Kernel panic - not syncing: panic_on_warn set ... [ 572.299749][ T9949] CPU: 1 PID: 9949 Comm: syz-executor006 Tainted: G B 5.5.0-rc4-syzkaller #0 [ 572.299756][ T9949] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 572.299760][ T9949] Call Trace: [ 572.299777][ T9949] dump_stack+0x197/0x210 [ 572.299850][ T9949] panic+0x2e3/0x75c [ 572.299866][ T9949] ? add_taint.cold+0x16/0x16 [ 572.299890][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.299928][ T9949] ? preempt_schedule+0x4b/0x60 [ 572.299946][ T9949] ? ___preempt_schedule+0x16/0x18 [ 572.300004][ T9949] ? trace_hardirqs_on+0x5e/0x240 [ 572.300022][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.300037][ T9949] end_report+0x47/0x4f [ 572.300053][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.300068][ T9949] __kasan_report.cold+0xe/0x41 [ 572.300085][ T9949] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 572.300100][ T9949] kasan_report+0x12/0x20 [ 572.300122][ T9949] __asan_report_load1_noabort+0x14/0x20 [ 572.300138][ T9949] n_tty_receive_buf_common+0x270f/0x2b70 [ 572.300153][ T9949] ? __kasan_check_read+0x11/0x20 [ 572.300179][ T9949] n_tty_receive_buf2+0x34/0x40 [ 572.300196][ T9949] tty_ldisc_receive_buf+0xad/0x1c0 [ 572.300211][ T9949] ? add_wait_queue+0x112/0x170 [ 572.300231][ T9949] ? n_tty_receive_buf_common+0x2b70/0x2b70 [ 572.300246][ T9949] paste_selection+0x1ff/0x460 [ 572.300261][ T9949] ? vcs_remove_sysfs+0x60/0x60 [ 572.300277][ T9949] ? lock_downgrade+0x920/0x920 [ 572.300293][ T9949] ? wake_up_q+0x140/0x140 [ 572.300311][ T9949] tioclinux+0x133/0x480 [ 572.300325][ T9949] vt_ioctl+0x1a41/0x26d0 [ 572.300340][ T9949] ? complete_change_console+0x3a0/0x3a0 [ 572.300354][ T9949] ? lock_downgrade+0x920/0x920 [ 572.300369][ T9949] ? rwlock_bug.part.0+0x90/0x90 [ 572.300386][ T9949] ? tomoyo_path_number_perm+0x214/0x520 [ 572.300400][ T9949] ? find_held_lock+0x35/0x130 [ 572.300415][ T9949] ? tomoyo_path_number_perm+0x214/0x520 [ 572.300431][ T9949] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 572.300446][ T9949] ? tty_jobctrl_ioctl+0x50/0xd40 [ 572.300460][ T9949] ? complete_change_console+0x3a0/0x3a0 [ 572.300476][ T9949] tty_ioctl+0xa37/0x14f0 [ 572.300491][ T9949] ? tty_vhangup+0x30/0x30 [ 572.300506][ T9949] ? tomoyo_path_number_perm+0x454/0x520 [ 572.300523][ T9949] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 572.300538][ T9949] ? tomoyo_path_number_perm+0x25e/0x520 [ 572.300554][ T9949] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 572.300578][ T9949] ? tty_vhangup+0x30/0x30 [ 572.300594][ T9949] do_vfs_ioctl+0x977/0x14e0 [ 572.300617][ T9949] ? compat_ioctl_preallocate+0x220/0x220 [ 572.300631][ T9949] ? kmem_cache_free+0x26b/0x320 [ 572.300648][ T9949] ? putname+0xf4/0x130 [ 572.300663][ T9949] ? do_sys_open+0x31d/0x5d0 [ 572.300679][ T9949] ? tomoyo_file_ioctl+0x23/0x30 [ 572.300696][ T9949] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 572.300711][ T9949] ? security_file_ioctl+0x8d/0xc0 [ 572.300726][ T9949] ksys_ioctl+0xab/0xd0 [ 572.300741][ T9949] __x64_sys_ioctl+0x73/0xb0 [ 572.300757][ T9949] do_syscall_64+0xfa/0x790 [ 572.300773][ T9949] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 572.300785][ T9949] RIP: 0033:0x441409 [ 572.300801][ T9949] Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 572.300811][ T9949] RSP: 002b:00007fffcdaaac38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 572.300832][ T9949] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409 [ 572.300844][ T9949] RDX: 0000000020000100 RSI: 000000000000541c RDI: 0000000000000004 [ 572.300855][ T9949] RBP: 000000000008b9ed R08: 000000000000000e R09: 00000000004002c8 [ 572.300867][ T9949] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402180 [ 572.300878][ T9949] R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 [ 572.302494][ T9949] Kernel Offset: disabled