[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 65.991674][ T27] audit: type=1800 audit(1577045149.929:25): pid=9187 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 66.012271][ T27] audit: type=1800 audit(1577045149.929:26): pid=9187 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 66.069808][ T27] audit: type=1800 audit(1577045149.929:27): pid=9187 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 '10.128.0.9' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 85.685704][ T9354] ================================================================== [ 85.693961][ T9354] BUG: KASAN: use-after-free in try_to_grab_pending+0x115/0x910 [ 85.701589][ T9354] Write of size 8 at addr ffff8880a3890008 by task syz-executor778/9354 [ 85.709899][ T9354] [ 85.712236][ T9354] CPU: 1 PID: 9354 Comm: syz-executor778 Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 [ 85.722118][ T9354] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 85.732173][ T9354] Call Trace: [ 85.735472][ T9354] dump_stack+0x197/0x210 [ 85.739822][ T9354] ? try_to_grab_pending+0x115/0x910 [ 85.745121][ T9354] print_address_description.constprop.0.cold+0xd4/0x30b [ 85.752149][ T9354] ? try_to_grab_pending+0x115/0x910 [ 85.757445][ T9354] ? try_to_grab_pending+0x115/0x910 [ 85.762737][ T9354] __kasan_report.cold+0x1b/0x41 [ 85.767688][ T9354] ? try_to_grab_pending+0x115/0x910 [ 85.772988][ T9354] kasan_report+0x12/0x20 [ 85.777860][ T9354] check_memory_region+0x134/0x1a0 [ 85.782989][ T9354] __kasan_check_write+0x14/0x20 [ 85.787937][ T9354] try_to_grab_pending+0x115/0x910 [ 85.793057][ T9354] ? __kasan_check_read+0x11/0x20 [ 85.798091][ T9354] __cancel_work_timer+0xc4/0x540 [ 85.803163][ T9354] ? mod_delayed_work_on+0x200/0x200 [ 85.808461][ T9354] ? get_work_pool+0x1b0/0x1b0 [ 85.813867][ T9354] cancel_work_sync+0x18/0x20 [ 85.818762][ T9354] tty_buffer_cancel_work+0x16/0x20 [ 85.823971][ T9354] release_tty+0x261/0x470 [ 85.828397][ T9354] tty_release_struct+0x3c/0x50 executing program executing program [ 85.833257][ T9354] tty_release+0xbcb/0xe90 [ 85.837687][ T9354] __fput+0x2ff/0x890 [ 85.841676][ T9354] ? do_tty_hangup+0x30/0x30 [ 85.846285][ T9354] ____fput+0x16/0x20 [ 85.850278][ T9354] task_work_run+0x145/0x1c0 [ 85.854871][ T9354] do_exit+0x909/0x2f20 [ 85.859013][ T9354] ? mm_update_next_owner+0x7c0/0x7c0 [ 85.864366][ T9354] ? down_read_non_owner+0x490/0x490 [ 85.869643][ T9354] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 85.875866][ T9354] ? handle_mm_fault+0x4ab/0xa50 [ 85.880789][ T9354] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 85.886335][ T9354] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 85.891778][ T9354] do_group_exit+0x135/0x360 [ 85.896439][ T9354] __x64_sys_exit_group+0x44/0x50 [ 85.901447][ T9354] do_syscall_64+0xfa/0x790 [ 85.905934][ T9354] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 85.911803][ T9354] RIP: 0033:0x43ff38 [ 85.915688][ T9354] 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 [ 85.935279][ T9354] RSP: 002b:00007ffd86fe1898 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 85.943670][ T9354] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 85.951621][ T9354] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 85.959660][ T9354] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 85.967618][ T9354] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 85.975579][ T9354] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 85.983566][ T9354] [ 85.985881][ T9354] Allocated by task 9354: [ 85.990199][ T9354] save_stack+0x23/0x90 [ 85.994428][ T9354] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 86.000073][ T9354] kasan_kmalloc+0x9/0x10 [ 86.004411][ T9354] kmem_cache_alloc_trace+0x158/0x790 [ 86.009780][ T9354] vc_allocate+0x1fc/0x760 [ 86.014177][ T9354] con_install+0x52/0x410 [ 86.018486][ T9354] tty_init_dev+0xf9/0x470 [ 86.022880][ T9354] tty_open+0x4a5/0xbb0 [ 86.027021][ T9354] chrdev_open+0x245/0x6b0 [ 86.031429][ T9354] do_dentry_open+0x4ca/0x1350 [ 86.036259][ T9354] vfs_open+0xa0/0xd0 [ 86.040222][ T9354] path_openat+0x12fd/0x34d0 [ 86.044787][ T9354] do_filp_open+0x192/0x260 [ 86.049266][ T9354] do_sys_openat2+0x633/0x840 [ 86.053943][ T9354] do_sys_open+0xfc/0x190 [ 86.058265][ T9354] __x64_sys_open+0x7e/0xc0 [ 86.062770][ T9354] do_syscall_64+0xfa/0x790 [ 86.067280][ T9354] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 86.073146][ T9354] [ 86.075453][ T9354] Freed by task 9352: [ 86.079422][ T9354] save_stack+0x23/0x90 [ 86.084696][ T9354] __kasan_slab_free+0x102/0x150 [ 86.089611][ T9354] kasan_slab_free+0xe/0x10 [ 86.094123][ T9354] kfree+0x10a/0x2c0 [ 86.097999][ T9354] vt_disallocate_all+0x2bd/0x3e0 [ 86.103002][ T9354] vt_ioctl+0xc38/0x26d0 [ 86.107242][ T9354] tty_ioctl+0xa37/0x14f0 [ 86.111561][ T9354] ksys_ioctl+0x123/0x180 [ 86.115954][ T9354] __x64_sys_ioctl+0x73/0xb0 [ 86.120540][ T9354] do_syscall_64+0xfa/0x790 [ 86.125028][ T9354] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 86.130910][ T9354] [ 86.133236][ T9354] The buggy address belongs to the object at ffff8880a3890000 [ 86.133236][ T9354] which belongs to the cache kmalloc-2k of size 2048 [ 86.147266][ T9354] The buggy address is located 8 bytes inside of [ 86.147266][ T9354] 2048-byte region [ffff8880a3890000, ffff8880a3890800) [ 86.160597][ T9354] The buggy address belongs to the page: [ 86.166209][ T9354] page:ffffea00028e2400 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 [ 86.175396][ T9354] raw: 00fffe0000000200 ffffea00028d24c8 ffffea00025e5c88 ffff8880aa400e00 [ 86.183971][ T9354] raw: 0000000000000000 ffff8880a3890000 0000000100000001 0000000000000000 [ 86.192530][ T9354] page dumped because: kasan: bad access detected [ 86.198917][ T9354] [ 86.201224][ T9354] Memory state around the buggy address: [ 86.206832][ T9354] ffff8880a388ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 86.214888][ T9354] ffff8880a388ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 86.222945][ T9354] >ffff8880a3890000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 86.231707][ T9354] ^ [ 86.236031][ T9354] ffff8880a3890080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 86.244080][ T9354] ffff8880a3890100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 86.252121][ T9354] ================================================================== [ 86.260158][ T9354] Disabling lock debugging due to kernel taint [ 86.266286][ T9354] Kernel panic - not syncing: panic_on_warn set ... [ 86.272911][ T9354] CPU: 1 PID: 9354 Comm: syz-executor778 Tainted: G B 5.5.0-rc2-next-20191220-syzkaller #0 [ 86.284181][ T9354] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 86.294224][ T9354] Call Trace: [ 86.297556][ T9354] dump_stack+0x197/0x210 [ 86.301878][ T9354] panic+0x2e3/0x75c [ 86.305804][ T9354] ? add_taint.cold+0x16/0x16 [ 86.310509][ T9354] ? try_to_grab_pending+0x115/0x910 [ 86.315782][ T9354] ? trace_hardirqs_off+0x62/0x240 [ 86.320960][ T9354] ? trace_hardirqs_off+0x59/0x240 [ 86.326098][ T9354] ? try_to_grab_pending+0x115/0x910 [ 86.331369][ T9354] end_report+0x47/0x4f [ 86.335502][ T9354] ? try_to_grab_pending+0x115/0x910 [ 86.340775][ T9354] __kasan_report.cold+0xe/0x41 [ 86.345622][ T9354] ? try_to_grab_pending+0x115/0x910 [ 86.351208][ T9354] kasan_report+0x12/0x20 [ 86.355568][ T9354] check_memory_region+0x134/0x1a0 [ 86.360676][ T9354] __kasan_check_write+0x14/0x20 [ 86.365611][ T9354] try_to_grab_pending+0x115/0x910 [ 86.370706][ T9354] ? __kasan_check_read+0x11/0x20 [ 86.375716][ T9354] __cancel_work_timer+0xc4/0x540 [ 86.380734][ T9354] ? mod_delayed_work_on+0x200/0x200 [ 86.386001][ T9354] ? get_work_pool+0x1b0/0x1b0 [ 86.390759][ T9354] cancel_work_sync+0x18/0x20 [ 86.396383][ T9354] tty_buffer_cancel_work+0x16/0x20 [ 86.401572][ T9354] release_tty+0x261/0x470 [ 86.406018][ T9354] tty_release_struct+0x3c/0x50 [ 86.410854][ T9354] tty_release+0xbcb/0xe90 [ 86.415307][ T9354] __fput+0x2ff/0x890 [ 86.419320][ T9354] ? do_tty_hangup+0x30/0x30 [ 86.423895][ T9354] ____fput+0x16/0x20 [ 86.427859][ T9354] task_work_run+0x145/0x1c0 [ 86.432433][ T9354] do_exit+0x909/0x2f20 [ 86.436708][ T9354] ? mm_update_next_owner+0x7c0/0x7c0 [ 86.442071][ T9354] ? down_read_non_owner+0x490/0x490 [ 86.447338][ T9354] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 86.453557][ T9354] ? handle_mm_fault+0x4ab/0xa50 [ 86.458477][ T9354] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 86.463918][ T9354] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 86.469370][ T9354] do_group_exit+0x135/0x360 [ 86.474264][ T9354] __x64_sys_exit_group+0x44/0x50 [ 86.479339][ T9354] do_syscall_64+0xfa/0x790 [ 86.484273][ T9354] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 86.490183][ T9354] RIP: 0033:0x43ff38 [ 86.494060][ T9354] 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 [ 86.513688][ T9354] RSP: 002b:00007ffd86fe1898 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 86.522079][ T9354] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 86.530034][ T9354] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 86.538071][ T9354] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 86.546053][ T9354] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 86.554016][ T9354] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 86.563386][ T9354] Kernel Offset: disabled [ 86.567712][ T9354] Rebooting in 86400 seconds..