[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 86.871674][ T27] audit: type=1800 audit(1581965453.483:25): pid=9401 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 86.901775][ T27] audit: type=1800 audit(1581965453.493:26): pid=9401 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 86.956808][ T27] audit: type=1800 audit(1581965453.493:27): pid=9401 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 '10.128.0.189' (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 syzkaller login: [ 104.724722][ T9562] ================================================================== [ 104.732960][ T9562] BUG: KASAN: use-after-free in get_work_pool_id+0x1c/0xe0 [ 104.740164][ T9562] Read of size 8 at addr ffff8880a2d36008 by task syz-executor507/9562 [ 104.748399][ T9562] [ 104.750742][ T9562] CPU: 1 PID: 9562 Comm: syz-executor507 Not tainted 5.6.0-rc2-syzkaller #0 [ 104.759416][ T9562] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 104.769472][ T9562] Call Trace: [ 104.772775][ T9562] dump_stack+0x197/0x210 [ 104.777139][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 104.782012][ T9562] print_address_description.constprop.0.cold+0xd4/0x30b [ 104.789043][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 104.793906][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 104.798797][ T9562] __kasan_report.cold+0x1b/0x32 [ 104.804076][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 104.808949][ T9562] kasan_report+0x12/0x20 [ 104.813290][ T9562] check_memory_region+0x134/0x1a0 [ 104.818420][ T9562] __kasan_check_read+0x11/0x20 [ 104.823280][ T9562] get_work_pool_id+0x1c/0xe0 [ 104.827967][ T9562] __cancel_work_timer+0xfa/0x540 [ 104.833013][ T9562] ? console_unlock+0x7b3/0xf00 [ 104.838395][ T9562] ? mod_delayed_work_on+0x200/0x200 [ 104.843706][ T9562] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 104.849428][ T9562] ? console_unlock+0x81e/0xf00 [ 104.854305][ T9562] cancel_work_sync+0x18/0x20 [ 104.858991][ T9562] tty_buffer_cancel_work+0x16/0x20 [ 104.864199][ T9562] release_tty+0x261/0x470 [ 104.868634][ T9562] tty_release_struct+0x3c/0x50 [ 104.873493][ T9562] tty_release+0xbcb/0xe90 [ 104.877945][ T9562] __fput+0x2ff/0x890 [ 104.881947][ T9562] ? do_tty_hangup+0x30/0x30 [ 104.886559][ T9562] ____fput+0x16/0x20 [ 104.890554][ T9562] task_work_run+0x145/0x1c0 [ 104.895163][ T9562] do_exit+0xba9/0x2f50 [ 104.899350][ T9562] ? mm_update_next_owner+0x7c0/0x7c0 [ 104.904727][ T9562] ? up_read+0x1cd/0x810 [ 104.908988][ T9562] ? down_read_non_owner+0x490/0x490 [ 104.914282][ T9562] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 104.919755][ T9562] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 104.925227][ T9562] do_group_exit+0x135/0x360 [ 104.929834][ T9562] __x64_sys_exit_group+0x44/0x50 [ 104.934870][ T9562] do_syscall_64+0xfa/0x790 [ 104.939387][ T9562] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 104.945278][ T9562] RIP: 0033:0x43ff38 [ 104.949180][ T9562] Code: Bad RIP value. [ 104.953245][ T9562] RSP: 002b:00007fff706d7d78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 104.961658][ T9562] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 104.969640][ T9562] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 104.977608][ T9562] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 104.985580][ T9562] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 104.993666][ T9562] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 105.001706][ T9562] [ 105.004032][ T9562] Allocated by task 9562: [ 105.008349][ T9562] save_stack+0x23/0x90 [ 105.012489][ T9562] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 105.018109][ T9562] kasan_kmalloc+0x9/0x10 [ 105.022429][ T9562] kmem_cache_alloc_trace+0x158/0x790 [ 105.027789][ T9562] vc_allocate+0x1fc/0x760 [ 105.032193][ T9562] con_install+0x52/0x410 [ 105.036514][ T9562] tty_init_dev+0xf9/0x470 [ 105.040908][ T9562] tty_open+0x4a5/0xbb0 [ 105.045047][ T9562] chrdev_open+0x245/0x6b0 [ 105.049447][ T9562] do_dentry_open+0x4e6/0x1380 [ 105.054191][ T9562] vfs_open+0xa0/0xd0 [ 105.058167][ T9562] path_openat+0x12ee/0x3490 [ 105.062767][ T9562] do_filp_open+0x192/0x260 [ 105.067273][ T9562] do_sys_openat2+0x5eb/0x7e0 [ 105.071952][ T9562] do_sys_open+0xf2/0x180 [ 105.076259][ T9562] __x64_sys_open+0x7e/0xc0 [ 105.080769][ T9562] do_syscall_64+0xfa/0x790 [ 105.085266][ T9562] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 105.091200][ T9562] [ 105.093528][ T9562] Freed by task 9566: [ 105.097510][ T9562] save_stack+0x23/0x90 [ 105.101670][ T9562] __kasan_slab_free+0x102/0x150 [ 105.106608][ T9562] kasan_slab_free+0xe/0x10 [ 105.111210][ T9562] kfree+0x10a/0x2c0 [ 105.115104][ T9562] vt_disallocate_all+0x2bd/0x3e0 [ 105.120128][ T9562] vt_ioctl+0xc38/0x26d0 [ 105.124352][ T9562] tty_ioctl+0xa37/0x14f0 [ 105.128678][ T9562] ksys_ioctl+0x123/0x180 [ 105.132989][ T9562] __x64_sys_ioctl+0x73/0xb0 [ 105.137561][ T9562] do_syscall_64+0xfa/0x790 [ 105.142059][ T9562] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 105.147938][ T9562] [ 105.150260][ T9562] The buggy address belongs to the object at ffff8880a2d36000 [ 105.150260][ T9562] which belongs to the cache kmalloc-2k of size 2048 [ 105.164307][ T9562] The buggy address is located 8 bytes inside of [ 105.164307][ T9562] 2048-byte region [ffff8880a2d36000, ffff8880a2d36800) [ 105.177466][ T9562] The buggy address belongs to the page: [ 105.183096][ T9562] page:ffffea00028b4d80 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 [ 105.192195][ T9562] flags: 0xfffe0000000200(slab) [ 105.197027][ T9562] raw: 00fffe0000000200 ffffea00028bcbc8 ffffea0002915c88 ffff8880aa400e00 [ 105.205591][ T9562] raw: 0000000000000000 ffff8880a2d36000 0000000100000001 0000000000000000 [ 105.214153][ T9562] page dumped because: kasan: bad access detected [ 105.220540][ T9562] [ 105.222855][ T9562] Memory state around the buggy address: [ 105.228484][ T9562] ffff8880a2d35f00: 00 fc fc 00 00 00 00 00 fc fc 00 00 00 00 00 fc [ 105.236540][ T9562] ffff8880a2d35f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 105.244621][ T9562] >ffff8880a2d36000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 105.252723][ T9562] ^ [ 105.257064][ T9562] ffff8880a2d36080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 105.265214][ T9562] ffff8880a2d36100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 105.273255][ T9562] ================================================================== [ 105.281339][ T9562] Disabling lock debugging due to kernel taint [ 105.287468][ T9562] Kernel panic - not syncing: panic_on_warn set ... [ 105.294053][ T9562] CPU: 1 PID: 9562 Comm: syz-executor507 Tainted: G B 5.6.0-rc2-syzkaller #0 [ 105.304087][ T9562] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 105.314120][ T9562] Call Trace: [ 105.317399][ T9562] dump_stack+0x197/0x210 [ 105.321719][ T9562] panic+0x2e3/0x75c [ 105.325596][ T9562] ? add_taint.cold+0x16/0x16 [ 105.330266][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 105.335102][ T9562] ? trace_hardirqs_off+0x62/0x240 [ 105.340198][ T9562] ? trace_hardirqs_off+0x59/0x240 [ 105.345364][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 105.350241][ T9562] end_report+0x47/0x4f [ 105.354378][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 105.359245][ T9562] __kasan_report.cold+0xe/0x32 [ 105.364227][ T9562] ? get_work_pool_id+0x1c/0xe0 [ 105.369101][ T9562] kasan_report+0x12/0x20 [ 105.373413][ T9562] check_memory_region+0x134/0x1a0 [ 105.378529][ T9562] __kasan_check_read+0x11/0x20 [ 105.383365][ T9562] get_work_pool_id+0x1c/0xe0 [ 105.388025][ T9562] __cancel_work_timer+0xfa/0x540 [ 105.393031][ T9562] ? console_unlock+0x7b3/0xf00 [ 105.397928][ T9562] ? mod_delayed_work_on+0x200/0x200 [ 105.403641][ T9562] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 105.409342][ T9562] ? console_unlock+0x81e/0xf00 [ 105.414286][ T9562] cancel_work_sync+0x18/0x20 [ 105.418960][ T9562] tty_buffer_cancel_work+0x16/0x20 [ 105.424328][ T9562] release_tty+0x261/0x470 [ 105.428749][ T9562] tty_release_struct+0x3c/0x50 [ 105.433590][ T9562] tty_release+0xbcb/0xe90 [ 105.438000][ T9562] __fput+0x2ff/0x890 [ 105.441978][ T9562] ? do_tty_hangup+0x30/0x30 [ 105.446559][ T9562] ____fput+0x16/0x20 [ 105.450531][ T9562] task_work_run+0x145/0x1c0 [ 105.455109][ T9562] do_exit+0xba9/0x2f50 [ 105.459285][ T9562] ? mm_update_next_owner+0x7c0/0x7c0 [ 105.464658][ T9562] ? up_read+0x1cd/0x810 [ 105.468883][ T9562] ? down_read_non_owner+0x490/0x490 [ 105.474161][ T9562] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 105.479605][ T9562] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 105.485046][ T9562] do_group_exit+0x135/0x360 [ 105.489624][ T9562] __x64_sys_exit_group+0x44/0x50 [ 105.494636][ T9562] do_syscall_64+0xfa/0x790 [ 105.499126][ T9562] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 105.504996][ T9562] RIP: 0033:0x43ff38 [ 105.508879][ T9562] Code: Bad RIP value. [ 105.512995][ T9562] RSP: 002b:00007fff706d7d78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 105.521913][ T9562] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 105.529991][ T9562] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 105.538047][ T9562] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 105.546014][ T9562] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 105.553968][ T9562] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 105.563237][ T9562] Kernel Offset: disabled [ 105.567584][ T9562] Rebooting in 86400 seconds..