[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started getty on tty2-tty6 if dbus and logind are not available. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.145' (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 syzkaller login: [ 733.592370][T11054] ================================================================== [ 733.600642][T11054] BUG: KASAN: use-after-free in __lock_acquire+0x92/0x2ae0 [ 733.607825][T11054] Read of size 8 at addr ffff88821ae5f818 by task io_wqe_worker-0/11054 [ 733.616122][T11054] [ 733.618439][T11054] CPU: 1 PID: 11054 Comm: io_wqe_worker-0 Not tainted 5.9.0-rc6-syzkaller #0 [ 733.627174][T11054] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 733.637212][T11054] Call Trace: [ 733.640556][T11054] dump_stack+0x1d6/0x29e [ 733.644950][T11054] print_address_description+0x66/0x620 [ 733.650510][T11054] ? printk+0x62/0x83 [ 733.654496][T11054] ? vprintk_emit+0x2f0/0x370 [ 733.659159][T11054] kasan_report+0x132/0x1d0 [ 733.663647][T11054] ? __lock_acquire+0x92/0x2ae0 [ 733.668489][T11054] __lock_acquire+0x92/0x2ae0 [ 733.673202][T11054] ? __free_object+0x1ff/0xcc0 [ 733.678030][T11054] ? lockdep_hardirqs_on+0x79/0x100 [ 733.683232][T11054] ? lock_is_held_type+0xb3/0xe0 [ 733.688208][T11054] ? rcu_read_lock_sched_held+0x2f/0xa0 [ 733.693740][T11054] ? debug_object_free+0x395/0x450 [ 733.698839][T11054] ? lock_is_held_type+0xb3/0xe0 [ 733.703776][T11054] ? rcu_read_lock_sched_held+0x2f/0xa0 [ 733.709334][T11054] lock_acquire+0x148/0x720 [ 733.713871][T11054] ? io_wqe_worker+0x756/0x810 [ 733.718624][T11054] ? check_preemption_disabled+0x51/0x140 [ 733.724367][T11054] ? _raw_spin_lock_irq+0x80/0xc0 [ 733.729377][T11054] _raw_spin_lock_irq+0xa6/0xc0 [ 733.734211][T11054] ? io_wqe_worker+0x756/0x810 [ 733.738961][T11054] io_wqe_worker+0x756/0x810 [ 733.743587][T11054] kthread+0x37e/0x3a0 [ 733.747649][T11054] ? create_io_worker+0x5f0/0x5f0 [ 733.752659][T11054] ? kthread_blkcg+0xd0/0xd0 [ 733.757295][T11054] ret_from_fork+0x1f/0x30 [ 733.761702][T11054] [ 733.764030][T11054] Allocated by task 11048: [ 733.768461][T11054] __kasan_kmalloc+0x100/0x130 [ 733.773216][T11054] kmem_cache_alloc_node_trace+0x1f7/0x2a0 [ 733.779000][T11054] io_wq_create+0x295/0x880 [ 733.783518][T11054] __se_sys_io_uring_setup+0x18ed/0x2a00 [ 733.789136][T11054] do_syscall_64+0x31/0x70 [ 733.793550][T11054] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 733.799416][T11054] [ 733.801743][T11054] Freed by task 128: [ 733.805618][T11054] kasan_set_track+0x3d/0x70 [ 733.810191][T11054] kasan_set_free_info+0x17/0x30 [ 733.815133][T11054] __kasan_slab_free+0xdd/0x110 [ 733.819966][T11054] kfree+0x113/0x200 [ 733.823848][T11054] io_wq_destroy+0x470/0x510 [ 733.828417][T11054] io_ring_exit_work+0x195/0x520 [ 733.833371][T11054] process_one_work+0x789/0xfc0 [ 733.838207][T11054] worker_thread+0xaa4/0x1460 [ 733.842863][T11054] kthread+0x37e/0x3a0 [ 733.846944][T11054] ret_from_fork+0x1f/0x30 [ 733.851335][T11054] [ 733.853665][T11054] The buggy address belongs to the object at ffff88821ae5f800 [ 733.853665][T11054] which belongs to the cache kmalloc-1k of size 1024 [ 733.867702][T11054] The buggy address is located 24 bytes inside of [ 733.867702][T11054] 1024-byte region [ffff88821ae5f800, ffff88821ae5fc00) [ 733.880947][T11054] The buggy address belongs to the page: [ 733.886568][T11054] page:000000008e41b1c2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21ae5f [ 733.896784][T11054] flags: 0x57ffe0000000200(slab) [ 733.901710][T11054] raw: 057ffe0000000200 ffffea00086a10c8 ffffea00085d1848 ffff8880aa440700 [ 733.910280][T11054] raw: 0000000000000000 ffff88821ae5f000 0000000100000002 0000000000000000 [ 733.918842][T11054] page dumped because: kasan: bad access detected [ 733.925261][T11054] [ 733.927573][T11054] Memory state around the buggy address: [ 733.933187][T11054] ffff88821ae5f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 733.941233][T11054] ffff88821ae5f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 733.949275][T11054] >ffff88821ae5f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 733.957314][T11054] ^ [ 733.962143][T11054] ffff88821ae5f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 733.970186][T11054] ffff88821ae5f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 733.978225][T11054] ================================================================== [ 733.986264][T11054] Disabling lock debugging due to kernel taint [ 733.992395][T11054] Kernel panic - not syncing: panic_on_warn set ... [ 733.998965][T11054] CPU: 1 PID: 11054 Comm: io_wqe_worker-0 Tainted: G B 5.9.0-rc6-syzkaller #0 [ 734.009097][T11054] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 734.019133][T11054] Call Trace: [ 734.022410][T11054] dump_stack+0x1d6/0x29e [ 734.026829][T11054] panic+0x2c0/0x800 [ 734.030721][T11054] kasan_report+0x1c9/0x1d0 [ 734.035225][T11054] ? __lock_acquire+0x92/0x2ae0 [ 734.040061][T11054] __lock_acquire+0x92/0x2ae0 [ 734.044739][T11054] ? __free_object+0x1ff/0xcc0 [ 734.049499][T11054] ? lockdep_hardirqs_on+0x79/0x100 [ 734.054700][T11054] ? lock_is_held_type+0xb3/0xe0 [ 734.059624][T11054] ? rcu_read_lock_sched_held+0x2f/0xa0 [ 734.065169][T11054] ? debug_object_free+0x395/0x450 [ 734.070264][T11054] ? lock_is_held_type+0xb3/0xe0 [ 734.075184][T11054] ? rcu_read_lock_sched_held+0x2f/0xa0 [ 734.080712][T11054] lock_acquire+0x148/0x720 [ 734.085201][T11054] ? io_wqe_worker+0x756/0x810 [ 734.089979][T11054] ? check_preemption_disabled+0x51/0x140 [ 734.095684][T11054] ? _raw_spin_lock_irq+0x80/0xc0 [ 734.100706][T11054] _raw_spin_lock_irq+0xa6/0xc0 [ 734.105555][T11054] ? io_wqe_worker+0x756/0x810 [ 734.110335][T11054] io_wqe_worker+0x756/0x810 [ 734.114933][T11054] kthread+0x37e/0x3a0 [ 734.118989][T11054] ? create_io_worker+0x5f0/0x5f0 [ 734.123999][T11054] ? kthread_blkcg+0xd0/0xd0 [ 734.128575][T11054] ret_from_fork+0x1f/0x30 [ 734.133954][T11054] Kernel Offset: disabled [ 734.138261][T11054] Rebooting in 86400 seconds..