[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.15.203' (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 syzkaller login: [ 153.287313][ T7771] ================================================================== [ 153.295556][ T7771] BUG: KASAN: use-after-free in io_wq_worker_running+0xde/0x110 [ 153.303185][ T7771] Write of size 4 at addr ffff8882183db08c by task io_wqe_worker-0/7771 [ 153.311494][ T7771] [ 153.313822][ T7771] CPU: 0 PID: 7771 Comm: io_wqe_worker-0 Not tainted 5.9.0-rc4-syzkaller #0 [ 153.322532][ T7771] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 153.332601][ T7771] Call Trace: [ 153.335892][ T7771] dump_stack+0x198/0x1fd [ 153.340220][ T7771] ? io_wq_worker_running+0xde/0x110 [ 153.345548][ T7771] ? io_wq_worker_running+0xde/0x110 [ 153.350831][ T7771] print_address_description.constprop.0.cold+0xae/0x497 [ 153.357853][ T7771] ? io_wq_worker_running+0xde/0x110 [ 153.363137][ T7771] ? lockdep_hardirqs_off+0x96/0xd0 [ 153.368334][ T7771] ? vprintk_func+0x97/0x1a6 [ 153.372926][ T7771] ? io_wq_worker_running+0xde/0x110 [ 153.378208][ T7771] ? io_wq_worker_running+0xde/0x110 [ 153.383495][ T7771] kasan_report.cold+0x1f/0x37 [ 153.388260][ T7771] ? match_held_lock+0xd1/0x170 [ 153.393106][ T7771] ? io_wq_worker_running+0xde/0x110 [ 153.398391][ T7771] check_memory_region+0x13d/0x180 [ 153.403504][ T7771] io_wq_worker_running+0xde/0x110 [ 153.408615][ T7771] schedule_timeout+0x148/0x250 [ 153.413469][ T7771] ? usleep_range+0x170/0x170 [ 153.418147][ T7771] ? __next_timer_interrupt+0x210/0x210 [ 153.423709][ T7771] ? lockdep_hardirqs_on_prepare+0x354/0x530 [ 153.429715][ T7771] ? _raw_spin_unlock_irqrestore+0x6f/0x90 [ 153.435525][ T7771] ? lockdep_hardirqs_on+0x53/0x100 [ 153.440754][ T7771] io_wqe_worker+0x517/0x10e0 [ 153.445488][ T7771] ? io_worker_handle_work+0x13f0/0x13f0 [ 153.451126][ T7771] ? lockdep_hardirqs_on+0x53/0x100 [ 153.456323][ T7771] ? __kthread_parkme+0x13f/0x1e0 [ 153.461342][ T7771] ? io_worker_handle_work+0x13f0/0x13f0 [ 153.466972][ T7771] kthread+0x3b5/0x4a0 [ 153.471034][ T7771] ? __kthread_bind_mask+0xc0/0xc0 [ 153.476145][ T7771] ret_from_fork+0x1f/0x30 [ 153.480569][ T7771] [ 153.482893][ T7771] Allocated by task 7768: [ 153.487215][ T7771] kasan_save_stack+0x1b/0x40 [ 153.491885][ T7771] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 153.497513][ T7771] kmem_cache_alloc_node_trace+0x17b/0x3f0 [ 153.503311][ T7771] io_wq_create+0x57b/0xa10 [ 153.507808][ T7771] io_uring_setup+0x1836/0x28e0 [ 153.512653][ T7771] do_syscall_64+0x2d/0x70 [ 153.517070][ T7771] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 153.522945][ T7771] [ 153.525263][ T7771] Freed by task 21: [ 153.529065][ T7771] kasan_save_stack+0x1b/0x40 [ 153.533743][ T7771] kasan_set_track+0x1c/0x30 [ 153.538330][ T7771] kasan_set_free_info+0x1b/0x30 [ 153.543262][ T7771] __kasan_slab_free+0xd8/0x120 [ 153.548106][ T7771] kfree+0x10e/0x2b0 [ 153.552000][ T7771] io_wq_destroy+0x2af/0x460 [ 153.556593][ T7771] io_ring_exit_work+0x1e4/0x6d0 [ 153.561526][ T7771] process_one_work+0x94c/0x1670 [ 153.566458][ T7771] worker_thread+0x64c/0x1120 [ 153.571139][ T7771] kthread+0x3b5/0x4a0 [ 153.575205][ T7771] ret_from_fork+0x1f/0x30 [ 153.579608][ T7771] [ 153.581932][ T7771] The buggy address belongs to the object at ffff8882183db000 [ 153.581932][ T7771] which belongs to the cache kmalloc-1k of size 1024 [ 153.595977][ T7771] The buggy address is located 140 bytes inside of [ 153.595977][ T7771] 1024-byte region [ffff8882183db000, ffff8882183db400) [ 153.609318][ T7771] The buggy address belongs to the page: [ 153.614968][ T7771] page:000000009bada22b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2183db [ 153.625228][ T7771] flags: 0x57ffe0000000200(slab) [ 153.630174][ T7771] raw: 057ffe0000000200 ffffea0008604c48 ffffea00086a8648 ffff8880aa040700 [ 153.638755][ T7771] raw: 0000000000000000 ffff8882183db000 0000000100000002 0000000000000000 [ 153.647324][ T7771] page dumped because: kasan: bad access detected [ 153.653719][ T7771] [ 153.656037][ T7771] Memory state around the buggy address: [ 153.661681][ T7771] ffff8882183daf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 153.669734][ T7771] ffff8882183db000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 153.677787][ T7771] >ffff8882183db080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program [ 153.685834][ T7771] ^ [ 153.690157][ T7771] ffff8882183db100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 153.698212][ T7771] ffff8882183db180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 153.706273][ T7771] ================================================================== [ 153.714320][ T7771] Disabling lock debugging due to kernel taint executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 155.816784][ T7771] Kernel panic - not syncing: panic_on_warn set ... [ 155.823391][ T7771] CPU: 1 PID: 7771 Comm: io_wqe_worker-0 Tainted: G B 5.9.0-rc4-syzkaller #0 [ 155.833434][ T7771] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 155.843473][ T7771] Call Trace: [ 155.846755][ T7771] dump_stack+0x198/0x1fd [ 155.851076][ T7771] ? io_wq_manager+0x990/0x9a0 [ 155.855831][ T7771] panic+0x347/0x7c0 [ 155.859717][ T7771] ? __warn_printk+0xf3/0xf3 [ 155.864298][ T7771] ? preempt_schedule_common+0x59/0xc0 [ 155.869774][ T7771] ? io_wq_worker_running+0xde/0x110 [ 155.875055][ T7771] ? preempt_schedule_thunk+0x16/0x18 [ 155.880415][ T7771] ? trace_hardirqs_on+0x55/0x220 [ 155.885427][ T7771] ? io_wq_worker_running+0xde/0x110 [ 155.890695][ T7771] ? io_wq_worker_running+0xde/0x110 [ 155.895969][ T7771] end_report+0x4d/0x53 [ 155.900114][ T7771] kasan_report.cold+0xd/0x37 [ 155.904784][ T7771] ? match_held_lock+0xd1/0x170 [ 155.909622][ T7771] ? io_wq_worker_running+0xde/0x110 [ 155.914899][ T7771] check_memory_region+0x13d/0x180 [ 155.920010][ T7771] io_wq_worker_running+0xde/0x110 [ 155.925122][ T7771] schedule_timeout+0x148/0x250 [ 155.929970][ T7771] ? usleep_range+0x170/0x170 [ 155.934640][ T7771] ? __next_timer_interrupt+0x210/0x210 [ 155.940182][ T7771] ? lockdep_hardirqs_on_prepare+0x354/0x530 [ 155.946151][ T7771] ? _raw_spin_unlock_irqrestore+0x6f/0x90 [ 155.951946][ T7771] ? lockdep_hardirqs_on+0x53/0x100 [ 155.957134][ T7771] io_wqe_worker+0x517/0x10e0 [ 155.961805][ T7771] ? io_worker_handle_work+0x13f0/0x13f0 [ 155.967439][ T7771] ? lockdep_hardirqs_on+0x53/0x100 [ 155.972636][ T7771] ? __kthread_parkme+0x13f/0x1e0 [ 155.977661][ T7771] ? io_worker_handle_work+0x13f0/0x13f0 [ 155.983296][ T7771] kthread+0x3b5/0x4a0 [ 155.987368][ T7771] ? __kthread_bind_mask+0xc0/0xc0 [ 155.992481][ T7771] ret_from_fork+0x1f/0x30 [ 155.997904][ T7771] Kernel Offset: disabled [ 156.002213][ T7771] Rebooting in 86400 seconds..