[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 69.257335][ T27] audit: type=1800 audit(1576872891.760:25): pid=9108 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 69.277494][ T27] audit: type=1800 audit(1576872891.760:26): pid=9108 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 69.334619][ T27] audit: type=1800 audit(1576872891.760:27): pid=9108 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 '10.128.1.22' (ECDSA) to the list of known hosts. syzkaller login: [ 96.885513][ T9260] IPVS: ftp: loaded support on port[0] = 21 [ 96.945001][ T9260] chnl_net:caif_netlink_parms(): no params data found [ 96.974643][ T9260] bridge0: port 1(bridge_slave_0) entered blocking state [ 96.982127][ T9260] bridge0: port 1(bridge_slave_0) entered disabled state [ 96.989915][ T9260] device bridge_slave_0 entered promiscuous mode [ 96.998955][ T9260] bridge0: port 2(bridge_slave_1) entered blocking state [ 97.006173][ T9260] bridge0: port 2(bridge_slave_1) entered disabled state [ 97.014340][ T9260] device bridge_slave_1 entered promiscuous mode [ 97.031831][ T9260] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link [ 97.043522][ T9260] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link [ 97.062666][ T9260] team0: Port device team_slave_0 added [ 97.070058][ T9260] team0: Port device team_slave_1 added [ 97.154185][ T9260] device hsr_slave_0 entered promiscuous mode [ 97.223421][ T9260] device hsr_slave_1 entered promiscuous mode [ 97.286421][ T9260] netdevsim netdevsim0 netdevsim0: renamed from eth0 [ 97.345359][ T9260] netdevsim netdevsim0 netdevsim1: renamed from eth1 [ 97.404684][ T9260] netdevsim netdevsim0 netdevsim2: renamed from eth2 [ 97.444583][ T9260] netdevsim netdevsim0 netdevsim3: renamed from eth3 [ 97.504317][ T9260] bridge0: port 2(bridge_slave_1) entered blocking state [ 97.511479][ T9260] bridge0: port 2(bridge_slave_1) entered forwarding state [ 97.519358][ T9260] bridge0: port 1(bridge_slave_0) entered blocking state [ 97.526483][ T9260] bridge0: port 1(bridge_slave_0) entered forwarding state [ 97.566302][ T9260] 8021q: adding VLAN 0 to HW filter on device bond0 [ 97.579049][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 97.599863][ T3024] bridge0: port 1(bridge_slave_0) entered disabled state [ 97.618558][ T3024] bridge0: port 2(bridge_slave_1) entered disabled state [ 97.627720][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 97.640308][ T9260] 8021q: adding VLAN 0 to HW filter on device team0 [ 97.651696][ T17] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 97.660708][ T17] bridge0: port 1(bridge_slave_0) entered blocking state [ 97.667851][ T17] bridge0: port 1(bridge_slave_0) entered forwarding state [ 97.693853][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 97.703050][ T3024] bridge0: port 2(bridge_slave_1) entered blocking state [ 97.710126][ T3024] bridge0: port 2(bridge_slave_1) entered forwarding state [ 97.718363][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 97.727386][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 97.736443][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready [ 97.745264][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready [ 97.756758][ T2797] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready [ 97.768440][ T9260] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready [ 97.786564][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready [ 97.795059][ T3024] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready [ 97.809227][ T9260] 8021q: adding VLAN 0 to HW filter on device batadv0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 102.253104][ T2797] ================================================================== [ 102.261344][ T2797] BUG: KASAN: use-after-free in io_wq_flush+0x1f7/0x210 [ 102.268268][ T2797] Read of size 8 at addr ffff88809ea14b00 by task kworker/1:2/2797 [ 102.276180][ T2797] [ 102.278546][ T2797] CPU: 1 PID: 2797 Comm: kworker/1:2 Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 [ 102.288073][ T2797] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 102.298122][ T2797] Workqueue: events io_ring_file_ref_switch [ 102.303997][ T2797] Call Trace: [ 102.307272][ T2797] dump_stack+0x197/0x210 [ 102.311601][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.316197][ T2797] print_address_description.constprop.0.cold+0xd4/0x30b [ 102.323210][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.327789][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.332371][ T2797] __kasan_report.cold+0x1b/0x41 [ 102.337556][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.342146][ T2797] kasan_report+0x12/0x20 [ 102.346464][ T2797] __asan_report_load8_noabort+0x14/0x20 [ 102.352107][ T2797] io_wq_flush+0x1f7/0x210 [ 102.356541][ T2797] ? io_wq_cancel_work+0x600/0x600 [ 102.361650][ T2797] ? unix_notinflight+0x131/0x2e0 [ 102.366749][ T2797] ? io_work_cancel+0x1a0/0x1a0 [ 102.371634][ T2797] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 102.377786][ T2797] ? io_ring_file_ref_switch+0x68a/0xac0 [ 102.383463][ T2797] io_destruct_skb+0x8e/0xc0 [ 102.388095][ T2797] ? io_openat_prep+0x3c0/0x3c0 [ 102.392943][ T2797] skb_release_head_state+0xeb/0x260 [ 102.398214][ T2797] skb_release_all+0x16/0x60 [ 102.402797][ T2797] kfree_skb+0x101/0x420 [ 102.407028][ T2797] io_ring_file_ref_switch+0x68a/0xac0 [ 102.412487][ T2797] ? io_get_work+0xb0/0xb0 [ 102.416906][ T2797] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 102.422435][ T2797] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 102.428399][ T2797] ? trace_hardirqs_on+0x67/0x240 [ 102.433417][ T2797] process_one_work+0x9af/0x1740 [ 102.438352][ T2797] ? pwq_dec_nr_in_flight+0x320/0x320 [ 102.443703][ T2797] ? lock_acquire+0x190/0x410 [ 102.448369][ T2797] worker_thread+0x98/0xe40 [ 102.452874][ T2797] ? trace_hardirqs_on+0x67/0x240 [ 102.457885][ T2797] kthread+0x361/0x430 [ 102.461941][ T2797] ? process_one_work+0x1740/0x1740 [ 102.467118][ T2797] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 102.472856][ T2797] ret_from_fork+0x24/0x30 [ 102.477258][ T2797] [ 102.479567][ T2797] Allocated by task 9381: [ 102.483890][ T2797] save_stack+0x23/0x90 [ 102.488042][ T2797] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 102.493670][ T2797] kasan_kmalloc+0x9/0x10 [ 102.497994][ T2797] kmem_cache_alloc_trace+0x158/0x790 [ 102.503375][ T2797] io_wq_create+0x52/0xa40 [ 102.507786][ T2797] io_uring_setup+0xf4a/0x2080 [ 102.512548][ T2797] __x64_sys_io_uring_setup+0x54/0x80 [ 102.517925][ T2797] do_syscall_64+0xfa/0x790 [ 102.522434][ T2797] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 102.528303][ T2797] [ 102.530630][ T2797] Freed by task 9381: [ 102.534609][ T2797] save_stack+0x23/0x90 [ 102.538745][ T2797] __kasan_slab_free+0x102/0x150 [ 102.543669][ T2797] kasan_slab_free+0xe/0x10 [ 102.548176][ T2797] kfree+0x10a/0x2c0 [ 102.552084][ T2797] io_wq_destroy+0x2ce/0x3c0 [ 102.556654][ T2797] io_finish_async+0x128/0x1b0 [ 102.561400][ T2797] io_ring_ctx_wait_and_kill+0x330/0x9a0 [ 102.567035][ T2797] io_uring_release+0x42/0x50 [ 102.571730][ T2797] __fput+0x2ff/0x890 [ 102.575694][ T2797] ____fput+0x16/0x20 [ 102.579658][ T2797] task_work_run+0x145/0x1c0 [ 102.584233][ T2797] exit_to_usermode_loop+0x316/0x380 [ 102.589515][ T2797] do_syscall_64+0x676/0x790 [ 102.594090][ T2797] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 102.599955][ T2797] [ 102.602276][ T2797] The buggy address belongs to the object at ffff88809ea14b00 [ 102.602276][ T2797] which belongs to the cache kmalloc-192 of size 192 [ 102.616334][ T2797] The buggy address is located 0 bytes inside of [ 102.616334][ T2797] 192-byte region [ffff88809ea14b00, ffff88809ea14bc0) [ 102.629422][ T2797] The buggy address belongs to the page: [ 102.635063][ T2797] page:ffffea00027a8500 refcount:1 mapcount:0 mapping:ffff8880aa400000 index:0x0 [ 102.644151][ T2797] raw: 00fffe0000000200 ffffea00027a8148 ffffea00027a8f08 ffff8880aa400000 [ 102.652730][ T2797] raw: 0000000000000000 ffff88809ea14000 0000000100000010 0000000000000000 [ 102.661298][ T2797] page dumped because: kasan: bad access detected [ 102.667742][ T2797] [ 102.670056][ T2797] Memory state around the buggy address: [ 102.675674][ T2797] ffff88809ea14a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 102.683720][ T2797] ffff88809ea14a80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc [ 102.691764][ T2797] >ffff88809ea14b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 102.699829][ T2797] ^ [ 102.703883][ T2797] ffff88809ea14b80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 102.711946][ T2797] ffff88809ea14c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 102.719997][ T2797] ================================================================== [ 102.728044][ T2797] Disabling lock debugging due to kernel taint [ 102.735304][ T2797] Kernel panic - not syncing: panic_on_warn set ... [ 102.741974][ T2797] CPU: 1 PID: 2797 Comm: kworker/1:2 Tainted: G B 5.5.0-rc2-next-20191220-syzkaller #0 [ 102.752943][ T2797] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 102.763047][ T2797] Workqueue: events io_ring_file_ref_switch [ 102.768934][ T2797] Call Trace: [ 102.772222][ T2797] dump_stack+0x197/0x210 [ 102.776565][ T2797] panic+0x2e3/0x75c [ 102.780492][ T2797] ? add_taint.cold+0x16/0x16 [ 102.785167][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.789797][ T2797] ? preempt_schedule+0x4b/0x60 [ 102.794645][ T2797] ? ___preempt_schedule+0x16/0x18 [ 102.799764][ T2797] ? trace_hardirqs_on+0x5e/0x240 [ 102.804786][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.809370][ T2797] end_report+0x47/0x4f [ 102.813514][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.818103][ T2797] __kasan_report.cold+0xe/0x41 [ 102.822962][ T2797] ? io_wq_flush+0x1f7/0x210 [ 102.827588][ T2797] kasan_report+0x12/0x20 [ 102.831911][ T2797] __asan_report_load8_noabort+0x14/0x20 [ 102.837583][ T2797] io_wq_flush+0x1f7/0x210 [ 102.842029][ T2797] ? io_wq_cancel_work+0x600/0x600 [ 102.847189][ T2797] ? unix_notinflight+0x131/0x2e0 [ 102.852198][ T2797] ? io_work_cancel+0x1a0/0x1a0 [ 102.857054][ T2797] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 102.863203][ T2797] ? io_ring_file_ref_switch+0x68a/0xac0 [ 102.868813][ T2797] io_destruct_skb+0x8e/0xc0 [ 102.873390][ T2797] ? io_openat_prep+0x3c0/0x3c0 [ 102.878235][ T2797] skb_release_head_state+0xeb/0x260 [ 102.883500][ T2797] skb_release_all+0x16/0x60 [ 102.888128][ T2797] kfree_skb+0x101/0x420 [ 102.892413][ T2797] io_ring_file_ref_switch+0x68a/0xac0 [ 102.897880][ T2797] ? io_get_work+0xb0/0xb0 [ 102.902294][ T2797] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 102.907830][ T2797] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 102.913806][ T2797] ? trace_hardirqs_on+0x67/0x240 [ 102.918838][ T2797] process_one_work+0x9af/0x1740 [ 102.923882][ T2797] ? pwq_dec_nr_in_flight+0x320/0x320 [ 102.929241][ T2797] ? lock_acquire+0x190/0x410 [ 102.933973][ T2797] worker_thread+0x98/0xe40 [ 102.938505][ T2797] ? trace_hardirqs_on+0x67/0x240 [ 102.943583][ T2797] kthread+0x361/0x430 [ 102.947634][ T2797] ? process_one_work+0x1740/0x1740 [ 102.952855][ T2797] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 102.958567][ T2797] ret_from_fork+0x24/0x30 [ 102.964319][ T2797] Kernel Offset: disabled [ 102.968645][ T2797] Rebooting in 86400 seconds..