[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.165' (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 syzkaller login: [ 545.309576][ T27] audit: type=1400 audit(1596566508.082:8): avc: denied { execmem } for pid=6842 comm="syz-executor154" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 545.497950][ T2575] ================================================================== [ 545.506354][ T2575] BUG: KASAN: use-after-free in l2cap_chan_close+0x564/0xb10 [ 545.513739][ T2575] Read of size 1 at addr ffff88809ffd5020 by task kworker/0:2/2575 [ 545.521623][ T2575] [ 545.523970][ T2575] CPU: 0 PID: 2575 Comm: kworker/0:2 Not tainted 5.8.0-syzkaller #0 [ 545.531940][ T2575] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 545.542090][ T2575] Workqueue: events do_enable_set [ 545.547308][ T2575] Call Trace: [ 545.550738][ T2575] dump_stack+0x18f/0x20d [ 545.555105][ T2575] ? l2cap_chan_close+0x564/0xb10 [ 545.560139][ T2575] ? l2cap_chan_close+0x564/0xb10 [ 545.565402][ T2575] print_address_description.constprop.0.cold+0xae/0x436 [ 545.572688][ T2575] ? mark_lock+0xbc/0x1710 [ 545.577216][ T2575] ? vprintk_func+0x97/0x1a6 [ 545.582191][ T2575] ? l2cap_chan_close+0x564/0xb10 [ 545.587235][ T2575] kasan_report.cold+0x1f/0x37 [ 545.592008][ T2575] ? l2cap_chan_close+0x564/0xb10 [ 545.597036][ T2575] l2cap_chan_close+0x564/0xb10 [ 545.601912][ T2575] ? l2cap_retransmit_all+0x760/0x760 [ 545.607302][ T2575] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 545.613311][ T2575] do_enable_set+0x4ed/0x980 [ 545.617919][ T2575] ? chan_recv_cb+0xa10/0xa10 [ 545.622792][ T2575] ? _raw_spin_unlock_irq+0x1f/0x80 [ 545.628004][ T2575] ? _raw_spin_unlock_irq+0x1f/0x80 [ 545.633254][ T2575] ? lock_is_held_type+0xbb/0xf0 [ 545.638317][ T2575] process_one_work+0x94c/0x1670 [ 545.643273][ T2575] ? lock_release+0x8e0/0x8e0 [ 545.647958][ T2575] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 545.653339][ T2575] ? rwlock_bug.part.0+0x90/0x90 [ 545.658290][ T2575] worker_thread+0x64c/0x1120 [ 545.663028][ T2575] ? __kthread_parkme+0x13f/0x1e0 [ 545.668053][ T2575] ? process_one_work+0x1670/0x1670 [ 545.673246][ T2575] kthread+0x3b5/0x4a0 [ 545.677310][ T2575] ? __kthread_bind_mask+0xc0/0xc0 [ 545.682434][ T2575] ? __kthread_bind_mask+0xc0/0xc0 [ 545.687605][ T2575] ret_from_fork+0x1f/0x30 [ 545.692022][ T2575] [ 545.694373][ T2575] Allocated by task 2575: [ 545.698699][ T2575] save_stack+0x1b/0x40 [ 545.702844][ T2575] __kasan_kmalloc.constprop.0+0xc2/0xd0 [ 545.708502][ T2575] kmem_cache_alloc_trace+0x14f/0x2d0 [ 545.713878][ T2575] l2cap_chan_create+0x40/0x3a0 [ 545.718748][ T2575] do_enable_set+0x52f/0x980 [ 545.723333][ T2575] process_one_work+0x94c/0x1670 [ 545.728274][ T2575] worker_thread+0x64c/0x1120 [ 545.732947][ T2575] kthread+0x3b5/0x4a0 [ 545.737009][ T2575] ret_from_fork+0x1f/0x30 [ 545.741408][ T2575] [ 545.743741][ T2575] Freed by task 2861: [ 545.747717][ T2575] save_stack+0x1b/0x40 [ 545.751864][ T2575] __kasan_slab_free+0xf5/0x140 [ 545.756702][ T2575] kfree+0x103/0x2c0 [ 545.760597][ T2575] l2cap_chan_put+0x1b2/0x230 [ 545.765279][ T2575] do_enable_set+0x4f9/0x980 [ 545.769871][ T2575] process_one_work+0x94c/0x1670 [ 545.774800][ T2575] worker_thread+0x64c/0x1120 [ 545.779476][ T2575] kthread+0x3b5/0x4a0 [ 545.783561][ T2575] ret_from_fork+0x1f/0x30 [ 545.787973][ T2575] [ 545.790367][ T2575] The buggy address belongs to the object at ffff88809ffd5000 [ 545.790367][ T2575] which belongs to the cache kmalloc-2k of size 2048 [ 545.804433][ T2575] The buggy address is located 32 bytes inside of [ 545.804433][ T2575] 2048-byte region [ffff88809ffd5000, ffff88809ffd5800) [ 545.817693][ T2575] The buggy address belongs to the page: [ 545.823411][ T2575] page:ffffea00027ff540 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 [ 545.832508][ T2575] flags: 0xfffe0000000200(slab) [ 545.837356][ T2575] raw: 00fffe0000000200 ffffea00023cd108 ffffea00023b23c8 ffff8880aa000e00 [ 545.845939][ T2575] raw: 0000000000000000 ffff88809ffd5000 0000000100000001 0000000000000000 [ 545.854508][ T2575] page dumped because: kasan: bad access detected [ 545.860906][ T2575] [ 545.863221][ T2575] Memory state around the buggy address: [ 545.868853][ T2575] ffff88809ffd4f00: fb fb fb fb fb fb fb fb fc fc fc fc fb fb fb fb [ 545.876909][ T2575] ffff88809ffd4f80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc [ 545.884961][ T2575] >ffff88809ffd5000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 545.893006][ T2575] ^ executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 545.898106][ T2575] ffff88809ffd5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 545.906159][ T2575] ffff88809ffd5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 545.914205][ T2575] ================================================================== [ 545.922285][ T2575] 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 546.141495][ T2575] Kernel panic - not syncing: panic_on_warn set ... [ 546.148127][ T2575] CPU: 0 PID: 2575 Comm: kworker/0:2 Tainted: G B 5.8.0-syzkaller #0 [ 546.157484][ T2575] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 546.167547][ T2575] Workqueue: events do_enable_set [ 546.172562][ T2575] Call Trace: [ 546.175858][ T2575] dump_stack+0x18f/0x20d [ 546.180191][ T2575] ? l2cap_chan_close+0x480/0xb10 [ 546.185331][ T2575] panic+0x2e3/0x75c [ 546.189231][ T2575] ? __warn_printk+0xf3/0xf3 [ 546.193838][ T2575] ? preempt_schedule_common+0x59/0xc0 [ 546.199296][ T2575] ? l2cap_chan_close+0x564/0xb10 [ 546.204324][ T2575] ? preempt_schedule_thunk+0x16/0x18 [ 546.209790][ T2575] ? trace_hardirqs_on+0x55/0x220 [ 546.214824][ T2575] ? l2cap_chan_close+0x564/0xb10 [ 546.219862][ T2575] ? l2cap_chan_close+0x564/0xb10 [ 546.224891][ T2575] end_report+0x4d/0x53 [ 546.229068][ T2575] kasan_report.cold+0xd/0x37 [ 546.233746][ T2575] ? l2cap_chan_close+0x564/0xb10 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 546.238774][ T2575] l2cap_chan_close+0x564/0xb10 [ 546.243625][ T2575] ? l2cap_retransmit_all+0x760/0x760 [ 546.248999][ T2575] ? lockdep_hardirqs_on_prepare+0x530/0x530 [ 546.254981][ T2575] do_enable_set+0x4ed/0x980 [ 546.259573][ T2575] ? chan_recv_cb+0xa10/0xa10 [ 546.264249][ T2575] ? _raw_spin_unlock_irq+0x1f/0x80 [ 546.269445][ T2575] ? _raw_spin_unlock_irq+0x1f/0x80 [ 546.274642][ T2575] ? lock_is_held_type+0xbb/0xf0 [ 546.279580][ T2575] process_one_work+0x94c/0x1670 [ 546.284521][ T2575] ? lock_release+0x8e0/0x8e0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 546.289198][ T2575] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 546.294569][ T2575] ? rwlock_bug.part.0+0x90/0x90 [ 546.299512][ T2575] worker_thread+0x64c/0x1120 [ 546.304194][ T2575] ? __kthread_parkme+0x13f/0x1e0 [ 546.309229][ T2575] ? process_one_work+0x1670/0x1670 [ 546.314460][ T2575] kthread+0x3b5/0x4a0 [ 546.318528][ T2575] ? __kthread_bind_mask+0xc0/0xc0 [ 546.323638][ T2575] ? __kthread_bind_mask+0xc0/0xc0 [ 546.328752][ T2575] ret_from_fork+0x1f/0x30 [ 546.334176][ T2575] Kernel Offset: disabled [ 546.338490][ T2575] Rebooting in 86400 seconds..