[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.43' (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: [ 538.526144] audit: type=1400 audit(1596735869.388:8): avc: denied { execmem } for pid=6465 comm="syz-executor257" 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing 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executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 539.176758] ================================================================== [ 539.187082] BUG: KASAN: use-after-free in l2cap_chan_close+0x58b/0x820 [ 539.199044] Read of size 1 at addr ffff8880a47d71a0 by task kworker/0:3/6151 [ 539.209255] [ 539.211156] CPU: 0 PID: 6151 Comm: kworker/0:3 Not tainted 4.19.137-syzkaller #0 [ 539.221461] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 539.234287] Workqueue: events do_enable_set [ 539.238690] Call Trace: [ 539.241365] dump_stack+0x1fc/0x2fe [ 539.246230] print_address_description.cold+0x54/0x219 [ 539.251766] kasan_report_error.cold+0x8a/0x1c7 [ 539.257743] ? l2cap_chan_close+0x58b/0x820 [ 539.262060] __asan_report_load1_noabort+0x88/0x90 [ 539.267597] ? l2cap_chan_close+0x58b/0x820 [ 539.271963] l2cap_chan_close+0x58b/0x820 [ 539.276107] ? __set_monitor_timer+0x130/0x130 [ 539.280863] ? lock_downgrade+0x720/0x720 [ 539.285984] ? lock_acquire+0x170/0x3c0 [ 539.290008] ? debug_object_deactivate+0xfc/0x2e0 [ 539.295288] ? trace_hardirqs_off+0x64/0x200 [ 539.299785] do_enable_set+0x4e3/0x975 [ 539.303763] ? process_one_work+0x77b/0x1570 [ 539.308430] ? chan_recv_cb+0xa70/0xa70 [ 539.312492] ? check_preemption_disabled+0x41/0x280 [ 539.317760] process_one_work+0x864/0x1570 [ 539.322608] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 539.327372] worker_thread+0x64c/0x1130 [ 539.331442] ? __kthread_parkme+0xfd/0x1b0 [ 539.335680] ? process_one_work+0x1570/0x1570 [ 539.340174] kthread+0x30b/0x410 [ 539.343538] ? kthread_park+0x180/0x180 [ 539.347659] ret_from_fork+0x24/0x30 [ 539.351376] [ 539.352995] Allocated by task 2763: [ 539.356650] kmem_cache_alloc_trace+0x12f/0x380 [ 539.361313] l2cap_chan_create+0x40/0x380 [ 539.365470] do_enable_set+0x525/0x975 [ 539.371392] process_one_work+0x864/0x1570 [ 539.376760] worker_thread+0x64c/0x1130 [ 539.380903] kthread+0x30b/0x410 [ 539.384353] ret_from_fork+0x24/0x30 [ 539.388056] [ 539.389672] Freed by task 2763: [ 539.392946] kfree+0xcc/0x210 [ 539.396044] l2cap_chan_put+0x16b/0x1c0 [ 539.400810] do_enable_set+0x4ef/0x975 [ 539.404949] process_one_work+0x864/0x1570 [ 539.409837] worker_thread+0x64c/0x1130 [ 539.413808] kthread+0x30b/0x410 [ 539.417259] ret_from_fork+0x24/0x30 [ 539.421751] [ 539.423373] The buggy address belongs to the object at ffff8880a47d7180 [ 539.423373] which belongs to the cache kmalloc-2048 of size 2048 [ 539.436733] The buggy address is located 32 bytes inside of [ 539.436733] 2048-byte region [ffff8880a47d7180, ffff8880a47d7980) [ 539.450209] The buggy address belongs to the page: [ 539.455397] page:ffffea000291f580 count:1 mapcount:0 mapping:ffff88812c39cc40 index:0x0 compound_mapcount: 0 [ 539.468602] flags: 0xfffe0000008100(slab|head) [ 539.473205] raw: 00fffe0000008100 ffffea0002903f08 ffffea000290ab88 ffff88812c39cc40 [ 539.483633] raw: 0000000000000000 ffff8880a47d6080 0000000100000003 0000000000000000 [ 539.492117] page dumped because: kasan: bad access detected [ 539.497923] [ 539.500096] Memory state around the buggy address: [ 539.505229] ffff8880a47d7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 539.514721] ffff8880a47d7100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 539.522780] >ffff8880a47d7180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 539.530392] ^ [ 539.538880] ffff8880a47d7200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 539.546320] ffff8880a47d7280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 539.553683] ================================================================== [ 539.561033] 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 [ 539.611361] Kernel panic - not syncing: panic_on_warn set ... [ 539.611361] [ 539.619396] CPU: 0 PID: 6151 Comm: kworker/0:3 Tainted: G B 4.19.137-syzkaller #0 [ 539.628314] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 539.637709] Workqueue: events do_enable_set [ 539.642052] Call Trace: [ 539.644644] dump_stack+0x1fc/0x2fe [ 539.648276] panic+0x26a/0x50e [ 539.651470] ? __warn_printk+0xf3/0xf3 [ 539.655362] ? preempt_schedule_common+0x45/0xc0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 539.660137] ? ___preempt_schedule+0x16/0x18 [ 539.664557] ? trace_hardirqs_on+0x55/0x210 [ 539.668889] kasan_end_report+0x43/0x49 [ 539.672956] kasan_report_error.cold+0xa7/0x1c7 [ 539.677632] ? l2cap_chan_close+0x58b/0x820 [ 539.682227] __asan_report_load1_noabort+0x88/0x90 [ 539.687172] ? l2cap_chan_close+0x58b/0x820 [ 539.691508] l2cap_chan_close+0x58b/0x820 [ 539.695668] ? __set_monitor_timer+0x130/0x130 [ 539.700267] ? lock_downgrade+0x720/0x720 [ 539.704424] ? lock_acquire+0x170/0x3c0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 539.708439] ? debug_object_deactivate+0xfc/0x2e0 [ 539.713289] ? trace_hardirqs_off+0x64/0x200 [ 539.717710] do_enable_set+0x4e3/0x975 [ 539.721605] ? process_one_work+0x77b/0x1570 [ 539.726021] ? chan_recv_cb+0xa70/0xa70 [ 539.730008] ? check_preemption_disabled+0x41/0x280 [ 539.735034] process_one_work+0x864/0x1570 [ 539.739279] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 539.743956] worker_thread+0x64c/0x1130 [ 539.747961] ? __kthread_parkme+0xfd/0x1b0 [ 539.752197] ? process_one_work+0x1570/0x1570 [ 539.756785] kthread+0x30b/0x410 executing program executing program [ 539.760161] ? kthread_park+0x180/0x180 [ 539.764144] ret_from_fork+0x24/0x30 [ 539.768838] Kernel Offset: disabled [ 539.772465] Rebooting in 86400 seconds..