[ OK ] Started Getty on tty1. [ OK ] Started Getty on tty3. [ OK ] Started Serial Getty on ttyS0. [ 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. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.182' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 29.480239] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.544256] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.592619] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.642491] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.691984] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.742354] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.802151] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.852494] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.901882] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program [ 29.951840] netlink: 4 bytes leftover after parsing attributes in process `syz-executor846'. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 31.011892] ================================================================== [ 31.019381] BUG: KASAN: use-after-free in ex_handler_refcount+0x164/0x1a0 [ 31.026295] Write of size 4 at addr ffff8880b310b3d8 by task systemd-udevd/8145 [ 31.033744] [ 31.035356] CPU: 1 PID: 8145 Comm: systemd-udevd Not tainted 4.14.229-syzkaller #0 [ 31.043124] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.052457] Call Trace: [ 31.055029] dump_stack+0x1b2/0x281 [ 31.058639] print_address_description.cold+0x54/0x1d3 [ 31.063896] kasan_report_error.cold+0x8a/0x191 [ 31.068545] ? ex_handler_refcount+0x164/0x1a0 [ 31.073122] __asan_report_store4_noabort+0x68/0x70 [ 31.078128] ? ex_handler_refcount+0x164/0x1a0 [ 31.082706] ex_handler_refcount+0x164/0x1a0 [ 31.087093] ? ex_handler_clear_fs+0xb0/0xb0 [ 31.091489] fixup_exception+0x8a/0xd0 [ 31.095386] do_trap+0x61/0x250 [ 31.098657] ? do_error_trap+0x1d0/0x2d0 [ 31.102706] do_error_trap+0x132/0x2d0 [ 31.106603] ? math_error+0x2d0/0x2d0 [ 31.110383] ? flags_string.cold+0x1b15/0x6a9f [ 31.114961] ? __mutex_lock+0x360/0x1310 [ 31.119004] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.123844] invalid_op+0x1b/0x40 [ 31.127367] RIP: 0010:flags_string.cold+0x1b15/0x6a9f [ 31.132554] RSP: 0018:ffff88809702fcd0 EFLAGS: 00010296 [ 31.137951] RAX: 0000000000000000 RBX: ffff8880b310b3d8 RCX: ffff8880b310b3d8 [ 31.145243] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 31.152508] RBP: ffffffff89512740 R08: 0000000000000000 R09: 0000000000000002 [ 31.159760] R10: 0000000000000000 R11: ffff8880951ec600 R12: 0000000000000000 [ 31.167017] R13: ffff88808e3481c4 R14: ffffed1011c69086 R15: dffffc0000000000 [ 31.174280] nbd_release+0xf3/0x150 [ 31.177889] ? nbd_queue_rq+0xc50/0xc50 [ 31.181842] __blkdev_put+0x5aa/0x800 [ 31.185624] ? revalidate_disk+0x1f0/0x1f0 [ 31.189937] ? locks_remove_file+0x2cd/0x420 [ 31.194348] ? blkdev_put+0x75/0x4c0 [ 31.198040] ? blkdev_put+0x4c0/0x4c0 [ 31.201828] blkdev_close+0x86/0xb0 [ 31.205443] __fput+0x25f/0x7a0 [ 31.208708] task_work_run+0x11f/0x190 [ 31.212586] exit_to_usermode_loop+0x1ad/0x200 [ 31.217197] do_syscall_64+0x4a3/0x640 [ 31.221091] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.226283] RIP: 0033:0x7f916dd3a270 [ 31.229975] RSP: 002b:00007ffc31691948 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 31.237701] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f916dd3a270 [ 31.244990] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 31.252252] RBP: 00007f916ebf4710 R08: 000055d45d3fbdf0 R09: 0000000000000018 [ 31.259500] R10: 000055d45d3fa8f8 R11: 0000000000000246 R12: 0000000000000000 [ 31.266763] R13: 000055d45d3fdeb0 R14: 0000000000000003 R15: 000000000000000e [ 31.274030] [ 31.275636] Allocated by task 8122: [ 31.279256] kasan_kmalloc+0xeb/0x160 [ 31.283053] kmem_cache_alloc_trace+0x131/0x3d0 [ 31.287700] nbd_dev_add+0x7c/0x800 [ 31.291329] nbd_genl_connect+0x3a4/0x1400 [ 31.295542] genl_family_rcv_msg+0x572/0xb20 [ 31.299978] genl_rcv_msg+0xaf/0x140 [ 31.303671] netlink_rcv_skb+0x125/0x390 [ 31.307711] genl_rcv+0x24/0x40 [ 31.310996] netlink_unicast+0x437/0x610 [ 31.315146] netlink_sendmsg+0x62e/0xb80 [ 31.319182] sock_sendmsg+0xb5/0x100 [ 31.322888] ___sys_sendmsg+0x6c8/0x800 [ 31.326855] __sys_sendmsg+0xa3/0x120 [ 31.330632] SyS_sendmsg+0x27/0x40 [ 31.334151] do_syscall_64+0x1d5/0x640 [ 31.338022] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.343193] [ 31.344805] Freed by task 8136: [ 31.348078] kasan_slab_free+0xc3/0x1a0 [ 31.352071] kfree+0xc9/0x250 [ 31.355154] nbd_put.part.0+0x100/0x140 [ 31.359118] nbd_genl_connect+0xfa9/0x1400 [ 31.363359] genl_family_rcv_msg+0x572/0xb20 [ 31.367762] genl_rcv_msg+0xaf/0x140 [ 31.371470] netlink_rcv_skb+0x125/0x390 [ 31.375508] genl_rcv+0x24/0x40 [ 31.378765] netlink_unicast+0x437/0x610 [ 31.385175] netlink_sendmsg+0x62e/0xb80 [ 31.389221] sock_sendmsg+0xb5/0x100 [ 31.392926] ___sys_sendmsg+0x6c8/0x800 [ 31.396896] __sys_sendmsg+0xa3/0x120 [ 31.400672] SyS_sendmsg+0x27/0x40 [ 31.404188] do_syscall_64+0x1d5/0x640 [ 31.408054] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.413216] [ 31.414867] The buggy address belongs to the object at ffff8880b310b300 [ 31.414867] which belongs to the cache kmalloc-512 of size 512 [ 31.427515] The buggy address is located 216 bytes inside of [ 31.427515] 512-byte region [ffff8880b310b300, ffff8880b310b500) [ 31.439364] The buggy address belongs to the page: [ 31.444285] page:ffffea0002cc42c0 count:1 mapcount:0 mapping:ffff8880b310b080 index:0xffff8880b310b800 [ 31.453798] flags: 0xfff00000000100(slab) [ 31.458020] raw: 00fff00000000100 ffff8880b310b080 ffff8880b310b800 0000000100000004 [ 31.465892] raw: ffffea0002aca920 ffffea0002b009a0 ffff88813fe80940 0000000000000000 [ 31.473747] page dumped because: kasan: bad access detected [ 31.480319] [ 31.481936] Memory state around the buggy address: [ 31.486867] ffff8880b310b280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 31.494205] ffff8880b310b300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.501540] >ffff8880b310b380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.508886] ^ [ 31.515092] ffff8880b310b400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.522430] ffff8880b310b480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.529764] ================================================================== [ 31.537099] Disabling lock debugging due to kernel taint [ 31.545732] Kernel panic - not syncing: panic_on_warn set ... [ 31.545732] [ 31.553106] CPU: 1 PID: 8145 Comm: systemd-udevd Tainted: G B 4.14.229-syzkaller #0 [ 31.562021] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.571517] Call Trace: [ 31.574102] dump_stack+0x1b2/0x281 [ 31.577724] panic+0x1f9/0x42d [ 31.580900] ? add_taint.cold+0x16/0x16 [ 31.584854] ? ___preempt_schedule+0x16/0x18 [ 31.589259] kasan_end_report+0x43/0x49 [ 31.593228] kasan_report_error.cold+0xa7/0x191 [ 31.597885] ? ex_handler_refcount+0x164/0x1a0 [ 31.602456] __asan_report_store4_noabort+0x68/0x70 [ 31.607457] ? ex_handler_refcount+0x164/0x1a0 [ 31.612021] ex_handler_refcount+0x164/0x1a0 [ 31.616409] ? ex_handler_clear_fs+0xb0/0xb0 [ 31.620816] fixup_exception+0x8a/0xd0 [ 31.624686] do_trap+0x61/0x250 [ 31.627952] ? do_error_trap+0x1d0/0x2d0 [ 31.632014] do_error_trap+0x132/0x2d0 [ 31.635878] ? math_error+0x2d0/0x2d0 [ 31.639654] ? flags_string.cold+0x1b15/0x6a9f [ 31.644212] ? __mutex_lock+0x360/0x1310 [ 31.648254] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.653074] invalid_op+0x1b/0x40 [ 31.656505] RIP: 0010:flags_string.cold+0x1b15/0x6a9f [ 31.661667] RSP: 0018:ffff88809702fcd0 EFLAGS: 00010296 [ 31.667007] RAX: 0000000000000000 RBX: ffff8880b310b3d8 RCX: ffff8880b310b3d8 [ 31.674269] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 31.681530] RBP: ffffffff89512740 R08: 0000000000000000 R09: 0000000000000002 [ 31.688798] R10: 0000000000000000 R11: ffff8880951ec600 R12: 0000000000000000 [ 31.696071] R13: ffff88808e3481c4 R14: ffffed1011c69086 R15: dffffc0000000000 [ 31.703353] nbd_release+0xf3/0x150 [ 31.706957] ? nbd_queue_rq+0xc50/0xc50 [ 31.710911] __blkdev_put+0x5aa/0x800 [ 31.714690] ? revalidate_disk+0x1f0/0x1f0 [ 31.718915] ? locks_remove_file+0x2cd/0x420 [ 31.723329] ? blkdev_put+0x75/0x4c0 [ 31.727035] ? blkdev_put+0x4c0/0x4c0 [ 31.730813] blkdev_close+0x86/0xb0 [ 31.734441] __fput+0x25f/0x7a0 [ 31.737698] task_work_run+0x11f/0x190 [ 31.741565] exit_to_usermode_loop+0x1ad/0x200 [ 31.746123] do_syscall_64+0x4a3/0x640 [ 31.750008] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.755173] RIP: 0033:0x7f916dd3a270 [ 31.758873] RSP: 002b:00007ffc31691948 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 31.766557] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f916dd3a270 [ 31.773824] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 31.781094] RBP: 00007f916ebf4710 R08: 000055d45d3fbdf0 R09: 0000000000000018 [ 31.788599] R10: 000055d45d3fa8f8 R11: 0000000000000246 R12: 0000000000000000 [ 31.795945] R13: 000055d45d3fdeb0 R14: 0000000000000003 R15: 000000000000000e [ 31.803703] Kernel Offset: disabled [ 31.807327] Rebooting in 86400 seconds..