[ 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 '10.128.1.50' (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 syzkaller login: [ 30.557996] ================================================================== [ 30.565523] BUG: KASAN: use-after-free in ex_handler_refcount+0x164/0x1a0 [ 30.572459] Write of size 4 at addr ffff8880aa4965d8 by task systemd-udevd/8152 [ 30.580061] [ 30.581681] CPU: 1 PID: 8152 Comm: systemd-udevd Not tainted 4.14.307-syzkaller #0 [ 30.589398] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 [ 30.598798] Call Trace: [ 30.601379] dump_stack+0x1b2/0x281 [ 30.605010] print_address_description.cold+0x54/0x1d3 [ 30.610415] kasan_report_error.cold+0x8a/0x191 [ 30.615075] ? ex_handler_refcount+0x164/0x1a0 [ 30.619747] __asan_report_store4_noabort+0x68/0x70 [ 30.624792] ? ex_handler_refcount+0x164/0x1a0 [ 30.629366] ex_handler_refcount+0x164/0x1a0 [ 30.633767] ? ex_handler_clear_fs+0xb0/0xb0 [ 30.638168] fixup_exception+0x8a/0xd0 [ 30.642055] do_trap+0x61/0x250 [ 30.645331] ? do_error_trap+0x1d0/0x2d0 [ 30.649391] do_error_trap+0x132/0x2d0 [ 30.653278] ? math_error+0x2d0/0x2d0 [ 30.657071] ? flags_string.cold+0x1b3e/0x6c57 [ 30.661741] ? __mutex_lock+0x360/0x1310 [ 30.665831] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 30.670715] invalid_op+0x1b/0x40 [ 30.674168] RIP: 0010:flags_string.cold+0x1b3e/0x6c57 [ 30.679344] RSP: 0018:ffff8880953efcd0 EFLAGS: 00010296 [ 30.684704] RAX: 0000000000000000 RBX: ffff8880aa4965d8 RCX: ffff8880aa4965d8 [ 30.691964] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 30.699229] RBP: ffffffff89512060 R08: 0000000000000000 R09: 0000000000000002 [ 30.706588] R10: 0000000000000000 R11: ffff8880b074e280 R12: 0000000000000000 [ 30.713849] R13: ffff88808a05e884 R14: ffffed101140bd5e R15: dffffc0000000000 [ 30.721145] nbd_release+0xf3/0x150 [ 30.724868] ? nbd_ioctl+0xad0/0xad0 [ 30.728580] __blkdev_put+0x5aa/0x800 [ 30.732385] ? revalidate_disk+0x1f0/0x1f0 [ 30.736619] ? locks_remove_file+0x2cd/0x420 [ 30.741024] ? blkdev_put+0x75/0x4c0 [ 30.744821] ? blkdev_put+0x4c0/0x4c0 [ 30.748661] blkdev_close+0x86/0xb0 [ 30.752286] __fput+0x25f/0x7a0 [ 30.755583] task_work_run+0x11f/0x190 [ 30.759476] exit_to_usermode_loop+0x1ad/0x200 [ 30.764099] do_syscall_64+0x4a3/0x640 [ 30.767991] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 30.773197] RIP: 0033:0x7f82dc537270 [ 30.776898] RSP: 002b:00007ffd4959f978 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 30.784613] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f82dc537270 [ 30.791904] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 30.799160] RBP: 00007f82dd3f1710 R08: 0000561ed15ae4d0 R09: 0000000000000018 [ 30.806417] R10: 0000561ed15ba798 R11: 0000000000000246 R12: 0000000000000000 [ 30.813685] R13: 0000561ed15bec20 R14: 0000000000000003 R15: 000000000000000e [ 30.820955] [ 30.822568] Allocated by task 8128: [ 30.826488] kasan_kmalloc+0xeb/0x160 [ 30.830281] kmem_cache_alloc_trace+0x131/0x3d0 [ 30.834982] nbd_dev_add+0x7c/0x800 [ 30.838625] nbd_genl_connect+0x3a4/0x13e0 [ 30.842851] genl_family_rcv_msg+0x572/0xb20 [ 30.847457] genl_rcv_msg+0xaf/0x140 [ 30.851298] netlink_rcv_skb+0x125/0x390 [ 30.855472] genl_rcv+0x24/0x40 [ 30.858754] netlink_unicast+0x437/0x610 [ 30.862812] netlink_sendmsg+0x651/0xbc0 [ 30.866870] sock_sendmsg+0xb5/0x100 [ 30.870598] ___sys_sendmsg+0x6c8/0x800 [ 30.874641] __sys_sendmsg+0xa3/0x120 [ 30.878443] SyS_sendmsg+0x27/0x40 [ 30.882016] do_syscall_64+0x1d5/0x640 [ 30.885898] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 30.891071] [ 30.892689] Freed by task 8136: [ 30.895963] kasan_slab_free+0xc3/0x1a0 [ 30.900054] kfree+0xc9/0x250 [ 30.903159] nbd_put.part.0+0x100/0x140 [ 30.907128] nbd_genl_connect+0xcf6/0x13e0 [ 30.911356] genl_family_rcv_msg+0x572/0xb20 [ 30.915777] genl_rcv_msg+0xaf/0x140 [ 30.919613] netlink_rcv_skb+0x125/0x390 [ 30.923692] genl_rcv+0x24/0x40 [ 30.926962] netlink_unicast+0x437/0x610 [ 30.931015] netlink_sendmsg+0x651/0xbc0 [ 30.935066] sock_sendmsg+0xb5/0x100 [ 30.938792] ___sys_sendmsg+0x6c8/0x800 [ 30.942766] __sys_sendmsg+0xa3/0x120 [ 30.946558] SyS_sendmsg+0x27/0x40 [ 30.950091] do_syscall_64+0x1d5/0x640 [ 30.954002] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 30.959174] [ 30.960964] The buggy address belongs to the object at ffff8880aa496500 [ 30.960964] which belongs to the cache kmalloc-512 of size 512 [ 30.973656] The buggy address is located 216 bytes inside of [ 30.973656] 512-byte region [ffff8880aa496500, ffff8880aa496700) [ 30.985519] The buggy address belongs to the page: [ 30.990547] page:ffffea0002a92580 count:1 mapcount:0 mapping:ffff8880aa496000 index:0x0 [ 30.998705] flags: 0xfff00000000100(slab) [ 31.002862] raw: 00fff00000000100 ffff8880aa496000 0000000000000000 0000000100000006 [ 31.010733] raw: ffffea0002bf0ca0 ffffea0002c239a0 ffff88813fe74940 0000000000000000 [ 31.018669] page dumped because: kasan: bad access detected [ 31.024368] [ 31.025982] Memory state around the buggy address: [ 31.030990] ffff8880aa496480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 31.038775] ffff8880aa496500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.046131] >ffff8880aa496580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.053506] ^ executing program [ 31.059731] ffff8880aa496600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.067085] ffff8880aa496680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.074434] ================================================================== [ 31.081779] Disabling lock debugging due to kernel taint [ 31.089663] Kernel panic - not syncing: KASAN: panic_on_warn set ... [ 31.089663] [ 31.097649] CPU: 1 PID: 8152 Comm: systemd-udevd Tainted: G B 4.14.307-syzkaller #0 [ 31.106571] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 [ 31.115929] Call Trace: [ 31.118520] dump_stack+0x1b2/0x281 [ 31.122150] panic+0x21d/0x451 [ 31.125343] ? add_taint.cold+0x16/0x16 [ 31.129380] ? ___preempt_schedule+0x16/0x18 [ 31.133787] ? preempt_schedule_common+0x45/0xc0 [ 31.138740] ? ___preempt_schedule+0x16/0x18 [ 31.143140] check_panic_on_warn.cold+0x19/0x35 [ 31.147809] kasan_end_report+0x3a/0x40 [ 31.151796] kasan_report_error.cold+0xa7/0x191 [ 31.156457] ? ex_handler_refcount+0x164/0x1a0 [ 31.161028] __asan_report_store4_noabort+0x68/0x70 [ 31.166037] ? ex_handler_refcount+0x164/0x1a0 [ 31.170611] ex_handler_refcount+0x164/0x1a0 [ 31.175015] ? ex_handler_clear_fs+0xb0/0xb0 [ 31.179414] fixup_exception+0x8a/0xd0 [ 31.183296] do_trap+0x61/0x250 [ 31.186567] ? do_error_trap+0x1d0/0x2d0 [ 31.190618] do_error_trap+0x132/0x2d0 [ 31.194519] ? math_error+0x2d0/0x2d0 [ 31.198314] ? flags_string.cold+0x1b3e/0x6c57 [ 31.202888] ? __mutex_lock+0x360/0x1310 [ 31.206939] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.211778] invalid_op+0x1b/0x40 [ 31.215219] RIP: 0010:flags_string.cold+0x1b3e/0x6c57 [ 31.220413] RSP: 0018:ffff8880953efcd0 EFLAGS: 00010296 [ 31.225762] RAX: 0000000000000000 RBX: ffff8880aa4965d8 RCX: ffff8880aa4965d8 [ 31.233019] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 31.240295] RBP: ffffffff89512060 R08: 0000000000000000 R09: 0000000000000002 [ 31.247560] R10: 0000000000000000 R11: ffff8880b074e280 R12: 0000000000000000 [ 31.255008] R13: ffff88808a05e884 R14: ffffed101140bd5e R15: dffffc0000000000 [ 31.262277] nbd_release+0xf3/0x150 [ 31.265926] ? nbd_ioctl+0xad0/0xad0 [ 31.269653] __blkdev_put+0x5aa/0x800 [ 31.273457] ? revalidate_disk+0x1f0/0x1f0 [ 31.277689] ? locks_remove_file+0x2cd/0x420 [ 31.282094] ? blkdev_put+0x75/0x4c0 [ 31.285852] ? blkdev_put+0x4c0/0x4c0 [ 31.289948] blkdev_close+0x86/0xb0 [ 31.293604] __fput+0x25f/0x7a0 [ 31.296875] task_work_run+0x11f/0x190 [ 31.300758] exit_to_usermode_loop+0x1ad/0x200 [ 31.306109] do_syscall_64+0x4a3/0x640 [ 31.310015] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 31.315219] RIP: 0033:0x7f82dc537270 [ 31.318940] RSP: 002b:00007ffd4959f978 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 31.326640] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f82dc537270 [ 31.334095] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 31.341484] RBP: 00007f82dd3f1710 R08: 0000561ed15ae4d0 R09: 0000000000000018 [ 31.348777] R10: 0000561ed15ba798 R11: 0000000000000246 R12: 0000000000000000 [ 31.356157] R13: 0000561ed15bec20 R14: 0000000000000003 R15: 000000000000000e [ 31.363623] Kernel Offset: disabled [ 31.367357] Rebooting in 86400 seconds..