[ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ 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 '10.128.10.2' (ECDSA) to the list of known hosts. syzkaller login: [ 32.776345] IPVS: ftp: loaded support on port[0] = 21 executing program [ 32.872666] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 32.881398] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 32.890043] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 32.898655] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 32.907777] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. executing program [ 32.971400] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 32.980061] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 32.988624] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 32.998176] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. [ 33.007728] netlink: 4 bytes leftover after parsing attributes in process `syz-executor281'. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 37.718847] ================================================================== [ 37.726328] BUG: KASAN: use-after-free in refcount_dec_not_one+0x71/0x1d0 [ 37.733251] Read of size 4 at addr ffff8880aa77a618 by task systemd-udevd/8945 [ 37.740585] [ 37.742193] CPU: 0 PID: 8945 Comm: systemd-udevd Not tainted 4.19.211-syzkaller #0 [ 37.749874] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 [ 37.759202] Call Trace: [ 37.761819] dump_stack+0x1fc/0x2ef [ 37.765439] print_address_description.cold+0x54/0x219 [ 37.770696] kasan_report_error.cold+0x8a/0x1b9 [ 37.775347] ? refcount_dec_not_one+0x71/0x1d0 [ 37.779919] kasan_report+0x8f/0xa0 [ 37.783545] ? refcount_dec_not_one+0x71/0x1d0 [ 37.788111] refcount_dec_not_one+0x71/0x1d0 [ 37.792506] ? refcount_dec_and_test_checked+0x20/0x20 [ 37.797762] ? nbd_config_put+0x5da/0x870 [ 37.801888] refcount_dec_and_mutex_lock+0x1c/0x80 [ 37.806796] nbd_release+0x108/0x170 [ 37.810502] ? nbd_queue_rq+0xe60/0xe60 [ 37.814473] __blkdev_put+0x636/0x870 [ 37.818259] ? fsync_bdev+0xc0/0xc0 [ 37.821863] ? locks_remove_file+0x2cd/0x450 [ 37.826252] ? blkdev_put+0x85/0x520 [ 37.829944] ? blkdev_put+0x520/0x520 [ 37.833811] blkdev_close+0x86/0xb0 [ 37.837417] __fput+0x2ce/0x890 [ 37.840697] task_work_run+0x148/0x1c0 [ 37.844601] exit_to_usermode_loop+0x251/0x2a0 [ 37.849175] do_syscall_64+0x538/0x620 [ 37.853051] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.858222] RIP: 0033:0x7f8d15167270 [ 37.861924] Code: 73 01 c3 48 8b 0d 38 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 59 c1 20 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ee fb ff ff 48 89 04 24 [ 37.880805] RSP: 002b:00007ffd646432b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 37.888492] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f8d15167270 [ 37.895742] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 37.903005] RBP: 00007f8d16021710 R08: 000000000000004a R09: 0000000000000008 [ 37.910256] R10: 00005598b0258758 R11: 0000000000000246 R12: 0000000000000000 [ 37.917509] R13: 00005598b025b880 R14: 0000000000000003 R15: 000000000000000e [ 37.924816] [ 37.926424] Allocated by task 8944: [ 37.930043] kmem_cache_alloc_trace+0x12f/0x380 [ 37.934797] nbd_dev_add+0x44/0x890 [ 37.938404] nbd_genl_connect+0x4cc/0x1630 [ 37.942618] genl_family_rcv_msg+0x642/0xc40 [ 37.947004] genl_rcv_msg+0xbf/0x160 [ 37.950694] netlink_rcv_skb+0x160/0x440 [ 37.954788] genl_rcv+0x24/0x40 [ 37.958060] netlink_unicast+0x4d5/0x690 [ 37.962116] netlink_sendmsg+0x6c3/0xc50 [ 37.966161] sock_sendmsg+0xc3/0x120 [ 37.969853] ___sys_sendmsg+0x7bb/0x8e0 [ 37.973809] __x64_sys_sendmsg+0x132/0x220 [ 37.978021] do_syscall_64+0xf9/0x620 [ 37.981800] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.986964] [ 37.988572] Freed by task 8945: [ 37.991852] kfree+0xcc/0x210 [ 37.994944] nbd_put.part.0+0xfe/0x140 [ 37.998815] nbd_config_put+0x6a0/0x870 [ 38.002769] nbd_release+0xf4/0x170 [ 38.006374] __blkdev_put+0x636/0x870 [ 38.010158] blkdev_close+0x86/0xb0 [ 38.013774] __fput+0x2ce/0x890 [ 38.017033] task_work_run+0x148/0x1c0 [ 38.020901] exit_to_usermode_loop+0x251/0x2a0 [ 38.025469] do_syscall_64+0x538/0x620 [ 38.029344] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.034503] [ 38.036111] The buggy address belongs to the object at ffff8880aa77a540 [ 38.036111] which belongs to the cache kmalloc-512 of size 512 [ 38.048747] The buggy address is located 216 bytes inside of [ 38.048747] 512-byte region [ffff8880aa77a540, ffff8880aa77a740) [ 38.060597] The buggy address belongs to the page: [ 38.065506] page:ffffea0002a9de80 count:1 mapcount:0 mapping:ffff88813bff0940 index:0xffff8880aa77aa40 [ 38.074928] flags: 0xfff00000000100(slab) [ 38.079059] raw: 00fff00000000100 ffffea0002a67e88 ffffea0002a68d08 ffff88813bff0940 [ 38.086924] raw: ffff8880aa77aa40 ffff8880aa77a040 0000000100000005 0000000000000000 [ 38.094782] page dumped because: kasan: bad access detected [ 38.100468] [ 38.102074] Memory state around the buggy address: [ 38.106981] ffff8880aa77a500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 38.114320] ffff8880aa77a580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.121657] >ffff8880aa77a600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.128992] ^ [ 38.133115] ffff8880aa77a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.140448] ffff8880aa77a700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 38.147777] ================================================================== [ 38.155124] Disabling lock debugging due to kernel taint [ 38.164037] Kernel panic - not syncing: panic_on_warn set ... [ 38.164037] [ 38.171407] CPU: 0 PID: 8945 Comm: systemd-udevd Tainted: G B 4.19.211-syzkaller #0 [ 38.180496] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 [ 38.189834] Call Trace: [ 38.192402] dump_stack+0x1fc/0x2ef [ 38.196008] panic+0x26a/0x50e [ 38.199176] ? __warn_printk+0xf3/0xf3 [ 38.203040] ? preempt_schedule_common+0x45/0xc0 [ 38.207772] ? ___preempt_schedule+0x16/0x18 [ 38.212158] ? trace_hardirqs_on+0x55/0x210 [ 38.216462] kasan_end_report+0x43/0x49 [ 38.220416] kasan_report_error.cold+0xa7/0x1b9 [ 38.225076] ? refcount_dec_not_one+0x71/0x1d0 [ 38.229645] kasan_report+0x8f/0xa0 [ 38.233251] ? refcount_dec_not_one+0x71/0x1d0 [ 38.237809] refcount_dec_not_one+0x71/0x1d0 [ 38.242195] ? refcount_dec_and_test_checked+0x20/0x20 [ 38.247509] ? nbd_config_put+0x5da/0x870 [ 38.251645] refcount_dec_and_mutex_lock+0x1c/0x80 [ 38.256559] nbd_release+0x108/0x170 [ 38.260253] ? nbd_queue_rq+0xe60/0xe60 [ 38.264205] __blkdev_put+0x636/0x870 [ 38.267985] ? fsync_bdev+0xc0/0xc0 [ 38.271588] ? locks_remove_file+0x2cd/0x450 [ 38.275974] ? blkdev_put+0x85/0x520 [ 38.279669] ? blkdev_put+0x520/0x520 [ 38.283495] blkdev_close+0x86/0xb0 [ 38.287104] __fput+0x2ce/0x890 [ 38.290379] task_work_run+0x148/0x1c0 [ 38.294250] exit_to_usermode_loop+0x251/0x2a0 [ 38.298811] do_syscall_64+0x538/0x620 [ 38.302679] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.307862] RIP: 0033:0x7f8d15167270 [ 38.311562] Code: 73 01 c3 48 8b 0d 38 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 59 c1 20 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ee fb ff ff 48 89 04 24 [ 38.330444] RSP: 002b:00007ffd646432b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 38.338245] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f8d15167270 [ 38.345492] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 38.352743] RBP: 00007f8d16021710 R08: 000000000000004a R09: 0000000000000008 [ 38.359994] R10: 00005598b0258758 R11: 0000000000000246 R12: 0000000000000000 [ 38.367256] R13: 00005598b025b880 R14: 0000000000000003 R15: 000000000000000e [ 38.374773] Kernel Offset: disabled [ 38.378383] Rebooting in 86400 seconds..