[ 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 '10.128.0.90' (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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program 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: [ 41.824982] ================================================================== [ 41.832591] BUG: KASAN: use-after-free in refcount_dec_not_one+0x71/0x1d0 [ 41.839630] Read of size 4 at addr ffff8880b161e358 by task syz-executor576/8904 [ 41.847159] [ 41.848784] CPU: 0 PID: 8904 Comm: syz-executor576 Not tainted 4.19.190-syzkaller #0 [ 41.856660] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.866225] Call Trace: [ 41.868830] dump_stack+0x1fc/0x2ef [ 41.872469] print_address_description.cold+0x54/0x219 [ 41.877784] kasan_report_error.cold+0x8a/0x1b9 [ 41.882466] ? refcount_dec_not_one+0x71/0x1d0 [ 41.887065] kasan_report+0x8f/0xa0 [ 41.890687] ? refcount_dec_not_one+0x71/0x1d0 [ 41.895262] refcount_dec_not_one+0x71/0x1d0 [ 41.899679] ? refcount_dec_and_test_checked+0x20/0x20 [ 41.904954] ? nbd_config_put+0x5da/0x870 [ 41.909117] refcount_dec_and_mutex_lock+0x1c/0x80 [ 41.914046] nbd_genl_connect+0x11ee/0x1630 [ 41.918370] ? nbd_xmit_timeout+0x730/0x730 [ 41.922705] ? __sanitizer_cov_trace_switch+0x4b/0x80 [ 41.927915] ? validate_nla+0x270/0x820 [ 41.931891] ? nla_parse+0x1b2/0x290 [ 41.935616] genl_family_rcv_msg+0x642/0xc40 [ 41.940027] ? genl_rcv+0x40/0x40 [ 41.943476] ? genl_rcv_msg+0x12f/0x160 [ 41.947446] ? __mutex_add_waiter+0x160/0x160 [ 41.952120] ? __radix_tree_lookup+0x216/0x370 [ 41.956710] genl_rcv_msg+0xbf/0x160 [ 41.960424] netlink_rcv_skb+0x160/0x440 [ 41.964522] ? genl_family_rcv_msg+0xc40/0xc40 [ 41.969158] ? netlink_ack+0xae0/0xae0 [ 41.973060] ? genl_rcv+0x15/0x40 [ 41.976534] genl_rcv+0x24/0x40 [ 41.979815] netlink_unicast+0x4d5/0x690 [ 41.984071] ? netlink_sendskb+0x110/0x110 [ 41.988301] ? _copy_from_iter_full+0x229/0x7c0 [ 41.992986] ? __phys_addr_symbol+0x2c/0x70 [ 41.997308] ? __check_object_size+0x17b/0x3e0 [ 42.001913] netlink_sendmsg+0x6bb/0xc40 [ 42.005993] ? aa_af_perm+0x230/0x230 [ 42.009799] ? nlmsg_notify+0x1a0/0x1a0 [ 42.013783] ? kernel_recvmsg+0x220/0x220 [ 42.017926] ? nlmsg_notify+0x1a0/0x1a0 [ 42.021912] sock_sendmsg+0xc3/0x120 [ 42.025712] ___sys_sendmsg+0x7bb/0x8e0 [ 42.029686] ? copy_msghdr_from_user+0x440/0x440 [ 42.034794] ? netlink_dump+0xc10/0xc10 [ 42.038766] ? nlmsg_notify+0x1a0/0x1a0 [ 42.042798] ? security_socket_recvmsg+0x8f/0xc0 [ 42.047561] ? __sys_recvfrom+0x2cd/0x3a0 [ 42.051703] ? __ia32_sys_send+0x100/0x100 [ 42.055957] ? __fdget+0x1a0/0x230 [ 42.059519] __x64_sys_sendmsg+0x132/0x220 [ 42.063947] ? __sys_sendmsg+0x1b0/0x1b0 [ 42.068008] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 42.073375] ? trace_hardirqs_off_caller+0x6e/0x210 [ 42.078420] ? do_syscall_64+0x21/0x620 [ 42.082390] do_syscall_64+0xf9/0x620 [ 42.086780] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 42.091978] RIP: 0033:0x4412d9 [ 42.095175] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c4 ff ff ff f7 d8 64 89 01 48 [ 42.114083] RSP: 002b:00007fff94878b78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 42.121798] RAX: ffffffffffffffda RBX: 00007fff94878be0 RCX: 00000000004412d9 [ 42.129075] RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000004 [ 42.136365] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 42.143765] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff94878bd0 [ 42.151220] R13: 000000000000a32b R14: 00007fff94878bcc R15: 431bde82d7b634db [ 42.158496] [ 42.160113] Allocated by task 8899: [ 42.163740] kmem_cache_alloc_trace+0x12f/0x380 [ 42.168420] nbd_dev_add+0x44/0x890 [ 42.172052] nbd_genl_connect+0x4cc/0x1630 [ 42.176363] genl_family_rcv_msg+0x642/0xc40 [ 42.180756] genl_rcv_msg+0xbf/0x160 [ 42.184464] netlink_rcv_skb+0x160/0x440 [ 42.188526] genl_rcv+0x24/0x40 [ 42.191805] netlink_unicast+0x4d5/0x690 [ 42.195874] netlink_sendmsg+0x6bb/0xc40 [ 42.199951] sock_sendmsg+0xc3/0x120 [ 42.203692] ___sys_sendmsg+0x7bb/0x8e0 [ 42.207653] __x64_sys_sendmsg+0x132/0x220 [ 42.211895] do_syscall_64+0xf9/0x620 [ 42.215799] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 42.220997] [ 42.222613] Freed by task 8904: [ 42.225896] kfree+0xcc/0x210 [ 42.229003] nbd_put.part.0+0xfe/0x140 [ 42.232888] nbd_config_put+0x6a0/0x870 [ 42.236850] nbd_genl_connect+0x11bb/0x1630 [ 42.241173] genl_family_rcv_msg+0x642/0xc40 [ 42.245601] genl_rcv_msg+0xbf/0x160 [ 42.249346] netlink_rcv_skb+0x160/0x440 [ 42.253403] genl_rcv+0x24/0x40 [ 42.256678] netlink_unicast+0x4d5/0x690 [ 42.260748] netlink_sendmsg+0x6bb/0xc40 [ 42.264812] sock_sendmsg+0xc3/0x120 [ 42.268520] ___sys_sendmsg+0x7bb/0x8e0 [ 42.272516] __x64_sys_sendmsg+0x132/0x220 [ 42.276758] do_syscall_64+0xf9/0x620 [ 42.280558] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 42.285726] [ 42.287342] The buggy address belongs to the object at ffff8880b161e280 [ 42.287342] which belongs to the cache kmalloc-512 of size 512 [ 42.300095] The buggy address is located 216 bytes inside of [ 42.300095] 512-byte region [ffff8880b161e280, ffff8880b161e480) [ 42.311956] The buggy address belongs to the page: [ 42.316877] page:ffffea0002c58780 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 [ 42.325012] flags: 0xfff00000000100(slab) [ 42.329168] raw: 00fff00000000100 ffffea0002c14e08 ffffea00028cba48 ffff88813bff0940 [ 42.337049] raw: 0000000000000000 ffff8880b161e000 0000000100000006 0000000000000000 [ 42.344984] page dumped because: kasan: bad access detected [ 42.350680] [ 42.352307] Memory state around the buggy address: [ 42.357266] ffff8880b161e200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 42.364618] ffff8880b161e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.372195] >ffff8880b161e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.380402] ^ [ 42.386646] ffff8880b161e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.394001] ffff8880b161e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.401636] ================================================================== [ 42.409090] Disabling lock debugging due to kernel taint [ 42.423643] Kernel panic - not syncing: panic_on_warn set ... [ 42.423643] [ 42.431033] CPU: 1 PID: 8904 Comm: syz-executor576 Tainted: G B 4.19.190-syzkaller #0 [ 42.440323] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.449709] Call Trace: [ 42.452329] dump_stack+0x1fc/0x2ef [ 42.455982] panic+0x26a/0x50e [ 42.459168] ? __warn_printk+0xf3/0xf3 [ 42.463066] ? preempt_schedule_common+0x45/0xc0 [ 42.467829] ? ___preempt_schedule+0x16/0x18 [ 42.472241] ? trace_hardirqs_on+0x55/0x210 [ 42.476567] kasan_end_report+0x43/0x49 [ 42.480547] kasan_report_error.cold+0xa7/0x1b9 [ 42.485220] ? refcount_dec_not_one+0x71/0x1d0 [ 42.489795] kasan_report+0x8f/0xa0 [ 42.493442] ? refcount_dec_not_one+0x71/0x1d0 [ 42.498027] refcount_dec_not_one+0x71/0x1d0 [ 42.502442] ? refcount_dec_and_test_checked+0x20/0x20 [ 42.507712] ? nbd_config_put+0x5da/0x870 [ 42.511849] refcount_dec_and_mutex_lock+0x1c/0x80 [ 42.516781] nbd_genl_connect+0x11ee/0x1630 [ 42.521094] ? nbd_xmit_timeout+0x730/0x730 [ 42.525426] ? __sanitizer_cov_trace_switch+0x4b/0x80 [ 42.530610] ? validate_nla+0x270/0x820 [ 42.534580] ? nla_parse+0x1b2/0x290 [ 42.538293] genl_family_rcv_msg+0x642/0xc40 [ 42.542708] ? genl_rcv+0x40/0x40 [ 42.546203] ? genl_rcv_msg+0x12f/0x160 [ 42.550174] ? __mutex_add_waiter+0x160/0x160 [ 42.554663] ? __radix_tree_lookup+0x216/0x370 [ 42.559266] genl_rcv_msg+0xbf/0x160 [ 42.562982] netlink_rcv_skb+0x160/0x440 [ 42.567032] ? genl_family_rcv_msg+0xc40/0xc40 [ 42.571596] ? netlink_ack+0xae0/0xae0 [ 42.575468] ? genl_rcv+0x15/0x40 [ 42.578902] genl_rcv+0x24/0x40 [ 42.582165] netlink_unicast+0x4d5/0x690 [ 42.586220] ? netlink_sendskb+0x110/0x110 [ 42.590488] ? _copy_from_iter_full+0x229/0x7c0 [ 42.595156] ? __phys_addr_symbol+0x2c/0x70 [ 42.599554] ? __check_object_size+0x17b/0x3e0 [ 42.604229] netlink_sendmsg+0x6bb/0xc40 [ 42.608382] ? aa_af_perm+0x230/0x230 [ 42.612178] ? nlmsg_notify+0x1a0/0x1a0 [ 42.616150] ? kernel_recvmsg+0x220/0x220 [ 42.620313] ? nlmsg_notify+0x1a0/0x1a0 [ 42.624283] sock_sendmsg+0xc3/0x120 [ 42.628178] ___sys_sendmsg+0x7bb/0x8e0 [ 42.632164] ? copy_msghdr_from_user+0x440/0x440 [ 42.636927] ? netlink_dump+0xc10/0xc10 [ 42.640893] ? nlmsg_notify+0x1a0/0x1a0 [ 42.644873] ? security_socket_recvmsg+0x8f/0xc0 [ 42.649732] ? __sys_recvfrom+0x2cd/0x3a0 [ 42.653871] ? __ia32_sys_send+0x100/0x100 [ 42.658123] ? __fdget+0x1a0/0x230 [ 42.661914] __x64_sys_sendmsg+0x132/0x220 [ 42.666154] ? __sys_sendmsg+0x1b0/0x1b0 [ 42.670207] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 42.675707] ? trace_hardirqs_off_caller+0x6e/0x210 [ 42.680737] ? do_syscall_64+0x21/0x620 [ 42.684722] do_syscall_64+0xf9/0x620 [ 42.688567] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 42.693837] RIP: 0033:0x4412d9 [ 42.697105] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c4 ff ff ff f7 d8 64 89 01 48 [ 42.716051] RSP: 002b:00007fff94878b78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 42.723779] RAX: ffffffffffffffda RBX: 00007fff94878be0 RCX: 00000000004412d9 [ 42.731491] RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000004 [ 42.738759] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 42.746060] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff94878bd0 [ 42.753579] R13: 000000000000a32b R14: 00007fff94878bcc R15: 431bde82d7b634db [ 42.761843] Kernel Offset: disabled [ 42.765494] Rebooting in 86400 seconds..