[ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started getty on tty2-tty6 if dbus and logind are not available. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.106' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 65.342808][ T7050] IPVS: ftp: loaded support on port[0] = 21 [ 65.382163][ T7050] netlink: 16 bytes leftover after parsing attributes in process `syz-executor853'. [ 65.425689][ T7050] ------------[ cut here ]------------ [ 65.431173][ T7050] refcount_t: underflow; use-after-free. [ 65.437427][ T7050] WARNING: CPU: 1 PID: 7050 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 65.446803][ T7050] Kernel panic - not syncing: panic_on_warn set ... [ 65.453381][ T7050] CPU: 1 PID: 7050 Comm: syz-executor853 Not tainted 5.6.0-rc7-syzkaller #0 [ 65.462074][ T7050] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.472121][ T7050] Call Trace: [ 65.475406][ T7050] dump_stack+0x188/0x20d [ 65.479762][ T7050] ? refcount_warn_saturate+0x190/0x1e0 [ 65.485326][ T7050] panic+0x2e3/0x75c [ 65.489215][ T7050] ? add_taint.cold+0x16/0x16 [ 65.493911][ T7050] ? __probe_kernel_read+0x188/0x1d0 [ 65.499194][ T7050] ? __warn.cold+0x14/0x35 [ 65.503640][ T7050] ? __warn+0xd5/0x1c8 [ 65.507726][ T7050] ? refcount_warn_saturate+0x1d1/0x1e0 [ 65.513267][ T7050] __warn.cold+0x2f/0x35 [ 65.517542][ T7050] ? refcount_warn_saturate+0x1d1/0x1e0 [ 65.523092][ T7050] report_bug+0x27b/0x2f0 [ 65.527564][ T7050] do_error_trap+0x12b/0x220 [ 65.532141][ T7050] ? refcount_warn_saturate+0x1d1/0x1e0 [ 65.537695][ T7050] do_invalid_op+0x32/0x40 [ 65.542112][ T7050] ? refcount_warn_saturate+0x1d1/0x1e0 [ 65.547663][ T7050] invalid_op+0x23/0x30 [ 65.551942][ T7050] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 65.558097][ T7050] Code: e9 db fe ff ff 48 89 df e8 4c 63 1f fe e9 8a fe ff ff e8 f2 99 e2 fd 48 c7 c7 00 a9 51 88 c6 05 c6 a0 d1 06 01 e8 d7 aa b4 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 65.577704][ T7050] RSP: 0018:ffffc900015b7d38 EFLAGS: 00010286 [ 65.583778][ T7050] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 65.591807][ T7050] RDX: 0000000000000000 RSI: ffffffff815c06c1 RDI: fffff520002b6f99 [ 65.599769][ T7050] RBP: 0000000000000003 R08: ffff888094ace100 R09: ffffed1015ce6659 [ 65.607758][ T7050] R10: ffffed1015ce6658 R11: ffff8880ae7332c7 R12: ffff888094bba040 [ 65.615770][ T7050] R13: ffff888094bba044 R14: 00000000000002ab R15: ffff88809dfba180 [ 65.623779][ T7050] ? vprintk_func+0x81/0x17e [ 65.628383][ T7050] ? refcount_warn_saturate+0x1d1/0x1e0 [ 65.633966][ T7050] free_nsproxy+0x445/0x4a0 [ 65.638536][ T7050] switch_task_namespaces+0xaa/0xc0 [ 65.643786][ T7050] do_exit+0xb2f/0x2dd0 [ 65.647944][ T7050] ? mm_update_next_owner+0x7a0/0x7a0 [ 65.653297][ T7050] ? up_read+0x1ab/0x750 [ 65.657520][ T7050] ? mark_held_locks+0x9f/0xe0 [ 65.662262][ T7050] ? down_read_non_owner+0x470/0x470 [ 65.667553][ T7050] ? handle_mm_fault+0x491/0xa10 [ 65.672490][ T7050] do_group_exit+0x125/0x340 [ 65.677068][ T7050] __x64_sys_exit_group+0x3a/0x50 [ 65.682098][ T7050] do_syscall_64+0xf6/0x7d0 [ 65.686639][ T7050] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.692512][ T7050] RIP: 0033:0x43f998 [ 65.696393][ T7050] Code: Bad RIP value. [ 65.700435][ T7050] RSP: 002b:00007fff88828ec8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 65.708858][ T7050] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000043f998 [ 65.716806][ T7050] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 65.724753][ T7050] RBP: 00000000004bfa10 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 65.732702][ T7050] R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000000001 [ 65.740652][ T7050] R13: 00000000006d11c0 R14: 0000000000000000 R15: 0000000000000000 [ 65.750101][ T7050] Kernel Offset: disabled [ 65.754480][ T7050] Rebooting in 86400 seconds..