IPVS: ftp: loaded support on port[0] = 21 netlink: 16 bytes leftover after parsing attributes in process `syz-executor398'. ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 7021 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 7021 Comm: syz-executor398 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x35 kernel/panic.c:582 report_bug+0x27b/0x2f0 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:175 [inline] fixup_bug arch/x86/kernel/traps.c:170 [inline] do_error_trap+0x12b/0x220 arch/x86/kernel/traps.c:267 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Code: e9 db fe ff ff 48 89 df e8 3c 95 1e fe e9 8a fe ff ff e8 02 81 e1 fd 48 c7 c7 c0 c6 71 88 c6 05 a9 fa f1 06 01 e8 97 f5 b2 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 RSP: 0018:ffffc90001077d38 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815cb321 RDI: fffff5200020ef99 RBP: 0000000000000003 R08: ffff888086502100 R09: ffffed1015ce66a1 R10: ffffed1015ce66a0 R11: ffff8880ae733507 R12: ffff8880a21c6040 R13: ffff8880a21c6044 R14: 00000000000002ab R15: ffff88809000c3c0 refcount_sub_and_test include/linux/refcount.h:261 [inline] refcount_dec_and_test include/linux/refcount.h:281 [inline] put_net include/net/net_namespace.h:264 [inline] free_nsproxy+0x445/0x4a0 kernel/nsproxy.c:206 switch_task_namespaces+0xaa/0xc0 kernel/nsproxy.c:252 do_exit+0xb2f/0x2dd0 kernel/exit.c:792 do_group_exit+0x125/0x340 kernel/exit.c:891 __do_sys_exit_group kernel/exit.c:902 [inline] __se_sys_exit_group kernel/exit.c:900 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:900 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x43f998 Code: Bad RIP value. RSP: 002b:00007ffef4fb50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000043f998 RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 RBP: 00000000004bfa10 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d11c0 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds..