IPVS: ftp: loaded support on port[0] = 21 netlink: 16 bytes leftover after parsing attributes in process `syz-executor796'. ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 9590 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9590 Comm: syz-executor796 Not tainted 5.6.0-rc5-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:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [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 9c 10 20 fe e9 8a fe ff ff e8 62 52 e3 fd 48 c7 c7 00 aa 51 88 c6 05 85 68 d2 06 01 e8 d7 62 b5 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:ffffc90001ff7d28 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815bf511 RDI: fffff520003fef97 RBP: 0000000000000003 R08: ffff8880865dc600 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888096da2040 R13: ffff888096da2044 R14: 0000000000000281 R15: ffff88808bd311c0 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:259 [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:800 do_group_exit+0x125/0x340 kernel/exit.c:899 __do_sys_exit_group kernel/exit.c:910 [inline] __se_sys_exit_group kernel/exit.c:908 [inline] __ia32_sys_exit_group+0x3a/0x50 kernel/exit.c:908 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x270/0xe8f arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 Kernel Offset: disabled Rebooting in 86400 seconds..