IPVS: ftp: loaded support on port[0] = 21 netlink: 16 bytes leftover after parsing attributes in process `syz-executor975'. ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 8658 at lib/refcount.c:28 refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 8658 Comm: syz-executor975 Not tainted 5.6.0-rc6-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+0x1e9/0x30e lib/dump_stack.c:118 panic+0x264/0x7a0 kernel/panic.c:221 __warn+0x209/0x210 kernel/panic.c:582 report_bug+0x1ac/0x2d0 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] do_error_trap+0xca/0x1c0 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+0x15b/0x1a0 lib/refcount.c:28 Code: c7 14 00 d1 88 31 c0 e8 53 38 b3 fd 0f 0b eb 85 e8 da 59 e0 fd c6 05 2e 86 b1 05 01 48 c7 c7 40 00 d1 88 31 c0 e8 35 38 b3 fd <0f> 0b e9 64 ff ff ff e8 b9 59 e0 fd c6 05 0e 86 b1 05 01 48 c7 c7 RSP: 0018:ffffc90004117d98 EFLAGS: 00010246 RAX: bda07dc86d91cd00 RBX: 0000000000000003 RCX: ffff888096e6c1c0 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: ffffffff815e17a6 R09: fffffbfff121afc3 R10: fffffbfff121afc3 R11: 0000000000000000 R12: ffff88808c2ba040 R13: 0000000000000100 R14: ffff8880a9a7db60 R15: ffff88808c2ba044 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+0x343/0x3b0 kernel/nsproxy.c:206 do_exit+0x5ea/0x1f80 kernel/exit.c:800 do_group_exit+0x15e/0x2c0 kernel/exit.c:899 __do_sys_exit_group+0x13/0x20 kernel/exit.c:910 __se_sys_exit_group+0x10/0x10 kernel/exit.c:908 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:908 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x43f998 Code: 24 38 80 f9 3a 0f 85 5f 01 00 00 48 8d 74 24 34 48 8d 7c 24 38 83 ea 01 89 54 24 34 e8 61 f8 ff ff 83 f8 3c 41 89 c1 0f 87 3d <01> 00 00 8b 4c 24 34 85 c9 0f 8e 59 01 00 00 48 8b 54 24 38 c7 44 RSP: 002b:00007ffd16db08e8 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..