------------[ cut here ]------------ refcount_t: increment on 0; use-after-free. WARNING: CPU: 0 PID: 11724 at lib/refcount.c:156 refcount_inc_checked /lib/refcount.c:156 [inline] WARNING: CPU: 0 PID: 11724 at lib/refcount.c:156 refcount_inc_checked+0x61/0x70 /lib/refcount.c:154 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 11724 Comm: syz-executor.1 Not tainted 5.2.0-next-20190718 #41 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+0x172/0x1f0 /lib/dump_stack.c:113 panic+0x2dc/0x755 /kernel/panic.c:219 __warn.cold+0x20/0x4c /kernel/panic.c:576 report_bug+0x263/0x2b0 /lib/bug.c:186 fixup_bug /arch/x86/kernel/traps.c:179 [inline] fixup_bug /arch/x86/kernel/traps.c:174 [inline] do_error_trap+0x11b/0x200 /arch/x86/kernel/traps.c:272 do_invalid_op+0x37/0x50 /arch/x86/kernel/traps.c:291 invalid_op+0x14/0x20 /arch/x86/entry/entry_64.S:1008 RIP: 0010:refcount_inc_checked /lib/refcount.c:156 [inline] RIP: 0010:refcount_inc_checked+0x61/0x70 /lib/refcount.c:154 Code: 1d 5f 47 64 06 31 ff 89 de e8 db 80 35 fe 84 db 75 dd e8 92 7f 35 fe 48 c7 c7 80 0d c6 87 c6 05 3f 47 64 06 01 e8 77 e7 06 fe <0f> 0b eb c1 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 RSP: 0018:ffff8880ae809bf0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000100 RSI: ffffffff815c3a26 RDI: ffffed1015d01370 RBP: ffff8880ae809c00 R08: ffff8880996ee680 R09: fffffbfff14a7d59 R10: fffffbfff14a7d58 R11: ffffffff8a53eac7 R12: ffff88809c06d4c0 R13: ffff88809c06d4a8 R14: ffff88809242b208 R15: ffff88809242b1e0 sock_hold /./include/net/sock.h:649 [inline] sk_add_node /./include/net/sock.h:701 [inline] nr_insert_socket+0x2d/0xe0 /net/netrom/af_netrom.c:137 nr_rx_frame+0x1605/0x1e73 /net/netrom/af_netrom.c:1023 nr_loopback_timer+0x7b/0x170 /net/netrom/nr_loopback.c:59 call_timer_fn+0x1ac/0x780 /kernel/time/timer.c:1322 expire_timers /kernel/time/timer.c:1366 [inline] __run_timers /kernel/time/timer.c:1685 [inline] __run_timers /kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 /kernel/time/timer.c:1698 __do_softirq+0x262/0x98c /kernel/softirq.c:292 invoke_softirq /kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 /kernel/softirq.c:413 exiting_irq /./arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 /arch/x86/kernel/apic/apic.c:1095 apic_timer_interrupt+0xf/0x20 /arch/x86/entry/entry_64.S:828 RIP: 0010:debug_lockdep_rcu_enabled.part.0+0x2a/0x60 /kernel/rcu/update.c:237 Code: 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 53 65 48 8b 1c 25 c0 fd 01 00 48 8d bb 94 08 00 00 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 10 8b 93 94 08 00 RSP: 0018:ffff888091917a40 EFLAGS: 00000a07 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff8880996ee680 RCX: 1ffffffff134aa3e RDX: 0000000000000000 RSI: ffffffff86155c8d RDI: ffff8880996eef14 RBP: ffff888091917a48 R08: ffff8880996ee680 R09: ffffed1015d06c7c R10: ffffed1015d06c7b R11: ffff8880ae8363db R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff882fe140 R15: 0000000000000000 debug_lockdep_rcu_enabled+0x71/0xa0 /kernel/rcu/update.c:236 rcu_read_unlock /./include/linux/rcupdate.h:642 [inline] igmp_mc_seq_stop+0x89/0x140 /net/ipv4/igmp.c:2825 seq_read+0x6aa/0x1110 /fs/seq_file.c:249 proc_reg_read+0x1fc/0x2c0 /fs/proc/inode.c:223 do_loop_readv_writev /fs/read_write.c:714 [inline] do_loop_readv_writev /fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 /fs/read_write.c:935 vfs_readv+0xf0/0x160 /fs/read_write.c:997 do_preadv+0x1c4/0x280 /fs/read_write.c:1089 __do_sys_preadv /fs/read_write.c:1139 [inline] __se_sys_preadv /fs/read_write.c:1134 [inline] __x64_sys_preadv+0x9a/0xf0 /fs/read_write.c:1134 do_syscall_64+0xfd/0x6a0 /arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459819 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f267a8b4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459819 RDX: 100000000000022c RSI: 0000000020000480 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 6c00000000000000 R11: 0000000000000246 R12: 00007f267a8b56d4 R13: 00000000004c69c8 R14: 00000000004db908 R15: 00000000ffffffff Kernel Offset: disabled Rebooting in 86400 seconds..