------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 24446 at lib/refcount.c:187 refcount_sub_and_test_checked+0x2c9/0x310 lib/refcount.c:187
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 24446 Comm: syz-executor5 Not tainted 4.19.0-rc3+ #134
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 panic+0x238/0x4e7 kernel/panic.c:184
 __warn.cold.8+0x163/0x1ba kernel/panic.c:536
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:993
RIP: 0010:refcount_sub_and_test_checked+0x2c9/0x310 lib/refcount.c:187
Code: 89 de e8 ea 8f ef fd 84 db 74 07 31 db e9 4d ff ff ff e8 0a 8f ef fd 48 c7 c7 e0 80 44 88 c6 05 76 84 91 06 01 e8 57 79 b9 fd <0f> 0b 31 db e9 2c ff ff ff 48 89 cf e8 e6 f5 32 fe e9 41 fe ff ff
RSP: 0018:ffff8801daf075a0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000100 RSI: ffffffff8164f955 RDI: 0000000000000005
RBP: ffff8801daf07688 R08: ffff88019b7c2400 R09: ffffed003b5e3ee2
R10: ffffed003b5e3ee2 R11: ffff8801daf1f717 R12: ffff88019bfd0020
R13: 00000000ffffffff R14: ffff8801daf07660 R15: ffff8801cd038dc8
 refcount_dec_and_test_checked+0x1a/0x20 lib/refcount.c:212
 sctp_transport_put+0x76/0x1f0 net/sctp/transport.c:331
 sctp_generate_heartbeat_event+0x187/0x480 net/sctp/sm_sideeffect.c:416
 call_timer_fn+0x272/0x920 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers+0x7e5/0xc70 kernel/time/timer.c:1682
 run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1695
 __do_softirq+0x30b/0xad8 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1056
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:864
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:788 [inline]
RIP: 0010:kmem_cache_free+0xb0/0x290 mm/slab.c:3757
Code: 84 e6 00 00 00 41 f7 c5 00 02 00 00 0f 84 b7 00 00 00 e8 93 dd c2 ff 48 83 3d e3 2a 90 07 00 0f 84 d0 01 00 00 4c 89 ef 57 9d <0f> 1f 44 00 00 4c 8b 6d 08 0f 1f 44 00 00 65 8b 05 0b 82 3f 7e 83
RSP: 0018:ffff8801997afca0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff8801da972d80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000282
RBP: ffff8801997afcc0 R08: ffff88019b7c2400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c46c42c0
R13: 0000000000000282 R14: ffffffff81d2d162 R15: ffff8801b8fce668
 putname+0xf2/0x130 fs/namei.c:261
 do_sys_open+0x54d/0x700 fs/open.c:1072
 ksys_open include/linux/syscalls.h:1276 [inline]
 __do_sys_creat fs/open.c:1121 [inline]
 __se_sys_creat fs/open.c:1119 [inline]
 __ia32_sys_creat+0x5f/0x80 fs/open.c:1119
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f7dca9
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 0c 24 c3 8b 1c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f5f580cc EFLAGS: 00000296 ORIG_RAX: 0000000000000008
RAX: ffffffffffffffda RBX: 00000000200000c0 RCX: 0000000000000104
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..