------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 8210 at lib/refcount.c:28 refcount_warn_saturate+0x135/0x140 lib/refcount.c:28
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8210 Comm: syz-executor.5 Not tainted 5.4.0-rc2-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+0x113/0x167 lib/dump_stack.c:113
 panic+0x22a/0x4e3 kernel/panic.c:221
 __warn.cold.10+0x25/0x2a kernel/panic.c:582
 report_bug+0x1b0/0x270 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:291
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:refcount_warn_saturate+0x135/0x140 lib/refcount.c:28
Code: 83 ee fd 0f 0b e9 51 ff ff ff 48 89 df e8 83 96 4c fe e9 1f ff ff ff 48 c7 c7 c0 48 cc 87 c6 05 98 d1 58 06 01 e8 b3 83 ee fd <0f> 0b e9 2a ff ff ff 0f 1f 40 00 55 be 04 00 00 00 48 89 e5 41 57
RSP: 0018:ffff888099867758 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8880a7081a44 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8a8f8360
RBP: ffff888099867768 R08: ffffed1015d06159 R09: ffffed1015d06159
R10: ffffed1015d06158 R11: ffff8880ae830ac7 R12: 0000000000000003
R13: 0000000000008100 R14: ffff8880a7081a44 R15: ffff88809305f580
 refcount_sub_and_test include/linux/refcount.h:261 [inline]
 sock_wfree+0x15a/0x1a0 net/core/sock.c:1965
 sctp_wfree+0x30b/0x960 net/sctp/socket.c:8998
 skb_release_head_state+0x9f/0x1a0 net/core/skbuff.c:652
 skb_release_all+0xd/0x50 net/core/skbuff.c:663
 __kfree_skb net/core/skbuff.c:679 [inline]
 consume_skb+0xad/0x2d0 net/core/skbuff.c:838
 sctp_chunk_destroy net/sctp/sm_make_chunk.c:1454 [inline]
 sctp_chunk_put+0x16b/0x260 net/sctp/sm_make_chunk.c:1481
 sctp_chunk_free+0x3f/0x50 net/sctp/sm_make_chunk.c:1468
 __sctp_outq_teardown+0x68e/0xc30 net/sctp/outqueue.c:256
 sctp_outq_free+0x9/0x10 net/sctp/outqueue.c:276
 sctp_association_free+0x1d5/0x711 net/sctp/associola.c:336
 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:929 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1317 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1184 [inline]
 sctp_do_sm+0x2f74/0x4b00 net/sctp/sm_sideeffect.c:1155
 sctp_primitive_ABORT+0x7c/0xc0 net/sctp/primitive.c:104
 sctp_close+0x227/0x7e0 net/sctp/socket.c:1513
 inet_release+0xc1/0x1c0 net/ipv4/af_inet.c:427
 __sock_release+0xc2/0x270 net/socket.c:590
 sock_close+0x13/0x20 net/socket.c:1268
 __fput+0x25a/0x770 fs/file_table.c:280
 ____fput+0x9/0x10 fs/file_table.c:313
 task_work_run+0x108/0x180 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x24e/0x2e0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x4e8/0x5d0 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x416041
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffff5219220 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000416041
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00ffffffffffffff R09: 00ffffffffffffff
R10: 00007ffff5219300 R11: 0000000000000293 R12: 000000000076bf20
R13: 0000000000770850 R14: 0000000000010487 R15: 000000000076bf2c
Kernel Offset: disabled
Rebooting in 86400 seconds..