------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 7842 at lib/refcount.c:190 refcount_sub_and_test_checked+0x1d6/0x230 lib/refcount.c:190 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 7842 Comm: syz-executor278 Not tainted 5.4.0-rc8-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+0x1fb/0x318 lib/dump_stack.c:118 panic+0x264/0x7a9 kernel/panic.c:221 __warn+0x20e/0x210 kernel/panic.c:582 report_bug+0x1b6/0x2f0 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:179 [inline] do_error_trap+0xd7/0x440 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_sub_and_test_checked+0x1d6/0x230 lib/refcount.c:190 Code: 75 05 01 75 09 e8 6a d4 2d fe 31 db eb ca e8 61 d4 2d fe c6 05 ca 7c 75 05 01 31 db 48 c7 c7 d1 d9 40 88 31 c0 e8 0a 6b 00 fe <0f> 0b eb aa 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 67 fe ff ff 4c RSP: 0018:ffff88809491f680 EFLAGS: 00010246 RAX: cf6ab369a4203a00 RBX: 0000000000000000 RCX: ffff8880a15485c0 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: ffff88809491f6b8 R08: ffffffff815cc074 R09: ffffed1015d66120 R10: ffffed1015d66120 R11: 0000000000000000 R12: ffff8880a886aa04 R13: 0000000000008001 R14: 0000000000008100 R15: 1ffff11012923ed0 sock_wfree+0xf5/0x140 net/core/sock.c:1967 sctp_wfree+0x380/0x6d0 net/sctp/socket.c:8998 skb_release_head_state+0x100/0x210 net/core/skbuff.c:652 skb_release_all net/core/skbuff.c:663 [inline] __kfree_skb+0x25/0x170 net/core/skbuff.c:679 consume_skb+0x6b/0xb0 net/core/skbuff.c:838 sctp_chunk_destroy net/sctp/sm_make_chunk.c:1454 [inline] sctp_chunk_put+0x13d/0x1b0 net/sctp/sm_make_chunk.c:1481 sctp_chunk_free+0x59/0x60 net/sctp/sm_make_chunk.c:1468 __sctp_outq_teardown+0x210/0xa30 net/sctp/outqueue.c:219 sctp_outq_free+0x15/0x20 net/sctp/outqueue.c:276 sctp_association_free+0x22d/0x7a0 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+0x3e98/0x5720 net/sctp/sm_sideeffect.c:1155 sctp_primitive_ABORT+0x99/0xd0 net/sctp/primitive.c:104 sctp_close+0x263/0x6f0 net/sctp/socket.c:1513 inet_release+0x165/0x1c0 net/ipv4/af_inet.c:427 __sock_release net/socket.c:590 [inline] sock_close+0xe1/0x260 net/socket.c:1268 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x5e8/0x2190 kernel/exit.c:817 do_group_exit+0x15c/0x2b0 kernel/exit.c:921 __do_sys_exit_group+0x17/0x20 kernel/exit.c:932 __se_sys_exit_group+0x14/0x20 kernel/exit.c:930 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:930 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x43f268 Code: Bad RIP value. RSP: 002b:00007ffc061ba9d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043f268 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004bea68 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 000000002059aff8 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d01a0 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds..