executing program executing program executing program executing program executing program syzkaller login: [ 23.424940] refcount_t: underflow; use-after-free. [ 23.425541] ------------[ cut here ]------------ [ 23.425986] WARNING: CPU: 3 PID: 3049 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 23.426789] Kernel panic - not syncing: panic_on_warn set ... [ 23.426789] [ 23.427839] CPU: 3 PID: 3049 Comm: syzkaller403583 Not tainted 4.14.0-rc5-next-20171018+ #8 [ 23.428567] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 23.429261] Call Trace: [ 23.429421] dump_stack+0x194/0x257 [ 23.429688] ? arch_local_irq_restore+0x53/0x53 [ 23.430091] ? vsnprintf+0x1ed/0x1900 [ 23.430414] panic+0x1e4/0x41c [ 23.430685] ? refcount_error_report+0x214/0x214 [ 23.431082] ? show_regs_print_info+0x65/0x65 [ 23.431470] ? __warn+0x1a9/0x1e0 [ 23.431767] ? refcount_sub_and_test+0x167/0x1b0 [ 23.432165] __warn+0x1c4/0x1e0 [ 23.432442] ? refcount_sub_and_test+0x167/0x1b0 [ 23.432855] report_bug+0x211/0x2d0 [ 23.433167] fixup_bug+0x40/0x90 [ 23.433453] do_trap+0x260/0x390 [ 23.433747] do_error_trap+0x120/0x390 [ 23.434116] ? vprintk_emit+0x49b/0x590 [ 23.434454] ? do_trap+0x390/0x390 [ 23.434797] ? refcount_sub_and_test+0x167/0x1b0 [ 23.435197] ? vprintk_emit+0x3ea/0x590 [ 23.435540] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 23.435949] do_invalid_op+0x1b/0x20 [ 23.436261] invalid_op+0x18/0x20 [ 23.436550] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 23.436987] RSP: 0018:ffff880039b369c8 EFLAGS: 00010282 [ 23.437440] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 23.438063] RDX: 0000000000000026 RSI: 1ffff10007366cf9 RDI: ffffed0007366d2d [ 23.438660] RBP: ffff880039b36a58 R08: 0000000000000001 R09: 0000000000000000 [ 23.439251] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10007366d3a [ 23.439845] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff88006aeda2fc [ 23.440462] ? refcount_sub_and_test+0x167/0x1b0 [ 23.440860] ? refcount_inc+0x50/0x50 [ 23.441177] ? sctp_outq_free+0x15/0x20 [ 23.441514] ? sctp_do_sm+0x271b/0x6a30 [ 23.441848] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 23.442278] ? sctp_close+0x3c6/0x980 [ 23.442597] ? inet_release+0xed/0x1c0 [ 23.442922] ? sock_release+0x8d/0x1e0 [ 23.443251] sctp_wfree+0x183/0x620 [ 23.443558] ? __sctp_write_space+0x910/0x910 [ 23.443935] skb_release_head_state+0x124/0x200 [ 23.444330] skb_release_all+0x15/0x60 [ 23.444656] consume_skb+0x153/0x490 [ 23.444963] ? sctp_chunk_put+0x99/0x420 [ 23.445311] ? alloc_skb_with_frags+0x750/0x750 [ 23.445702] ? sctp_chunk_hold+0x20/0x20 [ 23.446079] ? refcount_sub_and_test+0x115/0x1b0 [ 23.446479] ? refcount_inc+0x50/0x50 [ 23.446795] ? mark_held_locks+0xaf/0x100 [ 23.447143] ? sctp_datamsg_put+0x456/0x560 [ 23.447513] sctp_chunk_put+0x29c/0x420 [ 23.447847] ? sctp_chunk_hold+0x20/0x20 [ 23.448417] ? sctp_transport_dst_confirm+0x50/0x50 [ 23.448814] ? sctp_sched_fcfs_dequeue+0x198/0x290 [ 23.449228] ? sctp_sched_dequeue_common+0x5d0/0x5d0 [ 23.449663] sctp_chunk_free+0x53/0x60 [ 23.450030] __sctp_outq_teardown+0xa5b/0x1230 [ 23.450440] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 23.450890] ? print_irqtrace_events+0x270/0x270 [ 23.451310] ? noop_count+0x40/0x40 [ 23.451667] ? trace_hardirqs_off+0x10/0x10 [ 23.452031] ? __bfs+0xaa/0x750 [ 23.452309] ? __is_insn_slot_addr+0x1fc/0x330 [ 23.452698] ? check_noncircular+0x20/0x20 [ 23.453055] ? print_irqtrace_events+0x270/0x270 [ 23.453445] ? lock_release+0xa40/0xa40 [ 23.453777] ? bpf_prog_kallsyms_find+0xbd/0x440 [ 23.454185] ? lock_acquire+0x1d5/0x580 [ 23.454517] ? lock_acquire+0x1d5/0x580 [ 23.454847] ? lock_timer_base+0x1a3/0x2b0 [ 23.455612] ? find_held_lock+0x35/0x1d0 [ 23.455979] ? sock_def_wakeup+0x1f9/0x350 [ 23.456314] ? lock_downgrade+0x990/0x990 [ 23.456603] ? lock_release+0xa40/0xa40 [ 23.456902] sctp_outq_free+0x15/0x20 [ 23.457243] sctp_association_free+0x2d0/0x930 [ 23.457578] ? sctp_asconf_queue_teardown+0x700/0x700 [ 23.457985] ? sock_def_wakeup+0x222/0x350 [ 23.458316] ? sk_dst_check+0x560/0x560 [ 23.458602] ? sctp_association_put+0x74/0x2f0 [ 23.458936] ? sctp_association_hold+0x20/0x20 [ 23.459268] sctp_do_sm+0x271b/0x6a30 [ 23.459546] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 23.460002] ? print_irqtrace_events+0x270/0x270 [ 23.460359] ? __lock_acquire+0x6aa/0x3d50 [ 23.460656] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 23.461040] ? print_irqtrace_events+0x270/0x270 [ 23.461398] ? find_held_lock+0x35/0x1d0 [ 23.461677] ? skb_dequeue+0x12a/0x180 [ 23.461993] ? lock_downgrade+0x990/0x990 [ 23.462257] ? do_raw_spin_trylock+0x190/0x190 [ 23.462531] ? mark_held_locks+0xaf/0x100 [ 23.462782] ? trace_hardirqs_on+0xd/0x10 [ 23.463042] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 23.463318] sctp_close+0x3c6/0x980 [ 23.463541] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 23.463851] ? __lock_acquire+0x6aa/0x3d50 [ 23.464112] ? check_noncircular+0x20/0x20 [ 23.464363] ? check_noncircular+0x20/0x20 [ 23.464622] ? __lock_acquire+0x6aa/0x3d50 [ 23.464900] ? locks_remove_file+0x3fa/0x5a0 [ 23.465172] ? fcntl_setlk+0x10c0/0x10c0 [ 23.465421] ? __fsnotify_parent+0xb4/0x3a0 [ 23.465676] ? ip_mc_drop_socket+0x1ce/0x230 [ 23.466009] inet_release+0xed/0x1c0 [ 23.466332] sock_release+0x8d/0x1e0 [ 23.466647] ? sock_release+0x1e0/0x1e0 [ 23.466980] sock_close+0x16/0x20 [ 23.467278] __fput+0x327/0x7e0 [ 23.467561] ? fput+0x140/0x140 [ 23.467837] ? _raw_spin_unlock_irq+0x27/0x70 [ 23.468223] ____fput+0x15/0x20 [ 23.468499] task_work_run+0x199/0x270 [ 23.468833] ? task_work_cancel+0x210/0x210 [ 23.469201] ? __do_page_fault+0x3d6/0xd60 [ 23.469570] get_signal+0x1343/0x16d0 [ 23.470182] ? mm_fault_error+0x2c0/0x2c0 [ 23.470487] ? check_noncircular+0x20/0x20 [ 23.470848] ? ptrace_notify+0x130/0x130 [ 23.471189] ? check_noncircular+0x20/0x20 [ 23.471540] ? __do_page_fault+0xd60/0xd60 [ 23.471890] ? do_page_fault+0xee/0x720 [ 23.472213] ? lock_downgrade+0x990/0x990 [ 23.472561] ? __do_page_fault+0xd60/0xd60 [ 23.472914] ? do_raw_spin_trylock+0x190/0x190 [ 23.473300] ? check_noncircular+0x20/0x20 [ 23.473657] ? find_held_lock+0x35/0x1d0 [ 23.474057] ? retint_kernel+0x10/0x10 [ 23.474395] do_signal+0x94/0x1ee0 [ 23.474698] ? put_unused_fd+0x62/0x70 [ 23.475023] ? lock_downgrade+0x990/0x990 [ 23.475375] ? setup_sigcontext+0x7d0/0x7d0 [ 23.475738] ? do_raw_spin_trylock+0x190/0x190 [ 23.476160] ? __put_unused_fd+0x183/0x250 [ 23.476520] ? alloc_fdtable+0x280/0x280 [ 23.476860] ? cpumask_weight.constprop.1+0x48/0x48 [ 23.477282] ? _copy_to_user+0xa2/0xc0 [ 23.477616] ? _raw_spin_unlock+0x22/0x30 [ 23.477976] ? fput+0xd2/0x140 [ 23.478248] ? SYSC_accept4+0x4ec/0x850 [ 23.478585] ? exit_to_usermode_loop+0x8c/0x310 [ 23.478979] exit_to_usermode_loop+0x214/0x310 [ 23.479368] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 23.479826] ? __do_page_fault+0xd60/0xd60 [ 23.480187] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 23.480612] syscall_return_slowpath+0x42f/0x510 [ 23.481011] ? finish_task_switch+0x1f6/0x740 [ 23.481387] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 23.481815] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 23.482283] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 23.482735] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 23.483032] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 23.483311] RIP: 0033:0x43c7b9 [ 23.483499] RSP: 002b:00007fd2e135edb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000120 [ 23.483949] RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 000000000043c7b9 [ 23.484369] RDX: 0000000020137ffc RSI: 0000000020b53ff0 RDI: 0000000000000003 [ 23.484791] RBP: 0000000000000000 R08: 00007fd2e135f700 R09: 0000000000000000 [ 23.485214] R10: 0000000000080000 R11: 0000000000000206 R12: 0000000000000000 [ 23.485643] R13: 0000000000000000 R14: 00007fd2e135f9c0 R15: 00007fd2e135f700 [ 23.489953] Dumping ftrace buffer: [ 23.490265] (ftrace buffer empty) [ 23.490490] Kernel Offset: disabled [ 23.490711] Rebooting in 86400 seconds..