INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.52' (ECDSA) to the list of known hosts. syzkaller login: [ 29.255100] sctp: [Deprecated]: syzkaller286002 (pid 4480) Use of struct sctp_assoc_value in delayed_ack socket option. [ 29.255100] Use struct sctp_sack_info instead [ 29.270500] [ 29.272106] ====================================================== [ 29.278392] WARNING: possible circular locking dependency detected [ 29.284683] 4.17.0-rc1+ #12 Not tainted [ 29.288627] ------------------------------------------------------ [ 29.294919] syzkaller286002/4480 is trying to acquire lock: [ 29.300611] 0000000042c6ef50 (&mm->mmap_sem){++++}, at: __might_fault+0xfb/0x1e0 [ 29.308137] [ 29.308137] but task is already holding lock: [ 29.314082] 0000000036914416 (sk_lock-AF_INET6){+.+.}, at: sctp_setsockopt+0x33e/0x7000 [ 29.322209] [ 29.322209] which lock already depends on the new lock. [ 29.322209] [ 29.330500] [ 29.330500] the existing dependency chain (in reverse order) is: [ 29.338096] [ 29.338096] -> #1 (sk_lock-AF_INET6){+.+.}: [ 29.343883] lock_sock_nested+0xd0/0x120 [ 29.348456] tcp_mmap+0x1c7/0x14f0 [ 29.352496] sock_mmap+0x8e/0xc0 [ 29.356364] mmap_region+0xd13/0x1820 [ 29.360660] do_mmap+0xc79/0x11d0 [ 29.364612] vm_mmap_pgoff+0x1fb/0x2a0 [ 29.368995] ksys_mmap_pgoff+0x4c9/0x640 [ 29.373557] __x64_sys_mmap+0xe9/0x1b0 [ 29.377941] do_syscall_64+0x1b1/0x800 [ 29.382328] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 29.388013] [ 29.388013] -> #0 (&mm->mmap_sem){++++}: [ 29.393549] lock_acquire+0x1dc/0x520 [ 29.397846] __might_fault+0x155/0x1e0 [ 29.402232] _copy_from_user+0x30/0x150 [ 29.406716] sctp_setsockopt+0x287c/0x7000 [ 29.411457] sock_common_setsockopt+0x9a/0xe0 [ 29.416460] __sys_setsockopt+0x1bd/0x390 [ 29.421114] __x64_sys_setsockopt+0xbe/0x150 [ 29.426027] do_syscall_64+0x1b1/0x800 [ 29.430419] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 29.436098] [ 29.436098] other info that might help us debug this: [ 29.436098] [ 29.444216] Possible unsafe locking scenario: [ 29.444216] [ 29.450249] CPU0 CPU1 [ 29.454888] ---- ---- [ 29.459527] lock(sk_lock-AF_INET6); [ 29.463305] lock(&mm->mmap_sem); [ 29.469334] lock(sk_lock-AF_INET6); [ 29.475623] lock(&mm->mmap_sem); [ 29.479141] [ 29.479141] *** DEADLOCK *** [ 29.479141] [ 29.485177] 1 lock held by syzkaller286002/4480: [ 29.489903] #0: 0000000036914416 (sk_lock-AF_INET6){+.+.}, at: sctp_setsockopt+0x33e/0x7000 [ 29.498470] [ 29.498470] stack backtrace: [ 29.502946] CPU: 0 PID: 4480 Comm: syzkaller286002 Not tainted 4.17.0-rc1+ #12 [ 29.510281] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.519614] Call Trace: [ 29.522183] dump_stack+0x1b9/0x294 [ 29.525786] ? dump_stack_print_info.cold.2+0x52/0x52 [ 29.530955] ? print_lock+0xd1/0xd6 [ 29.534559] ? vprintk_func+0x81/0xe7 [ 29.538338] print_circular_bug.isra.36.cold.54+0x1bd/0x27d [ 29.544034] ? save_trace+0xe0/0x290 [ 29.547736] __lock_acquire+0x343e/0x5140 [ 29.551865] ? debug_check_no_locks_freed+0x310/0x310 [ 29.557033] ? console_unlock+0x82c/0x1100 [ 29.561245] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 29.566238] ? console_unlock+0xb37/0x1100 [ 29.570449] ? wake_up_klogd+0x100/0x100 [ 29.574484] ? mark_held_locks+0xc9/0x160 [ 29.578628] ? __down_trylock_console_sem+0xd3/0x200 [ 29.583709] ? vprintk_emit+0x694/0xdd0 [ 29.587662] ? vprintk_emit+0x694/0xdd0 [ 29.591623] ? vprintk_emit+0x3e5/0xdd0 [ 29.595575] ? graph_lock+0x170/0x170 [ 29.599353] ? console_unlock+0x1100/0x1100 [ 29.603652] lock_acquire+0x1dc/0x520 [ 29.607431] ? __might_fault+0xfb/0x1e0 [ 29.611383] ? lock_release+0xa10/0xa10 [ 29.615334] ? check_same_owner+0x320/0x320 [ 29.619630] ? vprintk_default+0x28/0x30 [ 29.623669] ? vprintk_func+0x81/0xe7 [ 29.627446] ? __might_sleep+0x95/0x190 [ 29.631396] __might_fault+0x155/0x1e0 [ 29.635259] ? __might_fault+0xfb/0x1e0 [ 29.639214] _copy_from_user+0x30/0x150 [ 29.643167] sctp_setsockopt+0x287c/0x7000 [ 29.647382] ? mark_held_locks+0xc9/0x160 [ 29.651503] ? page_add_new_anon_rmap+0x3ff/0x850 [ 29.656325] ? sctp_setsockopt_paddr_thresholds+0x560/0x560 [ 29.662020] ? find_held_lock+0x36/0x1c0 [ 29.666066] ? lock_downgrade+0x8e0/0x8e0 [ 29.670189] ? pudp_huge_clear_flush+0x230/0x230 [ 29.674921] ? kasan_check_read+0x11/0x20 [ 29.679047] ? do_raw_spin_unlock+0x9e/0x2e0 [ 29.683432] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 29.687998] ? kasan_check_write+0x14/0x20 [ 29.692213] ? do_raw_spin_lock+0xc1/0x200 [ 29.696429] ? _raw_spin_unlock+0x22/0x30 [ 29.700555] ? do_huge_pmd_anonymous_page+0x48d/0x1cc0 [ 29.705811] ? __thp_get_unmapped_area+0x180/0x180 [ 29.710717] ? debug_check_no_locks_freed+0x310/0x310 [ 29.715894] ? alloc_file+0x24/0x3e0 [ 29.719594] ? sock_alloc_file+0x1f3/0x4e0 [ 29.723804] ? __sys_socket+0x16f/0x250 [ 29.727754] ? do_syscall_64+0x1b1/0x800 [ 29.731792] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 29.737135] ? debug_mutex_init+0x1c/0x60 [ 29.741261] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 29.746251] ? graph_lock+0x170/0x170 [ 29.750041] ? pud_val+0x80/0xf0 [ 29.753383] ? pmd_val+0xf0/0xf0 [ 29.756729] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 29.762243] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 29.767755] ? __handle_mm_fault+0x93a/0x4310 [ 29.772227] ? vm_insert_mixed_mkwrite+0x40/0x40 [ 29.776964] ? graph_lock+0x170/0x170 [ 29.780738] ? graph_lock+0x170/0x170 [ 29.784513] ? find_held_lock+0x36/0x1c0 [ 29.788554] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 29.794067] ? __fget_light+0x2ef/0x430 [ 29.798025] ? fget_raw+0x20/0x20 [ 29.801458] ? lock_downgrade+0x8e0/0x8e0 [ 29.805582] ? handle_mm_fault+0x8c0/0xc70 [ 29.809795] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 29.815309] ? handle_mm_fault+0x55a/0xc70 [ 29.819523] sock_common_setsockopt+0x9a/0xe0 [ 29.824003] __sys_setsockopt+0x1bd/0x390 [ 29.828135] ? kernel_accept+0x310/0x310 [ 29.832175] ? mm_fault_error+0x380/0x380 [ 29.836305] ? __ia32_sys_fallocate+0xf0/0xf0 [ 29.840776] __x64_sys_setsockopt+0xbe/0x150 [ 29.845161] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 29.850152] do_syscall_64+0x1b1/0x800 [ 29.854021] ? syscall_slow_exit_work+0x4f0/0x4f0 [ 29.858842] ? syscall_return_slowpath+0x5c0/0x5c0 [ 29.863750] ? syscall_return_slowpath+0x30f/0x5c0 [ 29.868659] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 29.874173] ? retint_user+0x18/0x18 [ 29.877863] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 29.882687] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 29.887860] RIP: 0033:0x43fd09 [ 29.891034] RSP: 002b:00007fff1f570e58 EFLAGS: 00000217 ORIG_RAX: 0000000000000036 [ 29.898718] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fd09 [ 29.905966] RDX: 000000