[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 69.124367][ T26] audit: type=1800 audit(1562640851.432:25): pid=8987 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 69.169497][ T26] audit: type=1800 audit(1562640851.432:26): pid=8987 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 69.199459][ T26] audit: type=1800 audit(1562640851.442:27): pid=8987 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] 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 '10.128.15.210' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 81.078256][ T9141] [ 81.080633][ T9141] ====================================================== [ 81.087636][ T9141] WARNING: possible circular locking dependency detected [ 81.094646][ T9141] 5.2.0-next-20190708 #33 Not tainted [ 81.099995][ T9141] ------------------------------------------------------ [ 81.106999][ T9141] syz-executor795/9141 is trying to acquire lock: [ 81.113393][ T9141] 000000002b57d3ab (&rp->fetch_lock){+.+.}, at: mon_bin_vma_fault+0x73/0x2d0 [ 81.122151][ T9141] [ 81.122151][ T9141] but task is already holding lock: [ 81.129505][ T9141] 0000000098497b51 (&mm->mmap_sem#2){++++}, at: __mm_populate+0x270/0x380 [ 81.138007][ T9141] [ 81.138007][ T9141] which lock already depends on the new lock. [ 81.138007][ T9141] [ 81.148422][ T9141] [ 81.148422][ T9141] the existing dependency chain (in reverse order) is: [ 81.157460][ T9141] [ 81.157460][ T9141] -> #1 (&mm->mmap_sem#2){++++}: [ 81.164613][ T9141] __might_fault+0x15e/0x1e0 [ 81.169714][ T9141] _copy_to_user+0x30/0x160 [ 81.174721][ T9141] mon_bin_read+0x329/0x640 [ 81.179731][ T9141] do_iter_read+0x4a4/0x660 [ 81.184756][ T9141] vfs_readv+0xf0/0x160 [ 81.189432][ T9141] do_preadv+0x1c4/0x280 [ 81.194174][ T9141] __x64_sys_preadv+0x9a/0xf0 [ 81.205318][ T9141] do_syscall_64+0xfd/0x6a0 [ 81.210340][ T9141] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 81.216735][ T9141] [ 81.216735][ T9141] -> #0 (&rp->fetch_lock){+.+.}: [ 81.223850][ T9141] __lock_acquire+0x25a9/0x4c30 [ 81.229216][ T9141] lock_acquire+0x190/0x410 [ 81.234241][ T9141] __mutex_lock+0xf7/0x1340 [ 81.239253][ T9141] mutex_lock_nested+0x16/0x20 [ 81.244723][ T9141] mon_bin_vma_fault+0x73/0x2d0 [ 81.250106][ T9141] __do_fault+0x111/0x540 [ 81.254992][ T9141] __handle_mm_fault+0xd41/0x3f20 [ 81.260531][ T9141] handle_mm_fault+0x1b5/0x6b0 [ 81.266872][ T9141] __get_user_pages+0x7d4/0x1b30 [ 81.272326][ T9141] populate_vma_page_range+0x20d/0x2a0 [ 81.278388][ T9141] __mm_populate+0x204/0x380 [ 81.283512][ T9141] vm_mmap_pgoff+0x213/0x230 [ 81.295786][ T9141] ksys_mmap_pgoff+0x4aa/0x630 [ 81.301065][ T9141] __x64_sys_mmap+0xe9/0x1b0 [ 81.306266][ T9141] do_syscall_64+0xfd/0x6a0 [ 81.311386][ T9141] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 81.317782][ T9141] [ 81.317782][ T9141] other info that might help us debug this: [ 81.317782][ T9141] [ 81.328001][ T9141] Possible unsafe locking scenario: [ 81.328001][ T9141] [ 81.335460][ T9141] CPU0 CPU1 [ 81.340818][ T9141] ---- ---- [ 81.346165][ T9141] lock(&mm->mmap_sem#2); [ 81.350561][ T9141] lock(&rp->fetch_lock); [ 81.357476][ T9141] lock(&mm->mmap_sem#2); [ 81.364490][ T9141] lock(&rp->fetch_lock); [ 81.368891][ T9141] [ 81.368891][ T9141] *** DEADLOCK *** [ 81.368891][ T9141] [ 81.377341][ T9141] 1 lock held by syz-executor795/9141: [ 81.382781][ T9141] #0: 0000000098497b51 (&mm->mmap_sem#2){++++}, at: __mm_populate+0x270/0x380 [ 81.391748][ T9141] [ 81.391748][ T9141] stack backtrace: [ 81.397666][ T9141] CPU: 0 PID: 9141 Comm: syz-executor795 Not tainted 5.2.0-next-20190708 #33 [ 81.406410][ T9141] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 81.416458][ T9141] Call Trace: [ 81.419764][ T9141] dump_stack+0x172/0x1f0 [ 81.424110][ T9141] print_circular_bug.cold+0x163/0x172 [ 81.429566][ T9141] check_noncircular+0x345/0x3e0 [ 81.434586][ T9141] ? print_circular_bug+0x200/0x200 [ 81.439993][ T9141] ? __lockdep_reset_lock+0x450/0x450 [ 81.445467][ T9141] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 81.452110][ T9141] ? find_first_zero_bit+0x9a/0xc0 [ 81.457218][ T9141] __lock_acquire+0x25a9/0x4c30 [ 81.462069][ T9141] ? stack_depot_save+0x25a/0x45c [ 81.467084][ T9141] ? mark_held_locks+0xf0/0xf0 [ 81.471871][ T9141] lock_acquire+0x190/0x410 [ 81.476361][ T9141] ? mon_bin_vma_fault+0x73/0x2d0 [ 81.481381][ T9141] ? mon_bin_vma_fault+0x73/0x2d0 [ 81.486425][ T9141] __mutex_lock+0xf7/0x1340 [ 81.491197][ T9141] ? mon_bin_vma_fault+0x73/0x2d0 [ 81.496234][ T9141] ? __kasan_check_read+0x11/0x20 [ 81.501260][ T9141] ? mon_bin_vma_fault+0x73/0x2d0 [ 81.506272][ T9141] ? mutex_lock_io_nested+0x11d0/0x11d0 [ 81.511840][ T9141] ? rcu_read_lock_sched_held+0x110/0x130 [ 81.517550][ T9141] ? kmem_cache_alloc+0x364/0x710 [ 81.522562][ T9141] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 81.528881][ T9141] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 81.535135][ T9141] mutex_lock_nested+0x16/0x20 [ 81.539923][ T9141] ? mutex_lock_nested+0x16/0x20 [ 81.544876][ T9141] mon_bin_vma_fault+0x73/0x2d0 [ 81.549727][ T9141] __do_fault+0x111/0x540 [ 81.554070][ T9141] ? mem_cgroup_try_charge_delay+0x6c/0xa0 [ 81.559906][ T9141] __handle_mm_fault+0xd41/0x3f20 [ 81.564937][ T9141] ? vmf_insert_mixed_mkwrite+0x40/0x40 [ 81.570497][ T9141] ? __kasan_check_read+0x11/0x20 [ 81.575523][ T9141] handle_mm_fault+0x1b5/0x6b0 [ 81.580294][ T9141] __get_user_pages+0x7d4/0x1b30 [ 81.585231][ T9141] ? mark_held_locks+0xf0/0xf0 [ 81.590002][ T9141] ? follow_page_mask+0x19b0/0x19b0 [ 81.595186][ T9141] ? __mm_populate+0x270/0x380 [ 81.599938][ T9141] ? memset+0x32/0x40 [ 81.603905][ T9141] populate_vma_page_range+0x20d/0x2a0 [ 81.609368][ T9141] __mm_populate+0x204/0x380 [ 81.614089][ T9141] ? populate_vma_page_range+0x2a0/0x2a0 [ 81.619714][ T9141] ? __kasan_check_read+0x11/0x20 [ 81.624747][ T9141] vm_mmap_pgoff+0x213/0x230 [ 81.629332][ T9141] ? vma_is_stack_for_current+0xd0/0xd0 [ 81.634875][ T9141] ? ksys_dup3+0x3e0/0x3e0 [ 81.639315][ T9141] ksys_mmap_pgoff+0x4aa/0x630 [ 81.644311][ T9141] ? find_mergeable_anon_vma+0x2e0/0x2e0 [ 81.659549][ T9141] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 81.669680][ T9141] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 81.683469][ T9141] ? do_syscall_64+0x26/0x6a0 [ 81.689011][ T9141] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 81.704767][ T9141] __x64_sys_mmap+0xe9/0x1b0 [ 81.714328][ T9141] do_syscall_64+0xfd/0x6a0 [ 81.723734][ T9141] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 81.736824][ T9141] RIP: 0033:0x4497f9 [ 81.749474][ T9141] Code: e8 ec b9 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 ab d6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 81.788994][ T9141] RSP: 002b:00007f37e61edcd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 [ 81.801712][ T9141] RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 00000000004497f9 [ 81.812356][ T9141] RDX: 0000000000000002 RSI: 0000000000400000 RDI: 0000000020a05000 [ 81.821101][ T9141] RBP: 00000000006dac30 R08: 0000000000000005 R09: 0000000000000000 [ 81.830131][ T9141] R10: 0000000000008012 R11: 0000000000000246 R12: 00000000006dac3c [ 81.838103][ T9141] R13: 00007ffcd13a161f R14: 00007f37e61ee9c0 R15: 20c49ba5e353f7cf