[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 65.992252][ T27] audit: type=1800 audit(1562164549.373:25): pid=8813 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 66.035330][ T27] audit: type=1800 audit(1562164549.373:26): pid=8813 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 66.080892][ T27] audit: type=1800 audit(1562164549.373:27): pid=8813 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 '10.128.0.196' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 78.062415][ T8969] [ 78.064777][ T8969] ====================================================== [ 78.071773][ T8969] WARNING: possible circular locking dependency detected [ 78.078772][ T8969] 5.2.0-rc7+ #47 Not tainted [ 78.083336][ T8969] ------------------------------------------------------ [ 78.090330][ T8969] syz-executor536/8969 is trying to acquire lock: [ 78.096716][ T8969] 00000000c8fdb9d9 (&rp->fetch_lock){+.+.}, at: mon_bin_vma_fault+0x73/0x2d0 [ 78.105466][ T8969] [ 78.105466][ T8969] but task is already holding lock: [ 78.112814][ T8969] 000000005b0afa3c (&mm->mmap_sem#2){++++}, at: __mm_populate+0x270/0x380 [ 78.121432][ T8969] [ 78.121432][ T8969] which lock already depends on the new lock. [ 78.121432][ T8969] [ 78.131830][ T8969] [ 78.131830][ T8969] the existing dependency chain (in reverse order) is: [ 78.140825][ T8969] [ 78.140825][ T8969] -> #1 (&mm->mmap_sem#2){++++}: [ 78.147961][ T8969] __might_fault+0x15e/0x1e0 [ 78.153062][ T8969] _copy_to_user+0x30/0x120 [ 78.158083][ T8969] mon_bin_read+0x329/0x640 [ 78.163096][ T8969] do_iter_read+0x4a4/0x660 [ 78.168094][ T8969] vfs_readv+0xf0/0x160 [ 78.172756][ T8969] do_preadv+0x1c4/0x280 [ 78.177494][ T8969] __x64_sys_preadv+0x9a/0xf0 [ 78.182677][ T8969] do_syscall_64+0xfd/0x680 [ 78.187697][ T8969] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 78.194090][ T8969] [ 78.194090][ T8969] -> #0 (&rp->fetch_lock){+.+.}: [ 78.201187][ T8969] lock_acquire+0x16f/0x3f0 [ 78.206218][ T8969] __mutex_lock+0xf7/0x1310 [ 78.211222][ T8969] mutex_lock_nested+0x16/0x20 [ 78.216514][ T8969] mon_bin_vma_fault+0x73/0x2d0 [ 78.221871][ T8969] __do_fault+0x111/0x4d0 [ 78.226707][ T8969] __handle_mm_fault+0xf67/0x3eb0 [ 78.232257][ T8969] handle_mm_fault+0x3b7/0xa90 [ 78.237528][ T8969] __get_user_pages+0x7b6/0x1a40 [ 78.242966][ T8969] populate_vma_page_range+0x20d/0x2a0 [ 78.248942][ T8969] __mm_populate+0x204/0x380 [ 78.254035][ T8969] vm_mmap_pgoff+0x213/0x230 [ 78.259129][ T8969] ksys_mmap_pgoff+0x4aa/0x630 [ 78.264391][ T8969] __x64_sys_mmap+0xe9/0x1b0 [ 78.269482][ T8969] do_syscall_64+0xfd/0x680 [ 78.274487][ T8969] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 78.280870][ T8969] [ 78.280870][ T8969] other info that might help us debug this: [ 78.280870][ T8969] [ 78.291074][ T8969] Possible unsafe locking scenario: [ 78.291074][ T8969] [ 78.298500][ T8969] CPU0 CPU1 [ 78.303847][ T8969] ---- ---- [ 78.309187][ T8969] lock(&mm->mmap_sem#2); [ 78.313586][ T8969] lock(&rp->fetch_lock); [ 78.320491][ T8969] lock(&mm->mmap_sem#2); [ 78.327403][ T8969] lock(&rp->fetch_lock); [ 78.331797][ T8969] [ 78.331797][ T8969] *** DEADLOCK *** [ 78.331797][ T8969] [ 78.339924][ T8969] 1 lock held by syz-executor536/8969: [ 78.345356][ T8969] #0: 000000005b0afa3c (&mm->mmap_sem#2){++++}, at: __mm_populate+0x270/0x380 [ 78.354280][ T8969] [ 78.354280][ T8969] stack backtrace: [ 78.360154][ T8969] CPU: 1 PID: 8969 Comm: syz-executor536 Not tainted 5.2.0-rc7+ #47 [ 78.368103][ T8969] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 78.378162][ T8969] Call Trace: [ 78.381448][ T8969] dump_stack+0x172/0x1f0 [ 78.385758][ T8969] print_circular_bug.cold+0x1cc/0x28f [ 78.391200][ T8969] __lock_acquire+0x3755/0x5490 [ 78.396031][ T8969] ? lockdep_hardirqs_on+0x418/0x5d0 [ 78.401291][ T8969] ? mark_held_locks+0xf0/0xf0 [ 78.406052][ T8969] ? save_stack+0x5c/0x90 [ 78.410358][ T8969] ? save_stack+0x23/0x90 [ 78.414701][ T8969] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 78.420492][ T8969] ? kasan_slab_alloc+0xf/0x20 [ 78.425244][ T8969] ? kmem_cache_alloc+0x11a/0x6f0 [ 78.430265][ T8969] ? pte_alloc_one+0x6d/0x1a0 [ 78.434940][ T8969] ? __handle_mm_fault+0xf67/0x3eb0 [ 78.440341][ T8969] lock_acquire+0x16f/0x3f0 [ 78.444826][ T8969] ? mon_bin_vma_fault+0x73/0x2d0 [ 78.449835][ T8969] ? mon_bin_vma_fault+0x73/0x2d0 [ 78.454860][ T8969] __mutex_lock+0xf7/0x1310 [ 78.459349][ T8969] ? mon_bin_vma_fault+0x73/0x2d0 [ 78.464358][ T8969] ? fs_reclaim_acquire.part.0+0x30/0x30 [ 78.469973][ T8969] ? mon_bin_vma_fault+0x73/0x2d0 [ 78.474985][ T8969] ? mutex_trylock+0x1e0/0x1e0 [ 78.479757][ T8969] ? ptlock_alloc+0x20/0x70 [ 78.484268][ T8969] ? rcu_read_lock_sched_held+0x110/0x130 [ 78.489965][ T8969] ? kmem_cache_alloc+0x32b/0x6f0 [ 78.494966][ T8969] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 78.501199][ T8969] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 78.507429][ T8969] mutex_lock_nested+0x16/0x20 [ 78.512195][ T8969] ? mutex_lock_nested+0x16/0x20 [ 78.517122][ T8969] mon_bin_vma_fault+0x73/0x2d0 [ 78.521962][ T8969] __do_fault+0x111/0x4d0 [ 78.526283][ T8969] ? mem_cgroup_try_charge_delay+0x6c/0xa0 [ 78.532105][ T8969] __handle_mm_fault+0xf67/0x3eb0 [ 78.537125][ T8969] ? vmf_insert_mixed_mkwrite+0x40/0x40 [ 78.542654][ T8969] ? find_held_lock+0x35/0x130 [ 78.547412][ T8969] ? handle_mm_fault+0x292/0xa90 [ 78.552328][ T8969] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 78.558548][ T8969] ? kasan_check_read+0x11/0x20 [ 78.563379][ T8969] handle_mm_fault+0x3b7/0xa90 [ 78.568122][ T8969] __get_user_pages+0x7b6/0x1a40 [ 78.573058][ T8969] ? follow_page_mask+0x19a0/0x19a0 [ 78.578237][ T8969] ? vma_set_page_prot+0x18c/0x240 [ 78.583333][ T8969] ? memset+0x32/0x40 [ 78.587310][ T8969] populate_vma_page_range+0x20d/0x2a0 [ 78.592765][ T8969] __mm_populate+0x204/0x380 [ 78.597367][ T8969] ? populate_vma_page_range+0x2a0/0x2a0 [ 78.602982][ T8969] ? kasan_check_write+0x14/0x20 [ 78.607906][ T8969] vm_mmap_pgoff+0x213/0x230 [ 78.612480][ T8969] ? vma_is_stack_for_current+0xd0/0xd0 [ 78.618006][ T8969] ? ksys_dup3+0x3e0/0x3e0 [ 78.622416][ T8969] ksys_mmap_pgoff+0x4aa/0x630 [ 78.627162][ T8969] ? find_mergeable_anon_vma+0x2e0/0x2e0 [ 78.632771][ T8969] ? rcu_read_lock_sched_held+0x110/0x130 [ 78.638468][ T8969] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 78.643914][ T8969] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 78.649405][ T8969] ? do_syscall_64+0x26/0x680 [ 78.654072][ T8969] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 78.660129][ T8969] __x64_sys_mmap+0xe9/0x1b0 [ 78.664716][ T8969] do_syscall_64+0xfd/0x680 [ 78.669245][ T8969] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 78.675127][ T8969] RIP: 0033:0x44a6f9 [ 78.679019][ T8969] Code: e8 8c b5 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 2b cc fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 78.698616][ T8969] RSP: 002b:00007f90aa11bcd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 [ 78.707014][ T8969] RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 000000000044a6f9 [ 78.715757][ T8969] RDX: 0000000000000002 RSI: 0000000000400000 RDI: 0000000020a05000 [ 78.723722][ T8969] RBP: 00000000006dbc30 R08: 0000000000000005 R09: 0000000000000000 [ 78.731702][ T8969] R10: 0000000000008012 R11: 0000000000000246 R12: 00000000006dbc3c [ 78.739662][ T8969] R13: 00007ffcb8e9061f R14: 00007f90aa11c9c0 R15: 20c49ba5e353f7cf executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program