Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.12' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 33.041103] hrtimer: interrupt took 45419 ns [ 33.132060] overlayfs: './bus' not a directory [ 33.134070] overlayfs: './bus' not a directory executing program executing program [ 33.306490] [ 33.308222] ====================================================== [ 33.314533] WARNING: possible circular locking dependency detected [ 33.320846] 4.19.196-syzkaller #0 Not tainted [ 33.325331] ------------------------------------------------------ [ 33.331641] syz-executor045/8131 is trying to acquire lock: [ 33.337379] 00000000795e39a4 (sb_writers#3){.+.+}, at: mnt_want_write+0x3a/0xb0 [ 33.344843] [ 33.344843] but task is already holding lock: executing program executing program [ 33.350814] 00000000bcf1a620 (&ovl_i_mutex_dir_key[depth]){++++}, at: path_openat+0x1071/0x2df0 [ 33.360100] [ 33.360100] which lock already depends on the new lock. [ 33.360100] [ 33.368414] [ 33.368414] the existing dependency chain (in reverse order) is: [ 33.376032] [ 33.376032] -> #3 (&ovl_i_mutex_dir_key[depth]){++++}: [ 33.382806] path_openat+0x17ec/0x2df0 [ 33.387212] do_filp_open+0x18c/0x3f0 [ 33.391538] do_open_execat+0x11d/0x5b0 [ 33.396030] __do_execve_file+0x1a8b/0x2360 [ 33.400866] do_execve+0x35/0x50 executing program [ 33.404749] __x64_sys_execve+0x7c/0xa0 [ 33.409415] do_syscall_64+0xf9/0x620 [ 33.413735] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.419433] [ 33.419433] -> #2 (&sig->cred_guard_mutex){+.+.}: [ 33.425773] proc_pid_personality+0x4a/0x170 [ 33.426979] syz-executor045 (8136) used greatest stack depth: 23896 bytes left [ 33.430693] proc_single_show+0xeb/0x170 [ 33.430705] seq_read+0x4be/0x1160 [ 33.430718] do_iter_read+0x471/0x630 [ 33.450972] vfs_readv+0xe5/0x150 executing program [ 33.454950] __x64_sys_preadv+0x22b/0x310 [ 33.459620] do_syscall_64+0xf9/0x620 [ 33.463953] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.469853] [ 33.469853] -> #1 (&p->lock){+.+.}: [ 33.474972] seq_read+0x6b/0x1160 [ 33.478947] proc_reg_read+0x1bd/0x2d0 [ 33.483364] do_iter_read+0x471/0x630 [ 33.487686] vfs_readv+0xe5/0x150 [ 33.491658] default_file_splice_read+0x457/0xa00 [ 33.497021] do_splice_to+0x10e/0x160 [ 33.501342] splice_direct_to_actor+0x2b9/0x8d0 [ 33.506527] do_splice_direct+0x1a7/0x270 [ 33.511190] do_sendfile+0x550/0xc30 [ 33.515418] __se_sys_sendfile64+0x147/0x160 [ 33.520331] do_syscall_64+0xf9/0x620 [ 33.524635] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.530320] [ 33.530320] -> #0 (sb_writers#3){.+.+}: [ 33.535759] __sb_start_write+0x6e/0x2a0 [ 33.540322] mnt_want_write+0x3a/0xb0 [ 33.544622] ovl_create_object+0x96/0x290 [ 33.549269] lookup_open+0x893/0x1a20 [ 33.553567] path_openat+0x1094/0x2df0 [ 33.558015] do_filp_open+0x18c/0x3f0 [ 33.562327] do_sys_open+0x3b3/0x520 [ 33.566544] do_syscall_64+0xf9/0x620 [ 33.570848] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.576528] [ 33.576528] other info that might help us debug this: [ 33.576528] [ 33.584649] Chain exists of: [ 33.584649] sb_writers#3 --> &sig->cred_guard_mutex --> &ovl_i_mutex_dir_key[depth] [ 33.584649] [ 33.597043] Possible unsafe locking scenario: [ 33.597043] [ 33.603099] CPU0 CPU1 [ 33.607741] ---- ---- [ 33.612390] lock(&ovl_i_mutex_dir_key[depth]); [ 33.617123] lock(&sig->cred_guard_mutex); [ 33.623941] lock(&ovl_i_mutex_dir_key[depth]); [ 33.631188] lock(sb_writers#3); [ 33.634619] [ 33.634619] *** DEADLOCK *** [ 33.634619] [ 33.640662] 2 locks held by syz-executor045/8131: [ 33.645476] #0: 000000004169a01a (sb_writers#11){.+.+}, at: mnt_want_write+0x3a/0xb0 [ 33.653440] #1: 00000000bcf1a620 (&ovl_i_mutex_dir_key[depth]){++++}, at: path_openat+0x1071/0x2df0 [ 33.662709] [ 33.662709] stack backtrace: [ 33.667277] CPU: 1 PID: 8131 Comm: syz-executor045 Not tainted 4.19.196-syzkaller #0 [ 33.675144] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.684477] Call Trace: [ 33.687056] dump_stack+0x1fc/0x2ef [ 33.690671] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 33.696460] __lock_acquire+0x30c9/0x3ff0 [ 33.700589] ? do_raw_spin_unlock+0x171/0x230 [ 33.705063] ? mark_held_locks+0xf0/0xf0 [ 33.709111] ? ovl_lookup+0x379/0x1a00 [ 33.712993] lock_acquire+0x170/0x3c0 [ 33.716808] ? mnt_want_write+0x3a/0xb0 [ 33.720767] __sb_start_write+0x6e/0x2a0 [ 33.724810] ? mnt_want_write+0x3a/0xb0 [ 33.728766] mnt_want_write+0x3a/0xb0 [ 33.732551] ovl_create_object+0x96/0x290 [ 33.736680] ? ovl_create_or_link+0x1270/0x1270 [ 33.741331] ? revert_creds+0x326/0x450 [ 33.745287] ? security_inode_permission+0xc5/0xf0 [ 33.750228] ? inode_permission.part.0+0x10c/0x450 [ 33.755135] ? ovl_symlink+0x30/0x30 [ 33.758828] lookup_open+0x893/0x1a20 [ 33.762612] ? vfs_mkdir+0x7a0/0x7a0 [ 33.766317] ? check_preemption_disabled+0x41/0x280 [ 33.771750] path_openat+0x1094/0x2df0 [ 33.775641] ? path_lookupat+0x8d0/0x8d0 [ 33.779769] ? mark_held_locks+0xa6/0xf0 [ 33.783807] do_filp_open+0x18c/0x3f0 [ 33.787590] ? may_open_dev+0xf0/0xf0 [ 33.791372] ? lock_downgrade+0x720/0x720 [ 33.795507] ? __alloc_fd+0x102/0x570 [ 33.799298] ? lock_is_held_type+0x17a/0x210 [ 33.803686] ? do_raw_spin_unlock+0x171/0x230 [ 33.808171] ? _raw_spin_unlock+0x29/0x40 [ 33.812299] ? __alloc_fd+0x28d/0x570 [ 33.816077] do_sys_open+0x3b3/0x520 [ 33.819772] ? filp_open+0x70/0x70 [ 33.823293] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 33.828641] ? trace_hardirqs_off_caller+0x6e/0x210 [ 33.833656] ? do_syscall_64+0x21/0x620 [ 33.837957] do_syscall_64+0xf9/0x620 [ 33.841749] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.846918] RIP: 0033:0x4463a9 [ 33.850091] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 90 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 [ 33.868968] RSP: 002b:00007fe5eede0278 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 33.876652] RAX: ffffffffffffffda RBX: 00000000004cb4e0 RCX: 00000000004463a9 [ 33.883897] RDX: 0000000000000000 RSI: 00000000001612c2 RDI: 0000000020000200 [ 33.891180] RBP: 000000000049b0a8 R08: 0000000000000000 R09: 0000000000000000 [ 33.898430] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcaf11efae executing program executing program executing program executing program [ 33.905677] R13: 0073656369766564 R14: 6c616e6f73726570 R15: 00000000004cb4e8 executing program executing program executing program executing program executing program executing program executing program executing program [ 34.020767] syz-executor045 (8153) used greatest stack depth: 23160 bytes left 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 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 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 36.246652] syz-executor045 (8448) used greatest stack depth: 23144 bytes left 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 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 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 executing program executing program executing program executing program executing program executing program [ 38.605457] syz-executor045 (8762) used greatest stack depth: 23024 bytes left 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 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 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 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 [ 41.322935] syz-executor045 (9119) used greatest stack depth: 22976 bytes left 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 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 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