[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.249' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 30.819695] [ 30.821324] ============================================ [ 30.826744] WARNING: possible recursive locking detected [ 30.832277] 4.14.243-syzkaller #0 Not tainted [ 30.836803] -------------------------------------------- [ 30.842223] syz-executor847/7985 is trying to acquire lock: [ 30.847901] (&type->i_mutex_dir_key#7){++++}, at: [] fuse_reverse_inval_entry+0x2a3/0x5e0 [ 30.857850] [ 30.857850] but task is already holding lock: [ 30.863793] (&type->i_mutex_dir_key#7){++++}, at: [] fuse_reverse_inval_entry+0x99/0x5e0 [ 30.873663] [ 30.873663] other info that might help us debug this: [ 30.880327] Possible unsafe locking scenario: [ 30.880327] [ 30.886356] CPU0 [ 30.888910] ---- [ 30.891465] lock(&type->i_mutex_dir_key#7); [ 30.895956] lock(&type->i_mutex_dir_key#7); [ 30.900425] [ 30.900425] *** DEADLOCK *** [ 30.900425] [ 30.906454] May be due to missing lock nesting notation [ 30.906454] [ 30.913360] 2 locks held by syz-executor847/7985: [ 30.918170] #0: (&fc->killsb){.+.+}, at: [] fuse_dev_do_write+0x1ec7/0x25c0 [ 30.926990] #1: (&type->i_mutex_dir_key#7){++++}, at: [] fuse_reverse_inval_entry+0x99/0x5e0 [ 30.937283] [ 30.937283] stack backtrace: [ 30.941756] CPU: 0 PID: 7985 Comm: syz-executor847 Not tainted 4.14.243-syzkaller #0 [ 30.949606] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.958931] Call Trace: [ 30.961580] dump_stack+0x1b2/0x281 [ 30.965184] __lock_acquire.cold+0x180/0x97c [ 30.969576] ? lock_downgrade+0x740/0x740 [ 30.973695] ? trace_hardirqs_on+0x10/0x10 [ 30.977906] ? ___d_drop+0x1ca/0x350 [ 30.981599] ? d_genocide_kill+0x140/0x140 [ 30.985806] ? do_raw_spin_unlock+0x164/0x220 [ 30.990273] ? d_genocide_kill+0x140/0x140 [ 30.994479] ? _raw_spin_unlock+0x29/0x40 [ 30.998597] ? d_walk+0x45e/0x840 [ 31.002022] ? d_invalidate+0x280/0x280 [ 31.005973] ? d_genocide_kill+0x140/0x140 [ 31.010183] lock_acquire+0x170/0x3f0 [ 31.014049] ? fuse_reverse_inval_entry+0x2a3/0x5e0 [ 31.019042] down_write+0x34/0x90 [ 31.022468] ? fuse_reverse_inval_entry+0x2a3/0x5e0 [ 31.027455] fuse_reverse_inval_entry+0x2a3/0x5e0 [ 31.032270] ? fuse_update_attributes+0xc0/0xc0 [ 31.036913] fuse_dev_do_write+0x1f22/0x25c0 [ 31.041299] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 31.046288] ? fuse_dev_read+0x1a0/0x1a0 [ 31.050328] ? lock_downgrade+0x740/0x740 [ 31.054450] ? wake_up_q+0x82/0xd0 [ 31.057966] ? drop_futex_key_refs+0x2e/0xa0 [ 31.062350] ? aa_file_perm+0x2dd/0xab0 [ 31.066302] ? lock_acquire+0x170/0x3f0 [ 31.070248] ? lock_downgrade+0x740/0x740 [ 31.074371] fuse_dev_write+0x125/0x1a0 [ 31.078318] ? fuse_dev_splice_write+0x920/0x920 [ 31.083062] ? fsnotify+0x974/0x11b0 [ 31.086749] ? iov_iter_init+0xa6/0x1c0 [ 31.090695] __vfs_write+0x44c/0x630 [ 31.094382] ? kernel_read+0x110/0x110 [ 31.098259] ? rw_verify_area+0xe1/0x2a0 [ 31.102296] vfs_write+0x17f/0x4d0 [ 31.105835] SyS_write+0xf2/0x210 [ 31.109273] ? SyS_read+0x210/0x210 [ 31.112875] ? do_syscall_64+0x4c/0x640 [ 31.116827] ? SyS_read+0x210/0x210 [ 31.120429] do_syscall_64+0x1d5/0x640 [ 31.124290] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.129470] RIP: 0033:0x4455e9 [ 31.132637] RSP: 002b:00007f89e31302f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 31.140321] RAX: ffffffffffffffda RBX: 00000000004ce4e0 RCX: 00000000004455e9 [ 31.147566] RDX: 000000000000002e RSI: 00000000200000c0 RDI: 0000000000000003 [ 31.154814] RBP: 000000000049e0d4 R08: 0000000000000000 R09: 0000000000000000 [ 31.162092] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049c0d0 [ 31.169375] R13: 65