Warning: Permanently added '10.128.0.116' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 31.268187] [ 31.269812] ============================================ [ 31.275234] WARNING: possible recursive locking detected [ 31.280656] 4.19.195-syzkaller #0 Not tainted [ 31.285118] -------------------------------------------- [ 31.290541] syz-executor685/8100 is trying to acquire lock: [ 31.296239] 00000000259e5d4d (&type->i_mutex_dir_key#7){++++}, at: fuse_reverse_inval_entry+0x2e1/0x660 [ 31.305754] [ 31.305754] but task is already holding lock: [ 31.311696] 0000000058a63160 (&type->i_mutex_dir_key#7){++++}, at: fuse_reverse_inval_entry+0xaa/0x660 [ 31.321120] [ 31.321120] other info that might help us debug this: [ 31.327760] Possible unsafe locking scenario: [ 31.327760] [ 31.333793] CPU0 [ 31.336347] ---- [ 31.338900] lock(&type->i_mutex_dir_key#7); [ 31.343368] lock(&type->i_mutex_dir_key#7); [ 31.347877] [ 31.347877] *** DEADLOCK *** [ 31.347877] [ 31.353938] May be due to missing lock nesting notation [ 31.353938] [ 31.360847] 2 locks held by syz-executor685/8100: [ 31.365703] #0: 0000000079719544 (&fc->killsb){.+.+}, at: fuse_dev_do_write+0x2343/0x2bc0 [ 31.374095] #1: 0000000058a63160 (&type->i_mutex_dir_key#7){++++}, at: fuse_reverse_inval_entry+0xaa/0x660 [ 31.384097] [ 31.384097] stack backtrace: [ 31.388576] CPU: 0 PID: 8100 Comm: syz-executor685 Not tainted 4.19.195-syzkaller #0 [ 31.396433] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.405766] Call Trace: [ 31.408338] dump_stack+0x1fc/0x2ef [ 31.411962] __lock_acquire.cold+0x121/0x57e [ 31.416353] ? mark_held_locks+0xf0/0xf0 [ 31.420388] ? lock_downgrade+0x720/0x720 [ 31.424513] ? lock_acquire+0x170/0x3c0 [ 31.428471] ? d_walk+0x310/0x990 [ 31.431904] ? check_preemption_disabled+0x41/0x280 [ 31.436893] ? do_raw_spin_unlock+0x171/0x230 [ 31.441365] ? _raw_spin_unlock+0x29/0x40 [ 31.445510] ? d_walk+0x526/0x990 [ 31.449026] ? __x32_compat_sys_ppoll+0x150/0x150 [ 31.453876] lock_acquire+0x170/0x3c0 [ 31.457691] ? fuse_reverse_inval_entry+0x2e1/0x660 [ 31.462726] down_write+0x34/0x90 [ 31.466215] ? fuse_reverse_inval_entry+0x2e1/0x660 [ 31.471211] fuse_reverse_inval_entry+0x2e1/0x660 [ 31.476030] ? fuse_update_attributes+0xc0/0xc0 [ 31.480706] ? fuse_dev_do_write+0x2343/0x2bc0 [ 31.485266] fuse_dev_do_write+0x239e/0x2bc0 [ 31.489656] ? futex_wait_queue_me+0x404/0x5e0 [ 31.494213] ? mark_held_locks+0xf0/0xf0 [ 31.498247] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 31.503322] ? fuse_dev_read+0x1f0/0x1f0 [ 31.507352] ? futex_wait+0x48e/0x610 [ 31.511127] ? lock_downgrade+0x720/0x720 [ 31.515264] ? check_preemption_disabled+0x41/0x280 [ 31.520268] ? check_preemption_disabled+0x41/0x280 [ 31.525265] ? aa_file_perm+0x417/0xd20 [ 31.529215] fuse_dev_write+0x153/0x1e0 [ 31.533165] ? fuse_dev_splice_write+0xa00/0xa00 [ 31.537890] ? do_futex+0x171/0x1880 [ 31.541582] ? iov_iter_init+0xb8/0x1d0 [ 31.545540] __vfs_write+0x51b/0x770 [ 31.549227] ? kernel_read+0x110/0x110 [ 31.553107] ? security_file_permission+0x1c0/0x220 [ 31.558098] vfs_write+0x1f3/0x540 [ 31.561613] ksys_write+0x12b/0x2a0 [ 31.565218] ? __ia32_sys_read+0xb0/0xb0 [ 31.569253] ? trace_hardirqs_off_caller+0x6e/0x210 [ 31.574244] ? do_syscall_64+0x21/0x620 [ 31.578189] do_syscall_64+0xf9/0x620 [ 31.581965] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.587126] RIP: 0033:0x4455e9 [ 31.590293] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 14 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 [ 31.609184] RSP: 002b:00007f14020992f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 31.616960] RAX: ffffffffffff