./strace-static-x86_64 -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f ./syz-executor1692103820 <...> DUID 00:04:ac:03:58:10:d0:76:5c:28:30:a7:8a:8b:4a:a3:06:e2 forked to background, child pid 4644 [ 34.055739][ T4645] 8021q: adding VLAN 0 to HW filter on device bond0 [ 34.068857][ T4645] eql: remember to turn off Van-Jacobson compression on your slave devices Starting sshd: OK syzkaller Warning: Permanently added '10.128.1.45' (ECDSA) to the list of known hosts. execve("./syz-executor1692103820", ["./syz-executor1692103820"], 0x7fff70ea9b40 /* 10 vars */) = 0 brk(NULL) = 0x555557328000 brk(0x555557328c40) = 0x555557328c40 arch_prctl(ARCH_SET_FS, 0x555557328300) = 0 uname({sysname="Linux", nodename="syzkaller", ...}) = 0 readlink("/proc/self/exe", "/root/syz-executor1692103820", 4096) = 28 brk(0x555557349c40) = 0x555557349c40 brk(0x55555734a000) = 0x55555734a000 mprotect(0x7fa3d1672000, 16384, PROT_READ) = 0 mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000 mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000 mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000 mkdir("./file0", 000) = 0 mkdir("./file1", 000) = 0 mkdir("./bus", 000) = 0 mount(NULL, "./bus", "overlay", 0, "upperdir=./bus,workdir=./file1,lowerdir=./file0") = 0 chdir("./bus") = 0 creat("./bus", 000) = 3 syzkaller login: [ 56.708354][ T5069] [ 56.710696][ T5069] ============================================ [ 56.716823][ T5069] WARNING: possible recursive locking detected [ 56.722950][ T5069] 6.1.0-rc8-next-20221207-syzkaller #0 Not tainted [ 56.729426][ T5069] -------------------------------------------- [ 56.735559][ T5069] syz-executor169/5069 is trying to acquire lock: [ 56.741957][ T5069] ffff8880750fa480 (&ovl_i_mutex_key[depth]){+.+.}-{3:3}, at: ovl_fallocate+0x15c/0x270 [ 56.751803][ T5069] [ 56.751803][ T5069] but task is already holding lock: [ 56.759155][ T5069] ffff8880750fa480 (&ovl_i_mutex_key[depth]){+.+.}-{3:3}, at: ovl_fallocate+0x9f/0x270 [ 56.768804][ T5069] [ 56.768804][ T5069] other info that might help us debug this: [ 56.776843][ T5069] Possible unsafe locking scenario: [ 56.776843][ T5069] [ 56.784278][ T5069] CPU0 [ 56.787542][ T5069] ---- [ 56.790806][ T5069] lock(&ovl_i_mutex_key[depth]); [ 56.795902][ T5069] lock(&ovl_i_mutex_key[depth]); [ 56.800994][ T5069] [ 56.800994][ T5069] *** DEADLOCK *** [ 56.800994][ T5069] [ 56.809115][ T5069] May be due to missing lock nesting notation [ 56.809115][ T5069] [ 56.817415][ T5069] 2 locks held by syz-executor169/5069: [ 56.822951][ T5069] #0: ffff88802b1d6460 (sb_writers#9){.+.+}-{0:0}, at: __x64_sys_fallocate+0xd3/0x140 [ 56.832610][ T5069] #1: ffff8880750fa480 (&ovl_i_mutex_key[depth]){+.+.}-{3:3}, at: ovl_fallocate+0x9f/0x270 [ 56.842687][ T5069] [ 56.842687][ T5069] stack backtrace: [ 56.848552][ T5069] CPU: 1 PID: 5069 Comm: syz-executor169 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0 [ 56.858421][ T5069] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 [ 56.868458][ T5069] Call Trace: [ 56.871721][ T5069] [ 56.874634][ T5069] dump_stack_lvl+0xd1/0x138 [ 56.879213][ T5069] __lock_acquire.cold+0x116/0x3a7 [ 56.884321][ T5069] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 56.890288][ T5069] lock_acquire+0x1e3/0x630 [ 56.894774][ T5069] ? ovl_fallocate+0x15c/0x270 [ 56.899528][ T5069] ? lock_release+0x810/0x810 [ 56.904189][ T5069] ? cap_inode_need_killpriv+0x4c/0x60 [ 56.909641][ T5069] ? ovl_path_type+0xde/0x350 [ 56.914307][ T5069] down_write+0x94/0x220 [ 56.918541][ T5069] ? ovl_fallocate+0x15c/0x270 [ 56.923294][ T5069] ? down_write_killable+0x250/0x250 [ 56.928569][ T5069] ? ovl_real_fdget+0xb5/0x260 [ 56.933323][ T5069] ovl_fallocate+0x15c/0x270 [ 56.937903][ T5069] ? ovl_open+0x2e0/0x2e0 [ 56.942225][ T5069] ? ovl_open+0x2e0/0x2e0 [ 56.946550][ T5069] vfs_fallocate+0x48b/0xe00 [ 56.951133][ T5069] __x64_sys_fallocate+0xd3/0x140 [ 56.956150][ T5069] do_syscall_64+0x39/0xb0 [ 56.960555][ T5069] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 56.966437][ T5069] RIP: 0033:0x7fa3d1605c29 [ 56.970836][ T5069] Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 56.990424][ T5069] RSP: 002b:00007ffccc67e118 EFLAGS: 00000246 ORIG_RAX: 000000000000011d [ 56.998819][ T5069] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa3d1605c29 [ 57.006773][ T5069] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 [ 57.014726][ T5069] RBP: 00007fa3d15c9dd0 R08: 0000000000000000 R09: 0000000000000000 [ 57.022690][ T5069] R10: 00000000001000f4 R11: 0000000000000246 R12: 00007fa3d15c9e60 [ 57.030645][ T5069] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 57.038602][ T5069]