./strace-static-x86_64 -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f ./syz-executor318073634 <...> DUID 00:04:ae:1e:d5:49:b7:3c:3f:84:b3:e9:d7:e4:a5:00:02:90 forked to background, child pid 4669 [ 33.287041][ T4670] 8021q: adding VLAN 0 to HW filter on device bond0 [ 33.298706][ T4670] eql: remember to turn off Van-Jacobson compression on your slave devices Starting sshd: OK syzkaller Warning: Permanently added '10.128.0.139' (ECDSA) to the list of known hosts. execve("./syz-executor318073634", ["./syz-executor318073634"], 0x7fff8f69fe80 /* 10 vars */) = 0 brk(NULL) = 0x555555b51000 brk(0x555555b51c40) = 0x555555b51c40 arch_prctl(ARCH_SET_FS, 0x555555b51300) = 0 uname({sysname="Linux", nodename="syzkaller", ...}) = 0 set_tid_address(0x555555b515d0) = 5001 set_robust_list(0x555555b515e0, 24) = 0 rt_sigaction(SIGRTMIN, {sa_handler=0x7f15940a5f20, sa_mask=[], sa_flags=SA_RESTORER|SA_SIGINFO, sa_restorer=0x7f15940a65f0}, NULL, 8) = 0 rt_sigaction(SIGRT_1, {sa_handler=0x7f15940a5fc0, sa_mask=[], sa_flags=SA_RESTORER|SA_RESTART|SA_SIGINFO, sa_restorer=0x7f15940a65f0}, NULL, 8) = 0 rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0 prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0 readlink("/proc/self/exe", "/root/syz-executor318073634", 4096) = 27 brk(0x555555b72c40) = 0x555555b72c40 brk(0x555555b73000) = 0x555555b73000 mprotect(0x7f1594166000, 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 futex(0x7f159416c40c, FUTEX_WAKE_PRIVATE, 1000000) = 0 mmap(NULL, 135168, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f1594076000 mprotect(0x7f1594077000, 131072, PROT_READ|PROT_WRITE) = 0 clone(child_stack=0x7f15940963f0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID./strace-static-x86_64: Process 5002 attached , parent_tid=[5002], tls=0x7f1594096700, child_tidptr=0x7f15940969d0) = 5002 [pid 5002] set_robust_list(0x7f15940969e0, 24) = 0 [pid 5002] futex(0x7f159416c408, FUTEX_WAIT_PRIVATE, 0, NULL [pid 5001] futex(0x7f159416c408, FUTEX_WAKE_PRIVATE, 1000000) = 0 [pid 5002] <... futex resumed>) = -1 EAGAIN (Resource temporarily unavailable) [pid 5002] pipe2( [pid 5001] futex(0x7f159416c40c, FUTEX_WAIT_PRIVATE, 0, {tv_sec=0, tv_nsec=50000000} [pid 5002] <... pipe2 resumed>[3, 4], 0) = 0 [pid 5002] futex(0x7f159416c40c, FUTEX_WAKE_PRIVATE, 1000000) = 1 [pid 5001] <... futex resumed>) = 0 [pid 5001] futex(0x7f159416c408, FUTEX_WAKE_PRIVATE, 1000000 [pid 5002] pipe2( [pid 5001] <... futex resumed>) = 0 [pid 5001] futex(0x7f159416c40c, FUTEX_WAIT_PRIVATE, 0, {tv_sec=0, tv_nsec=50000000} [pid 5002] <... pipe2 resumed>[5, 6], O_EXCL|O_NONBLOCK) = 0 [pid 5002] futex(0x7f159416c40c, FUTEX_WAKE_PRIVATE, 1000000) = 1 [pid 5001] <... futex resumed>) = 0 [pid 5001] futex(0x7f159416c408, FUTEX_WAKE_PRIVATE, 1000000) = 0 [pid 5001] futex(0x7f159416c40c, FUTEX_WAIT_PRIVATE, 0, {tv_sec=0, tv_nsec=50000000} [pid 5002] openat(AT_FDCWD, "/proc/thread-self/fd/4", O_RDWR) = 7 [pid 5002] futex(0x7f159416c40c, FUTEX_WAKE_PRIVATE, 1000000) = 1 [pid 5002] futex(0x7f159416c408, FUTEX_WAIT_PRIVATE, 0, NULL [pid 5001] <... futex resumed>) = 0 [pid 5001] futex(0x7f159416c408, FUTEX_WAKE_PRIVATE, 1000000) = 1 [pid 5002] <... futex resumed>) = 0 [pid 5002] splice(7, NULL, 6, NULL, 256, 0 [pid 5001] futex(0x7f159416c40c, FUTEX_WAIT_PRIVATE, 0, {tv_sec=0, tv_nsec=50000000}) = -1 ETIMEDOUT (Connection timed out) [pid 5001] futex(0x7f159416c41c, FUTEX_WAKE_PRIVATE, 1000000) = 0 [pid 5001] mmap(NULL, 135168, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f1594055000 [pid 5001] mprotect(0x7f1594056000, 131072, PROT_READ|PROT_WRITE) = 0 [pid 5001] clone(child_stack=0x7f15940753f0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID./strace-static-x86_64: Process 5003 attached , parent_tid=[5003], tls=0x7f1594075700, child_tidptr=0x7f15940759d0) = 5003 [pid 5001] futex(0x7f159416c418, FUTEX_WAKE_PRIVATE, 1000000) = 0 [pid 5001] futex(0x7f159416c41c, FUTEX_WAIT_PRIVATE, 0, {tv_sec=0, tv_nsec=50000000} [pid 5003] set_robust_list(0x7f15940759e0, 24) = 0 [pid 5003] write(4, "\x5d\x00\x00\x00\x7d\x01\x00\x00\x00\x43\x00\x00\xfe\x00\x00\x00\x00\x08\x04\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x93\x37\x89\x23\x09\x00\x00\x00\x08\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x03\x00\x2a\x7b\xca\x05\x00\x66\x64\x2f\x34\x00\x05\x00\x66\x64\x2f\x34\x00\x03\x00\x2f\x27\x2e\x05\x00\x66\x64\x2f\x34\x00\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00", 93) = 93 [pid 5003] futex(0x7f159416c41c, FUTEX_WAKE_PRIVATE, 1000000) = 1 [pid 5003] futex(0x7f159416c418, FUTEX_WAIT_PRIVATE, 0, NULL [pid 5001] <... futex resumed>) = 0 syzkaller login: [ 61.972462][ T5002] [ 61.974821][ T5002] ============================================ [ 61.980954][ T5002] WARNING: possible recursive locking detected [ 61.987089][ T5002] 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 Not tainted [ 61.994087][ T5002] -------------------------------------------- [ 62.000244][ T5002] syz-executor318/5002 is trying to acquire lock: [ 62.006641][ T5002] ffff88802838d068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_write+0x140/0x1ca0 [ 62.015432][ T5002] [ 62.015432][ T5002] but task is already holding lock: [ 62.022774][ T5002] ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x39f/0x420 [ 62.032163][ T5002] [ 62.032163][ T5002] other info that might help us debug this: [ 62.040209][ T5002] Possible unsafe locking scenario: [ 62.040209][ T5002] [ 62.047640][ T5002] CPU0 [ 62.050900][ T5002] ---- [ 62.054159][ T5002] lock(&pipe->mutex/1); [ 62.058479][ T5002] lock(&pipe->mutex/1); [ 62.062799][ T5002] [ 62.062799][ T5002] *** DEADLOCK *** [ 62.062799][ T5002] [pid 5001] exit_group(0 [pid 5003] <... futex resumed>) = ? [pid 5003] +++ exited with 0 +++ [pid 5001] <... exit_group resumed>) = ? [ 62.070920][ T5002] May be due to missing lock nesting notation [ 62.070920][ T5002] [ 62.079215][ T5002] 1 lock held by syz-executor318/5002: [ 62.084652][ T5002] #0: ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x39f/0x420 [ 62.094473][ T5002] [ 62.094473][ T5002] stack backtrace: [ 62.100345][ T5002] CPU: 1 PID: 5002 Comm: syz-executor318 Not tainted 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 [ 62.110745][ T5002] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 [ 62.120796][ T5002] Call Trace: [ 62.124069][ T5002] [ 62.126987][ T5002] dump_stack_lvl+0xd9/0x150 [ 62.131588][ T5002] __lock_acquire+0x13eb/0x5f30 [ 62.136445][ T5002] ? print_usage_bug.part.0+0x660/0x660 [ 62.142004][ T5002] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 62.147981][ T5002] ? __lock_acquire+0x1987/0x5f30 [ 62.153004][ T5002] lock_acquire+0x1b1/0x520 [ 62.157496][ T5002] ? pipe_write+0x140/0x1ca0 [ 62.162072][ T5002] ? lock_sync+0x190/0x190 [ 62.166657][ T5002] ? __lock_acquire+0xc17/0x5f30 [ 62.171593][ T5002] __mutex_lock+0x12f/0x1350 [ 62.176182][ T5002] ? pipe_write+0x140/0x1ca0 [ 62.180766][ T5002] ? pipe_write+0x140/0x1ca0 [ 62.185343][ T5002] ? mutex_lock_io_nested+0x11a0/0x11a0 [ 62.190890][ T5002] ? find_held_lock+0x2d/0x110 [ 62.195661][ T5002] ? aa_file_perm+0x567/0x1250 [ 62.200425][ T5002] ? lock_downgrade+0x690/0x690 [ 62.205273][ T5002] pipe_write+0x140/0x1ca0 [ 62.209676][ T5002] ? aa_file_perm+0x591/0x1250 [ 62.214440][ T5002] ? do_proc_dopipe_max_size_conv+0x1c0/0x1c0 [ 62.220504][ T5002] ? aa_path_link+0x2f0/0x2f0 [ 62.225175][ T5002] ? mutex_lock_io_nested+0x11a0/0x11a0 [ 62.230718][ T5002] ? pipe_wait_readable+0x33a/0x420 [ 62.235903][ T5002] ? lock_downgrade+0x690/0x690 [ 62.240744][ T5002] ? _raw_spin_lock_irqsave+0x52/0x60 [ 62.246107][ T5002] do_iter_readv_writev+0x20b/0x3b0 [ 62.251301][ T5002] ? generic_copy_file_range+0x1d0/0x1d0 [ 62.256924][ T5002] ? bpf_lsm_file_permission+0x9/0x10 [ 62.262287][ T5002] ? security_file_permission+0xaf/0xd0 [ 62.267824][ T5002] do_iter_write+0x185/0x7e0 [ 62.272409][ T5002] vfs_iter_write+0x74/0xa0 [ 62.276904][ T5002] iter_file_splice_write+0x743/0xc80 [ 62.282274][ T5002] ? page_cache_pipe_buf_confirm+0x5b0/0x5b0 [ 62.288249][ T5002] ? bpf_lsm_file_permission+0x9/0x10 [ 62.293612][ T5002] ? security_file_permission+0xaf/0xd0 [ 62.299143][ T5002] ? page_cache_pipe_buf_confirm+0x5b0/0x5b0 [ 62.305122][ T5002] do_splice+0xb8c/0x1e50 [ 62.309447][ T5002] ? find_held_lock+0x2d/0x110 [ 62.314201][ T5002] ? splice_file_to_pipe+0x120/0x120 [ 62.319479][ T5002] ? pipe_to_sendpage+0x380/0x380 [ 62.324499][ T5002] __do_splice+0x14e/0x270 [ 62.328910][ T5002] ? do_splice+0x1e50/0x1e50 [ 62.333500][ T5002] __x64_sys_splice+0x19c/0x250 [ 62.338335][ T5002] do_syscall_64+0x39/0xb0 [ 62.342745][ T5002] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 62.350456][ T5002] RIP: 0033:0x7f15940e4079 [ 62.354854][ T5002] 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 [ 62.374446][ T5002] RSP: 002b:00007f1594096278 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 [ 62.382841][ T5002] RAX: ffffffffffffffda RBX: 00007f159416c408 RCX: 00007f15940e4079 [ 62.390796][ T5002] RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000007 [ 62.398749][ T5002] RBP: 00007f159416c400 R08: 0000000000000100 R09: 0000000000000000 [ 62.406702][ T5002] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f159413a040 [ 62.414656][ T5002] R13: 00007f1594096290 R14: 00007f1594096400 R15: 0000000000022000 [pid 5002] <... splice resumed>) = ? [pid 5002] +++ exited with 0 +++ +++ exited with 0 +++ [ 62.422627][ T5002]