====================================================== WARNING: possible circular locking dependency detected 6.3.0-rc5-syzkaller-00137-gf2afccfefe7b #0 Not tainted ------------------------------------------------------ syz-executor.2/29831 is trying to acquire lock: ffff88801b5ae680 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:87 [inline] ffff88801b5ae680 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_fill+0x9f5/0xfc0 net/unix/diag.c:157 but task is already holding lock: ffff88801b5a89e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff88801b5a89e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:69 [inline] ffff88801b5a89e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x909/0xfc0 net/unix/diag.c:157 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rlock-AF_UNIX){+.+.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 skb_queue_tail+0x25/0x150 net/core/skbuff.c:3683 unix_dgram_sendmsg+0xd15/0x1950 net/unix/af_unix.c:2082 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 sock_write_iter+0x295/0x3d0 net/socket.c:1138 call_write_iter include/linux/fs.h:1851 [inline] io_write+0x38b/0x1430 io_uring/rw.c:921 io_issue_sqe+0x15d/0xd20 io_uring/io_uring.c:1907 io_queue_sqe io_uring/io_uring.c:2079 [inline] io_submit_sqe io_uring/io_uring.c:2340 [inline] io_submit_sqes+0x948/0x1d00 io_uring/io_uring.c:2450 __do_sys_io_uring_enter+0x975/0x26e0 io_uring/io_uring.c:3458 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 -> #0 (&u->lock/1){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire kernel/locking/lockdep.c:5669 [inline] lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634 _raw_spin_lock_nested+0x34/0x40 kernel/locking/spinlock.c:378 sk_diag_dump_icons net/unix/diag.c:87 [inline] sk_diag_fill+0x9f5/0xfc0 net/unix/diag.c:157 sk_diag_dump net/unix/diag.c:196 [inline] unix_diag_dump+0x456/0x730 net/unix/diag.c:220 netlink_dump+0x570/0xc50 net/netlink/af_netlink.c:2299 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2404 netlink_dump_start include/linux/netlink.h:308 [inline] unix_diag_handler_dump net/unix/diag.c:319 [inline] unix_diag_handler_dump+0x654/0x9a0 net/unix/diag.c:308 __sock_diag_cmd net/core/sock_diag.c:238 [inline] sock_diag_rcv_msg+0x31e/0x440 net/core/sock_diag.c:269 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2577 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 sock_no_sendpage+0x10c/0x160 net/core/sock.c:3235 kernel_sendpage.part.0+0x1d5/0x700 net/socket.c:3580 kernel_sendpage net/socket.c:3577 [inline] sock_sendpage+0xe7/0x180 net/socket.c:1080 pipe_to_sendpage+0x2b1/0x380 fs/splice.c:454 splice_from_pipe_feed fs/splice.c:508 [inline] __splice_from_pipe+0x449/0x8a0 fs/splice.c:652 splice_from_pipe fs/splice.c:687 [inline] generic_splice_sendpage+0xd8/0x140 fs/splice.c:835 do_splice_from fs/splice.c:856 [inline] do_splice+0xb5b/0x1960 fs/splice.c:1165 __do_splice+0x134/0x250 fs/splice.c:1230 __do_sys_splice fs/splice.c:1437 [inline] __se_sys_splice fs/splice.c:1419 [inline] __ia32_sys_splice+0x199/0x250 fs/splice.c:1419 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rlock-AF_UNIX); lock(&u->lock/1); lock(rlock-AF_UNIX); lock(&u->lock/1); *** DEADLOCK *** 6 locks held by syz-executor.2/29831: #0: ffff88804517f468 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] #0: ffff88804517f468 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock+0x5e/0x70 fs/pipe.c:90 #1: ffffffff8e101f08 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x1b/0x40 net/core/sock_diag.c:279 #2: ffffffff8e102088 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:233 [inline] #2: ffffffff8e102088 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x19f/0x440 net/core/sock_diag.c:269 #3: ffff88801d947688 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: netlink_dump+0xbe/0xc50 net/netlink/af_netlink.c:2246 #4: ffff88805e16c018 (&net->unx.table.locks[i]){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #4: ffff88805e16c018 (&net->unx.table.locks[i]){+.+.}-{2:2}, at: unix_diag_dump+0x1c3/0x730 net/unix/diag.c:214 #5: ffff88801b5a89e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #5: ffff88801b5a89e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:69 [inline] #5: ffff88801b5a89e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x909/0xfc0 net/unix/diag.c:157 stack backtrace: CPU: 3 PID: 29831 Comm: syz-executor.2 Not tainted 6.3.0-rc5-syzkaller-00137-gf2afccfefe7b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire kernel/locking/lockdep.c:5669 [inline] lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634 _raw_spin_lock_nested+0x34/0x40 kernel/locking/spinlock.c:378 sk_diag_dump_icons net/unix/diag.c:87 [inline] sk_diag_fill+0x9f5/0xfc0 net/unix/diag.c:157 sk_diag_dump net/unix/diag.c:196 [inline] unix_diag_dump+0x456/0x730 net/unix/diag.c:220 netlink_dump+0x570/0xc50 net/netlink/af_netlink.c:2299 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2404 netlink_dump_start include/linux/netlink.h:308 [inline] unix_diag_handler_dump net/unix/diag.c:319 [inline] unix_diag_handler_dump+0x654/0x9a0 net/unix/diag.c:308 __sock_diag_cmd net/core/sock_diag.c:238 [inline] sock_diag_rcv_msg+0x31e/0x440 net/core/sock_diag.c:269 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2577 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 sock_no_sendpage+0x10c/0x160 net/core/sock.c:3235 kernel_sendpage.part.0+0x1d5/0x700 net/socket.c:3580 kernel_sendpage net/socket.c:3577 [inline] sock_sendpage+0xe7/0x180 net/socket.c:1080 pipe_to_sendpage+0x2b1/0x380 fs/splice.c:454 splice_from_pipe_feed fs/splice.c:508 [inline] __splice_from_pipe+0x449/0x8a0 fs/splice.c:652 splice_from_pipe fs/splice.c:687 [inline] generic_splice_sendpage+0xd8/0x140 fs/splice.c:835 do_splice_from fs/splice.c:856 [inline] do_splice+0xb5b/0x1960 fs/splice.c:1165 __do_splice+0x134/0x250 fs/splice.c:1230 __do_sys_splice fs/splice.c:1437 [inline] __se_sys_splice fs/splice.c:1419 [inline] __ia32_sys_splice+0x199/0x250 fs/splice.c:1419 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f6e579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7f485cc EFLAGS: 00000296 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000f13 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 retq 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi