====================================================== WARNING: possible circular locking dependency detected 6.2.0-rc3-syzkaller-00014-g40c18f363a08 #0 Not tainted ------------------------------------------------------ syz-executor.2/24857 is trying to acquire lock: ffff8880610efe80 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:87 [inline] ffff8880610efe80 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_fill+0x9f5/0xfc0 net/unix/diag.c:157 but task is already holding lock: ffff8880610ee9e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff8880610ee9e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:69 [inline] ffff8880610ee9e8 (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:3572 unix_dgram_sendmsg+0xf45/0x1bc0 net/unix/af_unix.c:2081 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 sock_write_iter+0x295/0x3d0 net/socket.c:1108 call_write_iter include/linux/fs.h:2189 [inline] io_write+0x38b/0x1560 io_uring/rw.c:918 io_issue_sqe+0x156/0x1220 io_uring/io_uring.c:1856 io_queue_sqe io_uring/io_uring.c:2028 [inline] io_submit_sqe io_uring/io_uring.c:2286 [inline] io_submit_sqes+0x96c/0x1e60 io_uring/io_uring.c:2397 __do_sys_io_uring_enter+0xc1d/0x2540 io_uring/io_uring.c:3345 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:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 _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:2286 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2391 netlink_dump_start include/linux/netlink.h:294 [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:2564 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 sock_write_iter+0x295/0x3d0 net/socket.c:1108 call_write_iter include/linux/fs.h:2189 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x182/0x700 fs/read_write.c:861 vfs_writev+0x1aa/0x630 fs/read_write.c:934 do_writev+0x279/0x2f0 fs/read_write.c:977 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 *** 5 locks held by syz-executor.2/24857: #0: ffffffff8e0ca208 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x1b/0x40 net/core/sock_diag.c:279 #1: ffffffff8e0ca388 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:233 [inline] #1: ffffffff8e0ca388 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x19f/0x440 net/core/sock_diag.c:269 #2: ffff88801e5de688 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: netlink_dump+0xbe/0xc50 net/netlink/af_netlink.c:2234 #3: ffff8880599d2958 (&net->unx.table.locks[i]){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #3: ffff8880599d2958 (&net->unx.table.locks[i]){+.+.}-{2:2}, at: unix_diag_dump+0x1c3/0x730 net/unix/diag.c:214 #4: ffff8880610ee9e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #4: ffff8880610ee9e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:69 [inline] #4: ffff8880610ee9e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x909/0xfc0 net/unix/diag.c:157 stack backtrace: CPU: 0 PID: 24857 Comm: syz-executor.2 Not tainted 6.2.0-rc3-syzkaller-00014-g40c18f363a08 #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+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 _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:2286 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2391 netlink_dump_start include/linux/netlink.h:294 [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:2564 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 sock_write_iter+0x295/0x3d0 net/socket.c:1108 call_write_iter include/linux/fs.h:2189 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x182/0x700 fs/read_write.c:861 vfs_writev+0x1aa/0x630 fs/read_write.c:934 do_writev+0x279/0x2f0 fs/read_write.c:977 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: 0023:0xf7f5e549 Code: 03 74 c0 01 10 05 03 74 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 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:00000000f7f595cc EFLAGS: 00000296 ORIG_RAX: 0000000000000092 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00000000200000c0 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi