====================================================== WARNING: possible circular locking dependency detected 5.16.0-rc3-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/22871 is trying to acquire lock: ffff888078d5e678 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:86 [inline] ffff888078d5e678 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_fill+0xaa7/0x1100 net/unix/diag.c:154 but task is already holding lock: ffff888078d5d1d8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffff888078d5d1d8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:68 [inline] ffff888078d5d1d8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x9bb/0x1100 net/unix/diag.c:154 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+0x39/0x50 kernel/locking/spinlock.c:162 skb_queue_tail+0x21/0x140 net/core/skbuff.c:3319 unix_dgram_sendmsg+0xf60/0x1950 net/unix/af_unix.c:1939 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 io_send+0x349/0x4d0 fs/io_uring.c:4883 io_issue_sqe+0x3814/0x7060 fs/io_uring.c:6694 __io_queue_sqe fs/io_uring.c:7018 [inline] io_queue_sqe fs/io_uring.c:7060 [inline] io_submit_sqe fs/io_uring.c:7263 [inline] io_submit_sqes+0x1bca/0x8a20 fs/io_uring.c:7369 __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10070 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+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c -> #0 (&u->lock/1){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3063 [inline] check_prevs_add kernel/locking/lockdep.c:3186 [inline] validate_chain kernel/locking/lockdep.c:3801 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 _raw_spin_lock_nested+0x30/0x40 kernel/locking/spinlock.c:368 sk_diag_dump_icons net/unix/diag.c:86 [inline] sk_diag_fill+0xaa7/0x1100 net/unix/diag.c:154 sk_diag_dump net/unix/diag.c:192 [inline] unix_diag_dump+0x399/0x590 net/unix/diag.c:220 netlink_dump+0x4b0/0xb60 net/netlink/af_netlink.c:2265 __netlink_dump_start+0x642/0x900 net/netlink/af_netlink.c:2370 netlink_dump_start include/linux/netlink.h:254 [inline] unix_diag_handler_dump+0x411/0x7d0 net/unix/diag.c:319 __sock_diag_cmd net/core/sock_diag.c:234 [inline] sock_diag_rcv_msg+0x31a/0x440 net/core/sock_diag.c:265 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2491 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x86d/0xda0 net/netlink/af_netlink.c:1916 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 sock_write_iter+0x289/0x3c0 net/socket.c:1057 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x472/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_writev+0x1aa/0x630 fs/read_write.c:924 do_writev+0x27f/0x300 fs/read_write.c:967 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+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c 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.2/22871: #0: ffffffff8d317b88 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x17/0x40 net/core/sock_diag.c:275 #1: ffffffff8d317d08 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:229 [inline] #1: ffffffff8d317d08 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x19b/0x440 net/core/sock_diag.c:265 #2: ffff88803079a680 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: netlink_dump+0xb0/0xb60 net/netlink/af_netlink.c:2220 #3: ffffffff8d4a83b8 (unix_table_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #3: ffffffff8d4a83b8 (unix_table_lock){+.+.}-{2:2}, at: unix_diag_dump+0x119/0x590 net/unix/diag.c:206 #4: ffff888078d5d1d8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #4: ffff888078d5d1d8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:68 [inline] #4: ffff888078d5d1d8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x9bb/0x1100 net/unix/diag.c:154 stack backtrace: CPU: 1 PID: 22871 Comm: syz-executor.2 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2143 check_prev_add kernel/locking/lockdep.c:3063 [inline] check_prevs_add kernel/locking/lockdep.c:3186 [inline] validate_chain kernel/locking/lockdep.c:3801 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 _raw_spin_lock_nested+0x30/0x40 kernel/locking/spinlock.c:368 sk_diag_dump_icons net/unix/diag.c:86 [inline] sk_diag_fill+0xaa7/0x1100 net/unix/diag.c:154 sk_diag_dump net/unix/diag.c:192 [inline] unix_diag_dump+0x399/0x590 net/unix/diag.c:220 netlink_dump+0x4b0/0xb60 net/netlink/af_netlink.c:2265 __netlink_dump_start+0x642/0x900 net/netlink/af_netlink.c:2370 netlink_dump_start include/linux/netlink.h:254 [inline] unix_diag_handler_dump+0x411/0x7d0 net/unix/diag.c:319 __sock_diag_cmd net/core/sock_diag.c:234 [inline] sock_diag_rcv_msg+0x31a/0x440 net/core/sock_diag.c:265 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2491 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x86d/0xda0 net/netlink/af_netlink.c:1916 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 sock_write_iter+0x289/0x3c0 net/socket.c:1057 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x472/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_writev+0x1aa/0x630 fs/read_write.c:924 do_writev+0x27f/0x300 fs/read_write.c:967 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+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf6f1d549 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:00000000f45175fc EFLAGS: 00000296 ORIG_RAX: 0000000000000092 RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00000000200000c0 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 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