====================================================== WARNING: possible circular locking dependency detected 5.15.0-rc1-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/29777 is trying to acquire lock: ffff88807b12acf0 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:86 [inline] ffff88807b12acf0 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_fill+0x6f2/0x10f0 net/unix/diag.c:154 but task is already holding lock: ffff88807b12a0e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff88807b12a0e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:68 [inline] ffff88807b12a0e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x64b/0x10f0 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}: lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 skb_queue_tail+0x32/0x120 net/core/skbuff.c:3309 unix_dgram_sendmsg+0x199b/0x2a50 net/unix/af_unix.c:1902 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xc1/0xf0 net/socket.c:724 io_send fs/io_uring.c:4773 [inline] io_issue_sqe+0x2924/0x9500 fs/io_uring.c:6624 __io_queue_sqe+0xe3/0x1010 fs/io_uring.c:6907 io_submit_sqe fs/io_uring.c:7134 [inline] io_submit_sqes+0x1680/0x9e00 fs/io_uring.c:7240 __do_sys_io_uring_enter fs/io_uring.c:9882 [inline] __se_sys_io_uring_enter+0x21d/0x1cd0 fs/io_uring.c:9824 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (&u->lock/1){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain+0x1dfb/0x8240 kernel/locking/lockdep.c:3789 __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5015 lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368 sk_diag_dump_icons net/unix/diag.c:86 [inline] sk_diag_fill+0x6f2/0x10f0 net/unix/diag.c:154 sk_diag_dump net/unix/diag.c:192 [inline] unix_diag_dump+0x2e9/0x4f0 net/unix/diag.c:220 netlink_dump+0x5b7/0xc30 net/netlink/af_netlink.c:2278 __netlink_dump_start+0x53d/0x710 net/netlink/af_netlink.c:2383 netlink_dump_start include/linux/netlink.h:258 [inline] unix_diag_handler_dump+0x307/0x7d0 net/unix/diag.c:319 __sock_diag_cmd net/core/sock_diag.c:234 [inline] sock_diag_rcv_msg+0x350/0x460 net/core/sock_diag.c:265 netlink_rcv_skb+0x200/0x470 net/netlink/af_netlink.c:2504 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x814/0x9f0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0xa29/0xe50 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] sock_write_iter+0x39a/0x510 net/socket.c:1057 call_write_iter include/linux/fs.h:2163 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xaf6/0xe70 fs/read_write.c:594 ksys_write+0x18f/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae 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.3/29777: #0: ffffffff8d965048 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x17/0x40 net/core/sock_diag.c:275 #1: ffffffff8d964ea8 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:229 [inline] #1: ffffffff8d964ea8 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x23f/0x460 net/core/sock_diag.c:265 #2: ffff88807dfdc638 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: netlink_dump+0xd0/0xc30 net/netlink/af_netlink.c:2233 #3: ffffffff8da54b98 (unix_table_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #3: ffffffff8da54b98 (unix_table_lock){+.+.}-{2:2}, at: unix_diag_dump+0xf1/0x4f0 net/unix/diag.c:206 #4: ffff88807b12a0e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #4: ffff88807b12a0e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:68 [inline] #4: ffff88807b12a0e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x64b/0x10f0 net/unix/diag.c:154 stack backtrace: CPU: 0 PID: 29777 Comm: syz-executor.3 Not tainted 5.15.0-rc1-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+0x1dc/0x2d8 lib/dump_stack.c:106 check_noncircular+0x2f9/0x3b0 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain+0x1dfb/0x8240 kernel/locking/lockdep.c:3789 __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5015 lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368 sk_diag_dump_icons net/unix/diag.c:86 [inline] sk_diag_fill+0x6f2/0x10f0 net/unix/diag.c:154 sk_diag_dump net/unix/diag.c:192 [inline] unix_diag_dump+0x2e9/0x4f0 net/unix/diag.c:220 netlink_dump+0x5b7/0xc30 net/netlink/af_netlink.c:2278 __netlink_dump_start+0x53d/0x710 net/netlink/af_netlink.c:2383 netlink_dump_start include/linux/netlink.h:258 [inline] unix_diag_handler_dump+0x307/0x7d0 net/unix/diag.c:319 __sock_diag_cmd net/core/sock_diag.c:234 [inline] sock_diag_rcv_msg+0x350/0x460 net/core/sock_diag.c:265 netlink_rcv_skb+0x200/0x470 net/netlink/af_netlink.c:2504 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x814/0x9f0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0xa29/0xe50 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] sock_write_iter+0x39a/0x510 net/socket.c:1057 call_write_iter include/linux/fs.h:2163 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xaf6/0xe70 fs/read_write.c:594 ksys_write+0x18f/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f495540a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000000000029 RSI: 000000002058bfe4 RDI: 0000000000000005 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffe4222977f R14: 00007f495540a300 R15: 0000000000022000