====================================================== WARNING: possible circular locking dependency detected 5.15.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/18449 is trying to acquire lock: ffff88807add0678 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:86 [inline] ffff88807add0678 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_fill+0xaa7/0x1100 net/unix/diag.c:154 but task is already holding lock: ffff88807add21e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff88807add21e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:68 [inline] ffff88807add21e0 (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:4843 io_issue_sqe+0x3814/0x7010 fs/io_uring.c:6651 __io_queue_sqe fs/io_uring.c:6978 [inline] io_queue_sqe fs/io_uring.c:7020 [inline] io_submit_sqe fs/io_uring.c:7223 [inline] io_submit_sqes+0x1bca/0x8a20 fs/io_uring.c:7329 __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10043 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 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 kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 _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+0x4b9/0xb70 net/netlink/af_netlink.c:2284 __netlink_dump_start+0x642/0x900 net/netlink/af_netlink.c:2389 netlink_dump_start include/linux/netlink.h:258 [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:2510 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/0xdb0 net/netlink/af_netlink.c:1935 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:2161 [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_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 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.1/18449: #0: ffffffff8d0f8e48 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x17/0x40 net/core/sock_diag.c:275 #1: ffffffff8d0f8fc8 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:229 [inline] #1: ffffffff8d0f8fc8 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x19b/0x440 net/core/sock_diag.c:265 #2: ffff88807cbb4680 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: netlink_dump+0xb0/0xb70 net/netlink/af_netlink.c:2239 #3: ffffffff8d289358 (unix_table_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #3: ffffffff8d289358 (unix_table_lock){+.+.}-{2:2}, at: unix_diag_dump+0x119/0x590 net/unix/diag.c:206 #4: ffff88807add21e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #4: ffff88807add21e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:68 [inline] #4: ffff88807add21e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x9bb/0x1100 net/unix/diag.c:154 stack backtrace: CPU: 0 PID: 18449 Comm: syz-executor.1 Not tainted 5.15.0-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:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 _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+0x4b9/0xb70 net/netlink/af_netlink.c:2284 __netlink_dump_start+0x642/0x900 net/netlink/af_netlink.c:2389 netlink_dump_start include/linux/netlink.h:258 [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:2510 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/0xdb0 net/netlink/af_netlink.c:1935 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:2161 [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_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f11b2711ae9 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:00007f11afc87188 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f11b2824f60 RCX: 00007f11b2711ae9 RDX: 0000000000000001 RSI: 00000000200000c0 RDI: 0000000000000007 RBP: 00007f11b276bf25 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f11b2d58b2f R14: 00007f11afc87300 R15: 0000000000022000