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charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: possible deadlock in vsock_linger ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.17/6384 is trying to acquire lock: ffff888055028b18 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline] ffff888055028b18 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_linger+0x25e/0x4d0 net/vmw_vsock/af_vsock.c:1080 but task is already holding lock: ffffffff906260a8 (vsock_register_mutex){+.+.}-{4:4}, at: vsock_assign_transport+0xf2/0x900 net/vmw_vsock/af_vsock.c:469 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (vsock_register_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760 vsock_assign_transport+0xf2/0x900 net/vmw_vsock/af_vsock.c:469 vsock_connect+0x201/0xee0 net/vmw_vsock/af_vsock.c:1592 __sys_connect_file+0x141/0x1a0 net/socket.c:2102 __sys_connect+0x13b/0x160 net/socket.c:2121 __do_sys_connect net/socket.c:2127 [inline] __se_sys_connect net/socket.c:2124 [inline] __x64_sys_connect+0x72/0xb0 net/socket.c:2124 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (sk_lock-AF_VSOCK){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 lock_sock_nested+0x41/0xf0 net/core/sock.c:3720 lock_sock include/net/sock.h:1679 [inline] vsock_linger+0x25e/0x4d0 net/vmw_vsock/af_vsock.c:1080 virtio_transport_close net/vmw_vsock/virtio_transport_common.c:1271 [inline] virtio_transport_release+0x52a/0x640 net/vmw_vsock/virtio_transport_common.c:1291 vsock_assign_transport+0x320/0x900 net/vmw_vsock/af_vsock.c:502 vsock_connect+0x201/0xee0 net/vmw_vsock/af_vsock.c:1592 __sys_connect_file+0x141/0x1a0 net/socket.c:2102 __sys_connect+0x13b/0x160 net/socket.c:2121 __do_sys_connect net/socket.c:2127 [inline] __se_sys_connect net/socket.c:2124 [inline] __x64_sys_connect+0x72/0xb0 net/socket.c:2124 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(vsock_register_mutex); lock(sk_lock-AF_VSOCK); lock(vsock_register_mutex); lock(sk_lock-AF_VSOCK); *** DEADLOCK *** 1 lock held by syz.0.17/6384: #0: ffffffff906260a8 (vsock_register_mutex){+.+.}-{4:4}, at: vsock_assign_transport+0xf2/0x900 net/vmw_vsock/af_vsock.c:469 stack backtrace: CPU: 1 UID: 0 PID: 6384 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2043 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 lock_sock_nested+0x41/0xf0 net/core/sock.c:3720 lock_sock include/net/sock.h:1679 [inline] vsock_linger+0x25e/0x4d0 net/vmw_vsock/af_vsock.c:1080 virtio_transport_close net/vmw_vsock/virtio_transport_common.c:1271 [inline] virtio_transport_release+0x52a/0x640 net/vmw_vsock/virtio_transport_common.c:1291 vsock_assign_transport+0x320/0x900 net/vmw_vsock/af_vsock.c:502 vsock_connect+0x201/0xee0 net/vmw_vsock/af_vsock.c:1592 __sys_connect_file+0x141/0x1a0 net/socket.c:2102 __sys_connect+0x13b/0x160 net/socket.c:2121 __do_sys_connect net/socket.c:2127 [inline] __se_sys_connect net/socket.c:2124 [inline] __x64_sys_connect+0x72/0xb0 net/socket.c:2124 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f300598efc9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3006912038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007f3005be5fa0 RCX: 00007f300598efc9 RDX: 0000000000000010 RSI: 0000200000000000 RDI: 0000000000000004 RBP: 00007f3005a11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3005be6038 R14: 00007f3005be5fa0 R15: 00007ffdba0a0048 Tested on: commit: 6548d364 Merge tag 'cgroup-for-6.18-rc2-fixes' of git:.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=162a5492580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f3e7b5a3627a90dd dashboard link: https://syzkaller.appspot.com/bug?extid=10e35716f8e4929681fa compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 patch: https://syzkaller.appspot.com/x/patch.diff?x=17a04e7c580000