====================================================== WARNING: possible circular locking dependency detected 6.9.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor/5216 is trying to acquire lock: ffff888079bad2b0 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff888079bad2b0 (&psock->link_lock){+...}-{2:2}, at: sock_map_add_link net/core/sock_map.c:146 [inline] ffff888079bad2b0 (&psock->link_lock){+...}-{2:2}, at: sock_hash_update_common+0x624/0xa30 net/core/sock_map.c:1041 but task is already holding lock: ffff88807afa4c20 (&htab->buckets[i].lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff88807afa4c20 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_update_common+0x20c/0xa30 net/core/sock_map.c:1025 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&htab->buckets[i].lock){+...}-{2:2}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_hash_delete_elem+0x17c/0x400 net/core/sock_map.c:957 bpf_prog_78b015942f8c5b4e+0x63/0x67 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x28c/0x330 mm/slub.c:4544 sk_psock_free_link include/linux/skmsg.h:423 [inline] sock_map_del_link net/core/sock_map.c:170 [inline] sock_map_unref+0x3ac/0x5e0 net/core/sock_map.c:192 sock_map_update_common+0x4f0/0x5b0 net/core/sock_map.c:518 sock_map_update_elem_sys+0x55f/0x910 net/core/sock_map.c:594 map_update_elem+0x5bf/0x750 kernel/bpf/syscall.c:1654 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5675 __do_sys_bpf kernel/bpf/syscall.c:5794 [inline] __se_sys_bpf kernel/bpf/syscall.c:5792 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x88/0x170 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #0 (&psock->link_lock){+...}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x3a23/0x7fa0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x540 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_map_add_link net/core/sock_map.c:146 [inline] sock_hash_update_common+0x624/0xa30 net/core/sock_map.c:1041 sock_map_update_elem_sys+0x5a4/0x910 net/core/sock_map.c:596 map_update_elem+0x5bf/0x750 kernel/bpf/syscall.c:1654 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5675 __do_sys_bpf kernel/bpf/syscall.c:5794 [inline] __se_sys_bpf kernel/bpf/syscall.c:5792 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x88/0x170 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&htab->buckets[i].lock); lock(&psock->link_lock); lock(&htab->buckets[i].lock); lock(&psock->link_lock); *** DEADLOCK *** 3 locks held by syz-executor/5216: #0: ffff888021137258 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1602 [inline] #0: ffff888021137258 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_sk_acquire net/core/sock_map.c:129 [inline] #0: ffff888021137258 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_update_elem_sys+0x1cc/0x910 net/core/sock_map.c:590 #1: ffffffff8dd312e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #1: ffffffff8dd312e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #1: ffffffff8dd312e0 (rcu_read_lock){....}-{1:2}, at: sock_map_sk_acquire net/core/sock_map.c:130 [inline] #1: ffffffff8dd312e0 (rcu_read_lock){....}-{1:2}, at: sock_map_update_elem_sys+0x1d8/0x910 net/core/sock_map.c:590 #2: ffff88807afa4c20 (&htab->buckets[i].lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #2: ffff88807afa4c20 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_update_common+0x20c/0xa30 net/core/sock_map.c:1025 stack backtrace: CPU: 1 PID: 5216 Comm: syz-executor Not tainted 6.9.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x379/0x4b0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x3a23/0x7fa0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x540 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_map_add_link net/core/sock_map.c:146 [inline] sock_hash_update_common+0x624/0xa30 net/core/sock_map.c:1041 sock_map_update_elem_sys+0x5a4/0x910 net/core/sock_map.c:596 map_update_elem+0x5bf/0x750 kernel/bpf/syscall.c:1654 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5675 __do_sys_bpf kernel/bpf/syscall.c:5794 [inline] __se_sys_bpf kernel/bpf/syscall.c:5792 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x88/0x170 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f8e2447cee9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8e251020c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8e245abf80 RCX: 00007f8e2447cee9 RDX: 0000000000000020 RSI: 0000000020000080 RDI: 0000000000000002 RBP: 00007f8e244c949e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f8e245abf80 R15: 00007ffec46edd98