STRUCT BINDER_NODE(9)

💅 struct binder_node(9) 💅

okay bestie, welcome to the Kernel API Manual glow-up of struct binder_node(9). This is the binder node bookkeeping page, and yes, it's giving kernel-internal main character energy. Let's get into it 🫶

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✨ NAME ✨

struct binder_node — binder node bookkeeping, but make it make sense.

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💻 SYNOPSIS 💻

struct binder_node {
    int debug_id;
    spinlock_t lock;
    struct binder_work work;
    union {
      struct rb_node rb_node;
      struct hlist_node dead_node;
    };
    struct binder_proc *proc;
    struct hlist_head refs;
    int internal_strong_refs;
    int local_weak_refs;
    int local_strong_refs;
    int tmp_refs;
    binder_uintptr_t ptr;
    binder_uintptr_t cookie;
    struct {
      u8 has_strong_ref:1;
      u8 pending_strong_ref:1;
      u8 has_weak_ref:1;
      u8 pending_weak_ref:1;
    };
    struct {
      u8 accept_fds:1;
      u8 txn_security_ctx:1;
      u8 min_priority;
    };
    bool has_async_transaction;
    struct list_head async_todo;
 };

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🫶 Members 🫶

• debug_id — the unique ID for debugging, and it's invariant after initialized. No cap, it just sits there being itself.
• lock — the lock for node fields. Protect the vibes 🔒
• work — worklist element for node work, and it's protected by proc->inner_lock.
• {unnamed_union} — anonymous. Literally just a union doing union things.
• rb_node — element for the proc->nodes tree, protected by proc->inner_lock.
• dead_node — element for the binder_dead_nodes list, protected by binder_dead_nodes_lock.
• proc — the binder_proc that owns this node, and it's invariant after initialized.
• refs — list of references on this node, protected by lock.
• internal_strong_refs — used to take strong references when initiating a transaction. Protected by proc->inner_lock if proc and by lock.
• local_weak_refs — weak user refs from the local process. Protected by proc->inner_lock if proc and by lock.
• local_strong_refs — strong user refs from the local process. Protected by proc->inner_lock if proc and by lock.
• tmp_refs — temporary kernel refs. Locking lore: protected by proc->inner_lock while proc is valid, and by binder_dead_nodes_lock if proc is NULL. During inc/dec and node release it is also protected by lock to provide safety as the node dies and proc becomes NULL. That's a lot of lock energy, bestie.
• ptr — userspace pointer for the node. It's invariant, no lock needed.
• cookie — userspace cookie for the node. Also invariant, no lock needed 🍪
• {unnamed_struct} — anonymous. Another little struct just existing.
• has_strong_ref — userspace notified of strong ref. Protected by proc->inner_lock if proc and by lock.
• pending_strong_ref — userspace has acked notification of strong ref. Protected by proc->inner_lock if proc and by lock.
• has_weak_ref — userspace notified of weak ref. Protected by proc->inner_lock if proc and by lock.
• pending_weak_ref — userspace has acked notification of weak ref. Protected by proc->inner_lock if proc and by lock.
• {unnamed_struct} — anonymous. Yes, another one. We love a mysterious bitfield moment.
• accept_fds — file descriptor operations supported for the node, and it's invariant after initialized.
• txn_security_ctx — require sender's security context, also invariant after initialized.
• min_priority — minimum scheduling priority, invariant after initialized too.
• has_async_transaction — async transaction to the node in progress, protected by lock.
• async_todo — list of async work items, protected by proc->inner_lock.

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🌸 Description 🌸

Bookkeeping structure for binder nodes. That's the whole plot. It's literally the bookkeeping structure for binder nodes, and it's iconic in a deeply kernel-internal way. Periodt 💅

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🔥 SEE ALSO 🔥

Kernel file ./drivers/android/binder_internal.h

• struct binder_device(9)
• struct binder_work(9)
• struct binder_ref_data(9)
• struct binder_ref(9)
• struct binder_proc(9)
• struct binder_thread(9)
• struct binder_txn_fd_fixup(9)
• struct binder_object(9)

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okay that's the page! sourced from ./drivers/android, dated October 2026, and it's literally struct binder_node(9) — mwah 💋✨