bevyengine/bevy · error

Attempted to free an already-freed binding

Error message

Attempted to free an already-freed binding

What it means

Panic in MaterialBindlessSlotMap::remove: the binding at the given slot is None, i.e. the slot was already freed (or never allocated) when a reference was removed. Indicates double-free of a bindless slot in material binding bookkeeping.

Source

Thrown at crates/bevy_render/src/material_bind_groups.rs:2160

                debug_assert!(self.bindings[slot as usize].is_none());
                self.bindings[slot as usize] = Some(MaterialBindlessBinding::new(resource));

                self.len += 1;
                slot
            }
        }
    }

    /// Removes a reference to an object from the slot.
    ///
    /// If the reference count dropped to 0 and the object was freed, this
    /// method returns true. If the object was still referenced after removing
    /// it, returns false.
    fn remove(&mut self, slot: u32) -> bool {
        let maybe_binding = &mut self.bindings[slot as usize];
        let binding = maybe_binding
            .as_mut()
            .expect("Attempted to free an already-freed binding");

        binding.ref_count -= 1;
        if binding.ref_count != 0 {
            return false;
        }

        let binding_resource_id = binding.resource.binding_resource_id(self.resource_type);
        self.resource_to_slot.remove(&binding_resource_id);

        *maybe_binding = None;
        self.free_slots.push(slot);
        self.len -= 1;
        true
    }
}

impl<R> MaterialBindlessBinding<R>
where

View on GitHub (pinned to 396ca72708)

Solutions

1. Report as a Bevy engine bug with a reproducing project
2. Avoid rapid material/resource destruction sequences that trigger the double free

When it happens

Trigger: Thrown at crates/bevy_render/src/material_bind_groups.rs:2160 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@396ca72708 (2026-08-20). Data as JSON: /api/errors/e0a3b1bfd7ede108. Report an issue: GitHub.