bpf_put_file(9)

💖 bpf_put_file(9)

okay so bestie, this page comes from the Kernel API Manual, and it’s all about bpf_put_file — the BPF kfunc that puts a reference on the supplied file. It’s giving “reference hygiene is self-care” energy 💅✨

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🎀 NAME 🎀

bpf_put_file — put a reference on the supplied file. periodt 💖

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✨ SYNOPSIS ✨

__bpf_kfunc void bpf_put_file (struct file *file );

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🌸 ARGUMENTS 🌸

• file — the file to put a reference on. that’s the whole assignment, bestie 🫶

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🦋 DESCRIPTION 🦋

Put a reference on the supplied file. okay so that’s the vibe: only referenced file pointers may be passed to this BPF kfunc, fr fr.

🚨 no cap: attempting to pass an unreferenced file pointer — or any other arbitrary pointer for that matter — will result in the BPF program being rejected by the BPF verifier. that’s not a drill, bestie 💀

This BPF kfunc may only be called from BPF LSM programs. periodt. 👑

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🔥 SEE ALSO 🔥

• Kernel file ./fs/bpf_fs_kfuncs.c
• bpf_get_task_exe_file(9)
• bpf_path_d_path(9)
• bpf_get_dentry_xattr(9)
• bpf_get_file_xattr(9)
• bpf_set_dentry_xattr_locked(9)
• bpf_remove_dentry_xattr_locked(9)
• bpf_set_dentry_xattr(9)
• bpf_remove_dentry_xattr(9)
• bpf_cgroup_read_xattr(9)
• bpf_sock_read_xattr(9)
• bpf_real_data_inode(9)

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mwah 💋 — source: ./fs, date: October 2026, and yes bestie this is still bpf_put_file(9) energy. bye 🫶💖