create_test_...with_mapping(9)

✨ create_test_...with_mapping(9) ✨

okay so bestie, welcome to the Kernel API Manual — this is the little corner of the kernel docs about create_test_user_ns_with_mapping, and honestly? it's giving "tiny helper, huge main character energy" 💅 let's get into it 🫶

---

🌸 NAME 🌸

create_test_user_ns_with_mapping — makes you a mock user namespace with a UID mapping, no cap 🎀

---

🦋 SYNOPSIS 🦋

struct user_namespace * create_test_user_ns_with_mapping (struct kunit
*test , struct user_namespace *parent_ns , kuid_t mapped_kuid );

like, that's the whole vibe. three args, one pointer back. slay ✨

---

💖 ARGUMENTS 💖

• test — the KUnit test context, aka where the test framework keeps its stuff 🧚
• parent_ns — the parent namespace (typically init_user_ns, iykyk) 👑
• mapped_kuid — the kuid that uid 0 in this namespace maps to over in the parent 🌈

---

🔥 DESCRIPTION 🔥

It creates a minimal user namespace structure for testing, where uid 0 in the namespace maps to a specific kuid in the parent namespace. that's the whole job, and it does it flawlessly, periodt 💅 literally minimal, literally on purpose.

---

⭐ RETURN ⭐

Returns a pointer to the allocated namespace — or NULL on failure 😭 so like, check it, bestie, don't just vibe forward blindly 🙈

---

🎀 SEE ALSO 🎀

Kernel file ./security/commoncap_test.c — the source of truth, go look 🦋

• test_vfsuid_root_in_currentns_init_ns(9)
• test_vfsuid_root_in_currentns_invalid(9)
• test_vfsuid_root_in_currentns_nonzero(9)
• test_kuid_root_in_ns_init_ns_uid0(9)
• test_kuid_root_in_ns_init_ns_nonzero(9)
• test_kuid_root_in_ns_with_mapping(9)
• test_kuid_root_in_ns_with_different_mappings(9)

---

💀 reminder: these are the sibling tests, so if you're deep in ./security and commoncap_test.c, you're exactly where you're supposed to be 💜

---

mwah, that's the page 💖 brought to you from ./security, dated October 2026, and yeah the manual name is Kernel API Manual — now go write that test, bestie, you've got this 🌸🎀✨