kasan_slab_pre_free(9)

kasan_slab_pre_free(9) 🎀

Welcome to the Kernel API Manual, bestie ✨ today’s main character is kasan_slab_pre_free, and she’s literally the vibe check before the slab allocator frees an object 💅

🌸 NAME 🌸

kasan_slab_pre_free — check whether freeing a slab object is safe. Yes, the name is the whole assignment, and she ate 👑

✨ SYNOPSIS ✨

bool kasan_slab_pre_free (struct kmem_cache *s , void *object );

🦋 ARGUMENTS 🦋

• s — the man page just says -- undescribed --, so bestie, I’m not gonna invent lore 🙈. It’s a struct kmem_cache *, and that’s what we know.
• object — the object to be freed. That’s the one getting the pre-free safety check 🫶.

💖 DESCRIPTION 💖

Okay so this function checks whether freeing the given object is safe. It may check for double-free and invalid-free bugs and report them. So it’s giving “security guard at the club door” energy, not “actually free it” energy 🔥.

It is intended only for use by the slab allocator. No borrowing it for random side quests, bestie — slab-allocator-only territory 🚫.

And the return value? Return true if freeing the object is unsafe; false otherwise. Yep, the boolean is kinda not matching the “safe” wording in a cute way — true means unsafe, so read it twice before you get cocky 😭.

🔥 SEE ALSO 🔥

Kernel file ./include/linux/kasan.h, plus these iconique functions:

• kasan_unpoison_new_object(9)
• kasan_poison_new_object(9)
• kasan_slab_free(9)
• kasan_mempool_poison_pages(9)
• kasan_mempool_unpoison_pages(9)
• kasan_mempool_poison_object(9)
• kasan_mempool_unpoison_object(9)
• kasan_report(9)

Signed off from source ./include/linux, October 2026, Kernel API Manual — stay safe out there, bestie 💜✨